Personality feature could predict how often you exercise
September 20, 2019
Science Daily/Association for Psychological Science
Individuals who make concrete plans to meet their goals may engage in more physical activity, including visits to the gym, compared to those who don't plan quite so far ahead, research shows. These research findings, published in Psychological Science, a journal of the Association for Psychological Science, suggest that self-reported levels of a trait called 'planfulness' may translate into real world differences in behavior.
Some people seem to be able to more consistently meet their goals than others, but it remains unclear if personality traits that have been found to promote goal achievement in the lab similarly encourage individuals to achieve long-term goals in their day-to-day lives, says lead researcher Rita M. Ludwig of the University of Oregon.
Conscientiousness, a measure of individuals' orderliness and dependability on the Big Five Inventory of personality, has long been tied with healthy behaviors, notes Ludwig and colleagues Sanjay Srivastava and Elliot T. Berkman, also of the University of Oregon. Narrowing their focus to a single facet of this trait, planfulness, allows researchers to zero in on the psychological processes -- such as mental flexibility, and a person's ability to make short-term sacrifices in pursuit of future success -- that contribute directly to achieving long-term goals.
"There indeed appears to be a certain way of thinking about goals that correlates with long-term progress," Ludwig says. "What's new in this study is that we used an objective measure of goal progress that could be recorded as participants naturally went about their lives: their check-ins at a local gym."
Ludwig and colleagues examined this relationship by analyzing the gym attendance of 282 participants over a 20-week period. The researchers tracked the number of times each participant swiped into the campus recreation center after enrolling in the study at the start of the winter 2018 academic semester. They also retroactively collected data on gym attendance throughout the fall 2017 term.
The participants, many of whom were students, provided a written description of their exercise plans and completed measures of self-control and grit, in addition to the Big Five Inventory of personality and Ludwig and colleagues' 30-item Planfulness Scale.
While all participants experienced a similar decline in gym attendance over the course of each semester, individuals who rated themselves high on planfulness items such as "developing a clear plan when I have a goal is important to me" went to the gym more throughout both semesters compared to those who ranked themselves lower on planfulness. The researchers found that a one point increase on the five-point Planfulness Scale corresponded with an additional 5.9 recreation center visits during the fall semester, and an additional 8.5 visits after enrolling in the study for the winter semester.
Planfulness was only significantly associated with the frequency of participants' gym attendance during the winter semester, possibly due to participants completing their physical activity plan later in the year, the researchers noted.
"This work is broadly informative for those who are curious about how people pursue health goals, including their own patterns of thought around goals," Ludwig says. "Clinicians might find it helpful in understanding how their patients tend to think about goals and whether person-to-person differences in such thinking are related to outcomes."
While there was a small, but significant relationship between participant planfulness and the level of detail in their physical activity plans, descriptiveness was unexpectedly found to have no relationship with gym attendance, Ludwig and colleagues noted.
"It seems logical that people who are successful with their goals would be able to write in detail about their planning process," Ludwig says. "We were surprised, then, to find no relationship between people's goal pursuit behavior and how they wrote about their goals."
Future psycholinguistic research might investigate alternative explanations for these findings, the researchers conclude.
https://www.sciencedaily.com/releases/2019/09/190920081906.htm
Exercise is good for the aging brain
Researchers find a single bout of exercise boosts cognition, memory performance in some older people
August 26, 2019
Science Daily/University of Iowa
Researchers have found that a single bout of exercise benefits some older people's brains. In experiments in which participants aged 60 to 80 exercised once and multiple times, the researchers found some individuals showed improved cognitive functions and working memory.
Exercise seems to endow a wealth of benefits, from the release of happiness-inducing hormones to higher physical fitness. New research shows it may provide a boost to the mind too.
University of Iowa researchers have found that a single bout of exercise improves cognitive functions and working memory in some older people. In experiments that included physical activity, brain scans, and working memory tests, the researchers also found that participants experienced the same cognitive benefits and improved memory from a single exercise session as they did from longer, regular exercise.
"One implication of this study is you could think of the benefits day by day," says Michelle Voss, assistant professor in the Department of Psychological and Brain Sciences and the study's corresponding author. "In terms of behavioral change and cognitive benefits from physical activity, you can say, 'I'm just going to be active today. I'll get a benefit.' So, you don't need to think of it like you're going to train for a marathon to get some sort of optimal peak of performance. You just could work at it day by day to gain those benefits."
Previous research has shown exercise can confer a mental boost. But the benefits vary: One person may improve cognitively and have improved memory, while another person may show little to no gain.
Limited research has been done on how a single bout of physical activity may affect cognition and working memory specifically in older populations, despite evidence that some brain functions slip as people age.
Voss wanted to tease out how a single session of exercise may affect older individuals. Her team enrolled 34 adults between 60 and 80 years of age who were healthy but not regularly active. Each participant rode a stationary bike on two separate occasions -- with light and then more strenuous resistance when pedaling -- for 20 minutes. Before and after each exercise session, each participant underwent a brain scan and completed a memory test.
In the brain scan, the researchers examined bursts of activity in regions known to be involved in the collection and sharing of memories. In the working memory tests, each participant used a computer screen to look at a set of eight young adult faces that rotated every three seconds -- flashcard style -- and had to decide when a face seen two "cards" previously matched the one they were currently viewing.
After a single exercise session, the researchers found in some individuals increased connectivity between the medial temporal (which surrounds the brain's memory center, the hippocampus) and the parietal cortex and prefrontal cortex, two regions involved in cognition and memory. Those same individuals also performed better on the memory tests. Other individuals showed little to no gain.
The boost in cognition and memory from a single exercise session lasted only a short while for those who showed gains, the researchers found.
"The benefits can be there a lot more quickly than people think," Voss says. "The hope is that a lot of people will then keep it up because those benefits to the brain are temporary. Understanding exactly how long the benefits last after a single session, and why some benefit more than others, are exciting directions for future research."
The participants also engaged in regular exercise, pedaling on a stationary bike for 50 minutes three times a week for three months. One group engaged in moderate-intensity pedaling, while another group had a mostly lighter workout in which the bike pedals moved for them.
Most individuals in the moderate and lighter-intensity groups showed mental benefits, judging by the brain scans and working memory tests given at the beginning and at the end of the three-month exercise period. But the brain gains were no greater than the improvements from when they had exercised a single time.
"The result that a single session of aerobic exercise mimics the effects of 12 weeks of training on performance has important implications both practically and theoretically," the authors write.
The researchers note their study had a small participant pool, with a homogenous population that excluded anyone with chronic health conditions or who were taking beta-blockers.
To address those limitations, Voss has expanded her participant pool in a current, five-year study to confirm the initial findings and learn more about how exercise alters older people's brains. The participants are healthy older individuals who are not physically active, similar to the participants' profile in the study's results reported here.
The National Institute on Aging, part of the National Institutes of Health, funded the research.
https://www.sciencedaily.com/releases/2019/08/190826110409.htm
One or the other: Why strength training might come at the expense of endurance muscles
July 25, 2019
Science Daily/University of Basel
The neurotransmitter brain-derived neurotrophic factor (BDNF) acts in the muscle, so that during strength training endurance muscle fiber number is decreased. Researchers at the University of Basel's Biozentrum have more closely investigated this factor, from the group of myokines, and demonstrated that it is produced by the muscle and acts on both muscles and synapses. The results published in PNAS also provide new insights into age-related muscle atrophy.
Fitness clubs are booming: New gyms are springing up like mushrooms. More and more people are striving to build up and strengthen their muscles. But what exactly happens in the muscle during training? In their recent work, Prof. Christoph Handschin's research group at the Biozentrum, University of Basel, has more closely studied strength muscles and the myokine brain-derived neurotrophic factor (BDNF), which plays an important role in the formation of strength muscle fibers.
Handschin's team has demonstrated that this factor is produced by the muscle itself and remodels the neuromuscular synapses, the neuronal junctions between the motor neurons and muscle. BDNF not only causes the strength muscles to develop, but at the same time leads to endurance muscle fiber number decline.
BDNF acts on muscles and synapses
Generally, it is differentiated between two types of muscle, depending on the type of fibers they are made of: There are the slow-twitch fibers for endurance muscles, which are formed mainly during endurance sports. Marathon runners primarily exercise this type of muscle. A great deal less well studied is the second form of muscle consisting of fast-twitch fibers. These strength muscles gain in volume during strength training and provide particularly great muscular power.
Christoph Handschin's team has now studied the hormone-like neurotransmitter from the myokine family in the mouse model. Myokines are released by the muscle during contraction. "It is interesting that BDNF is produced by the muscle itself and not only exerts an influence on the muscle. At the same time, it affects the neuromuscular synapses, which are the junctions between the motor neurons and muscle," explains Handschin.
BDNF converts endurance muscles into strength muscles
This remodeling of the neuromuscular synapses during strength training results in the body developing more strength muscle fibers. "However, strength muscle growth occurs at the expense of the endurance fibers. More precisely, through the release of BDNF, the endurance muscles are transformed into strength muscles," clarifies Handschin. This makes BDNF a factor proven to be produced by the muscle itself and to influence the type of muscle fibers formed.
Relevance to muscle training and age-related muscle atrophy
The new knowledge gained about the myokine BDNF also provides a possible explanation for the decrease in endurance musculature seen as a result of strength training. This correlation is already being taken into account in the training plan for high performance sports. Particularly in sporting disciplines such as rowing, which are geared towards strength and endurance, the muscle remodeling must be considered.
Moreover, in a follow-up study, the research group showed that in muscle lacking BDNF the age-related decline in muscle mass and function is reduced. "We didn't expect this result," says Handschin. "It also makes the findings interesting for treatment approaches for muscle atrophy in the elderly."
https://www.sciencedaily.com/releases/2019/07/190725112607.htm
Upbeat music can sweeten tough exercise
Insufficiently-active people might benefit from choosing the right tunes
June 20, 2019
Science Daily/University of British Columbia Okanagan campus
New research coming out of UBC's Okanagan campus demonstrates that upbeat music can make a rigorous workout seem less tough. Even for people who are insufficiently active.
Matthew Stork is a postdoctoral fellow in the School of Health and Exercise Sciences. He recently published a study examining how the right music can help less-active people get more out of their workout -- and enjoy it more.
High-intensity interval training (HIIT) -- brief, repeated bouts of intense exercise separated by periods of rest -- has been shown to improve physical health over several weeks of training. But, cautions Stork, it can be perceived as gruelling for many people, especially those who are less active.
"While HIIT is time-efficient and can elicit meaningful health benefits among adults who are insufficiently active, one major drawback is that people may find it to be unpleasant. As a result, this has the potential to discourage continued participation," he says.
Previous research led by Stork and UBC Okanagan's Kathleen Martin Ginis has examined the effects of music during HIIT with recreationally-active people. Their latest study tested the effects of music with participants who were insufficiently-active, used a more rigorous music selection process and implemented a HIIT regimen that is more practical for less-active adults.
The study took place at Brunel University London and Stork worked with Professor Costas Karageorghis, a researcher who studies the effects music has on sport and exercise. First, Stork gathered a panel of British adults to rate the motivational qualities of 16 fast-tempo songs. The three songs with the highest motivational ratings were used for the study.
"Music is typically used as a dissociative strategy. This means that it can draw your attention away from the body's physiological responses to exercise such as increased heart rate or sore muscles," says Stork. "But with high-intensity exercise, it seems that music is most effective when it has a fast tempo and is highly motivational."
Next, a separate group of 24 participants completed what has been referred to as the 'one-minute workout' -- three 20-second all-out sprints, totaling 60 seconds of hard work. A short rest separated the sprints, for a total exercise period of 10 minutes including a warm-up and cool-down. Participants completed these HIIT sessions under three different conditions -- with motivational music, no audio or a podcast that was devoid of music.
Participants reported greater enjoyment of HIIT. They also exhibited elevated heart rates and peak power in the session with music compared to the no-audio and podcast sessions.
"The more I look into this, the more I am surprised," he says. "We believed that motivational music would help people enjoy the exercise more, but we were surprised about the elevated heart rate. That was a novel finding."
Stork believes the elevated heart rates may be explained by a phenomenon called 'entrainment.'
"Humans have an innate tendency to alter the frequency of their biological rhythms toward that of musical rhythms. In this case, the fast-tempo music may have increased people's heart rate during the exercise. It's incredible how powerful music can be."
Stork's research indicates that for people who are deemed insufficiently active, music can not only help them work harder physically during HIIT but it can also help them enjoy HIIT more. And because motivational music has the power to enhance people's HIIT workouts, it may ultimately give people an extra boost to try HIIT again in the future.
"Music can be a practical strategy to help insufficiently active people get more out of their HIIT workouts and may even encourage continued participation."
The study was published this week in the Psychology of Sport and Exercise. Stork received financial support from the Social Sciences and Humanities Research Council of Canada and the Michael Smith Foundation for Health Research over the course of this project.
https://www.sciencedaily.com/releases/2019/06/190620100027.htm
Exercise may have different effects in the morning and evening
June 13, 2019
Science Daily/University of Copenhagen The Faculty of Health and Medical Sciences
Researchers from the University of Copenhagen have learned that the effect of exercise may differ depending on the time of day it is performed. In mice they demonstrate that exercise in the morning results in an increased metabolic response in skeletal muscle, while exercise later in the day increases energy expenditure for an extended period of time.
We probably all know how important a healthy circadian rhythm is. Too little sleep can have severe health consequences. But researchers are still making new discoveries confirming that the body's circadian clock affects our health.
Now, researchers from University of Copenhagen -- in collaboration with researchers from University of California, Irvine -- have learned that the effect of exercise may differ depending on the time of day it is performed. Studies in mice reveal that the effect of exercise performed in the beginning of the mouse' dark/active phase, corresponding to our morning, differs from the effect of exercise performed in the beginning of the light/resting phase, corresponding to our evening.
'There appears to be rather significant differences between the effect of exercise performed in the morning and evening, and these differences are probably controlled by the body's circadian clock. Morning exercise initiates gene programs in the muscle cells, making them more effective and better capable of metabolising sugar and fat. Evening exercise, on the other hand, increases whole body energy expenditure for an extended period of time', says one of the researchers behind the study, Associate Professor Jonas Thue Treebak from the Novo Nordisk Foundation Center for Basic Metabolic Research.
Morning Exercise Is Not Necessarily Better than Evening Exercise
The researchers have measured a number of effects in the muscle cells, including the transcriptional response and effects on the metabolites. The results show that responses are far stronger in both areas following exercise in the morning and that this is likely to be controlled by a central mechanism involving the protein HIF1-alfa, which directly regulates the body's circadian clock.
Morning exercise appears to increase the ability of muscle cells to metabolise sugar and fat, and this type of effect interests the researchers in relation to people with severe overweight and type 2 diabetes.
On the other hand, the results also show that exercise in the evening increases energy expenditure in the hours after exercise. Therefore, the researchers cannot necessarily conclude that exercise in the morning is better than exercise in the evening, Jonas Thue Treebak stresses.
'On this basis we cannot say for certain which is best, exercise in the morning or exercise in the evening. At this point, we can only conclude that the effects of the two appear to differ, and we certainly have to do more work to determine the potential mechanisms for the beneficial effects of exercise training performed at these two time-points. We are eager to extend these studies to humans to identify if timed exercise can be used as a treatment strategy for people with metabolic diseases', he explains.
https://www.sciencedaily.com/releases/2019/06/190613095209.htm
Exercise: Psych patients' new natural prescription
May 21, 2019
Science Daily/University of Vermont
When it comes to inpatient treatment of a range of mental health and mood disorders -- from anxiety and depression to schizophrenia, suicidality and acute psychotic episodes -- a new study suggest that physical exercise is so effective at alleviating patient symptoms that it could reduce patients' time admitted to acute facilities and reliance on psychotropic medications.
"The general attitude of medicine is that you treat the primary problem first, and exercise was never considered to be a life or death treatment option. Now that we know it's so effective, it can become as fundamental as pharmacological intervention," explains David Tomasi, a lecturer at the University of Vermont, psychotherapist and inpatient psychiatry group therapist at the University of Vermont Medical Center and lead researcher of the study.
Practitioners at inpatient psychiatric facilities -- often crowded, acute settings in which patients experience severe distress and discomfort -- typically prescribe psychotropic medications first, rather than natural remedies like physical exercise, to alleviate patients' symptoms such as anger, anxiety and depression. In fact, Tomasi estimates that only a handful of inpatient psychiatric hospitals in the U.S. provide psychotherapist-supported gym facilities exclusively for these patients. Instead, practitioners rely on classical psychotherapeutic and pharmacological frameworks to treat psychiatric symptoms, which they monitor to determine when a patient is ready to be discharged from the facility.
Tomasi, in collaboration with UVMMC's Sheri Gates and Emily Reyns, built a gym exclusively for roughly 100 patients in the medical center's inpatient psychiatry unit, and led and introduced 60-minute structured exercise and nutrition education programs into their treatment plans. The psychotherapists surveyed patients on their mood, self-esteem and self-image both before and after the exercise sessions to gauge the effects of exercise on psychiatric symptoms.
Patients reported lower levels of anger, anxiety and depression, higher self-esteem, and overall improved moods. Tomasi, Gates and Reyns found an average of 95 percent of patients reported that their moods improved after doing the structured exercises, while 63 percent of the patients reported being happy or very happy, as opposed to neutral, sad or very sad, after the exercises. An average of 91.8 of patients also reported that they were pleased with the way their bodies felt after doing the structured exercises.
"The fantastic thing about these results is that, if you're in a psychotic state, you're sort of limited with what you can do in terms of talk therapy or psychotherapy. It's hard to receive a message through talk therapy in that state, whereas with exercise, you can use your body and not rely on emotional intelligence alone" explains Tomasi.
"The priority is to provide more natural strategies for the treatment of mood disorders, depression and anxiety," he adds. "In practice, we hope that every psychiatric facility will include integrative therapies -- in our case, exercise in particular -- as the primary resource for their patients' psycho-physical wellbeing."
https://www.sciencedaily.com/releases/2019/05/190521124650.htm
Keeping fit is more than physical: It's a state of mind
April 30, 2019
Science Daily/Elsevier
According to a new study differences in what motivates individuals and how they self-regulate behavior influence how they keep fit. The study appearing in the journal Heliyon, published by Elsevier, associates personal characteristics with whether people are likely to prefer solo or group exercise activities, CrossFit® training, resistance training, or team sports, how frequently they work out, and if they are likely to stick to their routine.
The investigators set out to better understand why individuals adopt and adhere to regular physical activity programs, whether differences exist in personality, participatory motives, and regulation-motivation styles associated with their exercise modes, and to determine the extent to which these factors predict their work-out frequency. Their findings show that individuals selecting CrossFit, sports, or group exercise were more highly motivated by social connectedness (affiliation) than those engaging primarily in aerobic (e.g., long distance running) or resistance training exercise. Although all participants were highly motivated to engage in physical activity for positive health, those who engaged in resistance training and sport were more motivated by a sense of challenge than ill-health avoidance or weight management.
The study also demonstrated that individual differences in exercise motivation and self-control can predict participation frequency. Individuals who were more motivated by intrinsic reasons such as enjoyment, challenge, and stress management, exercised more frequently; CrossFit participants ranked highest in intrinsic motivation. Prior research has shown that people who exercise typically are more extraverted and conscientious, compared to an average population, but this study did not find any significant personality trait variances linked with different forms of exercise.
"Many individuals who initiate exercise programs may actually select activities that conflict with their interests, styles, personalities, and/or reasons for engagement. Our findings support the need for individualized exercise programs, not only from a physical standpoint, but also from a motivational standpoint. Taking these factors into account may impact the amount of physical activity/exercise that individuals actually complete," explained lead investigator Ms. Allyson Box. who began this work as an undergraduate student at Kennesaw State University, Kennesaw, GA, USA.
Data were collected from more than 400 physically active individuals who completed an online survey distributed via social media. Personality factors, motives for participation, and self-control styles were assessed using widely accepted frameworks including the Five Factor Model, revised Exercise Motivation Inventory, Self-determination Continuum, and Behavioral Regulation in Exercise Questionnaire.
Recent evidence suggests physical activity is important to decrease risks associated with metabolic, osteopathic, cardiovascular, and neurovascular diseases, as well as some cancers and mental health disorders. The positive impact of exercise on overall health is widely acknowledged, but most people tend to avoid physical activity and/or not stick with their regimen. Less than 20 percent of the population meets proposed Physical Activity Guidelines for Americans (2018) by engaging in at least 150 minutes of moderate intensity aerobic activity and at least two instances of resistance exercise each week. This lack of physical activity has resulted in an escalation of chronic diseases, such as diabetes or heart disease.
"We encourage individuals to reflect on their personality and reasons for becoming physically active before diving into a physical activity program to ensure they engage in a physical activity that is compatible with their interest, personality, and goals," the authors added.
"Our findings suggest that it may be more than just seeking the latest 'fitness fad' or 'new diet' in order to influence health outcomes; identifying individual characteristics and motivational factors will aid in developing an exercise program that individuals will stick to over a prolonged period of time, not just a few months."
https://www.sciencedaily.com/releases/2019/04/190430103459.htm
Evening exercise will not ruin sleep and might even reduce appetite
February 21, 2019
Science Daily/The Physiological Society
With growing time demands, many middle-aged adults are finding time to engage in exercise increasingly difficult. For many, even the thought of fitting exercise in after a busy day at work can be as tiring as it is unappetizing. The standing belief that high-intensity exercise should be avoided in the early evening due to its effect on sleep only serves to act as another barrier to exercise at this time.
Must cook dinner. Need to pick the kids up from school. Have to catch up on my favourite TV series. Live too far from the gym. Any of these sound familiar? With growing time demands, many middle-aged adults are finding time to engage in exercise increasingly difficult. For many, even the thought of fitting exercise in after a busy day at work can be as tiring as it is unappetising. The standing belief that high-intensity exercise should be avoided in the early evening due to its effect on sleep only serves to act as another barrier to exercise at this time.
However, encouraging new research published in Experimental Physiology has suggested that 30 minutes of high-intensity exercise performed in the early evening does not negatively affect subsequent sleep, and may also reduce feelings of hunger.
Researchers at Charles Sturt University in Australia recruited eleven middle-aged men to complete three experimental trials to investigate sleep and appetite responses to exercise performed in the morning (6 -- 7 am), afternoon (2 -- 4 pm) and evening (7 -- 9 pm). Participants were required to perform high-intensity cycling involving six one-minute, maximal intensity sprints interspersed by four minutes of rest. Blood collections were taken prior to exercise and following exercise to examine appetite-related hormones, and multiple tests were performed during sleep to assess sleep stages.
The results not only showed that evening exercise did not have a detrimental impact on subsequent sleep, but also that afternoon and evening high-intensity exercise were associated with greater reductions of the hunger stimulating hormone, ghrelin. It is important to note that a single bout of exercise was not linked to reduced hunger, but nevertheless, the observations from this study support high-intensity exercise early in the evening as a viable time-of day for exercise.
As this study's sample size was relatively small, the findings extrapolated to other population groups beyond middle-aged men may be limited, given that sleep and appetite regulation are influenced by sex and age.
Penelope Larsen, lead author of the study, commented said:
"In the future, we hope to conduct similar studies recruiting women, to determine whether sleep and appetite responses may be different depending on sex. Also, this study only considered a single bout of exercise; therefore, it would be beneficial to investigate long-term sleep and appetite adaptations to high-intensity exercise training performed either in the morning, afternoon or evening."
Interestingly, power output during the sprint efforts was higher for the afternoon and evening trials compared to the morning trial, indicating that participants were able to perform better during latter parts of the day. Therefore, time-of-day may also need to be considered when planning training schedules."
https://www.sciencedaily.com/releases/2019/02/190221083411.htm
Exercise could slow withering effects of Alzheimer's
Imaging shows less brain deterioration in physically active people at high risk for dementia
September 17, 2019
Science Daily/UT Southwestern Medical Center
Exercising several times a week may delay brain deterioration in people at high risk for Alzheimer's disease, according to a study that scientists say merits further research to establish whether fitness can affect the progression of dementia.
Research from UT Southwestern found that people who had accumulation of amyloid beta in the brain -- a hallmark of Alzheimer's disease -- experienced slower degeneration in a region of the brain crucial for memory if they exercised regularly for one year.
Although exercise did not prevent the eventual spread of toxic amyloid plaques blamed for killing neurons in the brains of dementia patients, the findings suggest an intriguing possibility that aerobic workouts can at least slow down the effects of the disease if intervention occurs in the early stages.
"What are you supposed to do if you have amyloid clumping together in the brain? Right now doctors can't prescribe anything," said Dr. Rong Zhang, who led the clinical trial that included 70 participants ages 55 and older. "If these findings can be replicated in a larger trial, then maybe one day doctors will be telling high-risk patients to start an exercise plan. In fact, there's no harm in doing so now."
Reduced brain atrophy
The study published in the Journal of Alzheimer's Disease compared cognitive function and brain volume between two groups of sedentary older adults with memory issues: One group did aerobic exercise (at least a half-hour workout four to five times weekly), and another group did only flexibility training.
Both groups maintained similar cognitive abilities during the trial in areas such as memory and problem solving. But brain imaging showed that people from the exercise group who had amyloid buildup experienced slightly less volume reduction in their hippocampus -- a memory-related brain region that progressively deteriorates as dementia takes hold.
"It's interesting that the brains of participants with amyloid responded more to the aerobic exercise than the others," said Dr. Zhang, who conducted the trial at the Institute for Exercise and Environmental Medicine. "Although the interventions didn't stop the hippocampus from getting smaller, even slowing down the rate of atrophy through exercise could be an exciting revelation."
However, Dr. Zhang notes that more research is needed to determine how or if the reduced atrophy rate benefits cognition.
Elusive answers
The search for dementia therapies is becoming increasingly pressing: More than 5 million Americans have Alzheimer's disease, and the number is expected to triple by 2050.
Recent research has helped scientists gain a greater understanding of the molecular genesis of the disease, including a UT Southwestern discovery published last year that is guiding efforts to detect the condition before symptoms arise. Yet the billions of dollars spent on trying to prevent or slow dementia have yielded no proven treatments that would make an early diagnosis actionable for patients.
Fitness and brain health
Dr. Zhang is among a group of scientists across the world trying to determine if exercise may be the first such therapy.
His latest research builds upon numerous studies suggesting links between fitness and brain health. For example, a 2018 study showed that people with lower fitness levels experienced faster deterioration of vital nerve fibers in the brain called white matter. Research in mice has similarly shown exercise correlated with slower deterioration of the hippocampus -- findings that prompted Dr. Zhang to investigate whether the same effects could be found in people.
"I'm excited about the results, but only to a certain degree," Dr. Zhang said. "This is a proof-of-concept study, and we can't yet draw definitive conclusions."
Expanded research
Dr. Zhang is leading a five-year national clinical trial that aims to dig deeper into potential correlations between exercise and dementia.
The trial, which includes six medical centers across the country, involves more than 600 older adults (ages 60-85) at high risk of developing Alzheimer's disease. The study will measure whether aerobic exercise and taking specific medications to reduce high blood pressure and cholesterol can help preserve brain volume and cognitive abilities.
"Understanding the molecular basis for Alzheimer's disease is important," Dr. Zhang said. "But the burning question in my field is, 'Can we translate our growing knowledge of molecular biology into an effective treatment?' We need to keep looking for answers.
https://www.sciencedaily.com/releases/2019/09/190917124832.htm
The fast and the curious: Fitter adults have fitter brains
Large database links fitness to better cognitive performance and healthy white matter in brain
September 9, 2019
Science Daily/European College of Neuropsychopharmacology
In a large study, German scientists have shown that physical fitness is associated with better brain structure and brain functioning in young adults. This opens the possibility that increasing fitness levels may lead to improved cognitive ability, such as memory and problem solving, as well as improved structural changes in the brain. This work is presented for the first time at the ECNP Congress in Copenhagen, with simultaneous publication in the peer-reviewed journal Scientific Reports.
Scientists have previously shown that "exercise is good for the brain," but most studies have not controlled for underlying causes which might give distorted results, such as body weight, blood glucose levels, education status, age and other factors, making it difficult to take an overall view of the benefits. In addition, studies have rarely looked at fitness in relations to both brain structure and mental functioning.
The scientists used a publicly available database of 1206 MRI brain scans from the Human Connectome Project, which had been contributed by volunteers who wanted to contribute to scientific research. The volunteers (average age 30 years old) underwent some additional testing. The first test was a "two-minute walking test," where each person was asked to walk as fast as possible for 2 minutes and the distance was then measured. The volunteers then underwent a series of cognitive tests, to measure such things as memory, sharpness, judgement, and reasoning.
As team leader, Dr Jonathan Repple (University Hospital Muenster, Germany) said "The great strength of this work is the size of the database. Normally when you are dealing with MRI work, a sample of 30 is pretty good, but the existence of this large MRI database allowed us to eliminate possibly misleading factors, and strengthened the analysis considerably."
The tests were able to show two main points: better performance on a 2-minute walking test in young healthy adults is associated with better cognitive performance, and with structural integrity of the white matter in the brain: healthy white matter is known to improve the speed and quality of nerve connections in the brain.
Repple continued, "It surprised us to see that even in a young population cognitive performance decreases as fitness levels drops. We knew how this might be important in an elderly population which does not necessarily have good health, but to see this happening in 30 year olds is surprising. This leads us to believe that a basic level of fitness seems to be a preventable risk factor for brain health.
This type of study raises an important question. We see that fitter people have better brain health, so we now need to ask whether actually making people fitter will improve their brain health. Finding this out is our next step. There are some trials which point in that direction, but if we can prove this using such a large database, this would be very significant."
Commenting, Professor Peter Falkai (University Clinic, Munich, Germany) said:
"This is an important cross-sectional study demonstrating a robust correlation between physical health and cognitive functioning in a large cohort of healthy young adults. This correlation was backed by changes in the white matter status of the brain supporting the notion that better macro-connectivity is related to better brain functioning. It stresses the importance of physical activity at all stages of life and as preliminary recent evidence suggests one can start improving physical health even in later life even if one has never trained before (see reference). These findings however need to be replicated in longitudinal studies and translated for the use in mental illness."
https://www.sciencedaily.com/releases/2019/09/190909121245.htm
Adolescents with high levels of physical activity perform better in school over two years
September 10, 2019
Science Daily/University of Jyväskylä - Jyväskylän yliopisto
Adolescents with higher levels of physical activity performed better in school during transition from primary school to lower secondary school than their physically inactive peers, a new study from Finland shows. However, the researchers, from the University of Jyväskylä, found that increased physical activity did not necessarily result in improved academic performance.
Previous cross-sectional studies have reported that physically more active children and adolescents achieve better school grades than their less active peers do, but there are few longitudinal studies on the topic. A newly published study showed that adolescents with higher levels of physical activity over a follow-up period of two academic years had higher academic performance than did those who were continuously inactive. Furthermore, the study showed that increased levels of physical activity do not automatically result in improved academic performance. Instead, the results suggest that those adolescents who increased their physical activity had lower academic performance during the follow-up compared to their more active peers.
What the results mean
Highly active adolescents performed better in school compared to their less active peers. However, our results showed that increasing physical activity over a period of two academic years did not necessarily improve academic performance.
What the results do not mean
Based on our results, it is not possible to say whether physical activity improves academic performance or if adolescents with higher academic performance choose a physically active lifestyle. Therefore, no causal interpretations can be made. However, the results of the present study do not refute the findings of previous studies showing small but positive effects of physical activity on learning and its neural underpinnings.
'The link between physical activity and academic performance do not always reflect a causal relationship. It is possible that high levels of physical activity and good academic performance share the same attributes, such as high motivation towards the task at hand,' says Eero Haapala, postdoctoral researcher from the University of Jyväskylä.
The study investigated the longitudinal associations of physical activity with academic performance in 635 adolescents who were between 11 and 13 years old at baseline. Physical activity was assessed using a questionnaire and school grades were acquired from the school registers. Several confounding factors such as parental education and pubertal status were controlled for in the analyses.
https://www.sciencedaily.com/releases/2019/09/190910105349.htm adolescents high levels physical activity
Music-based biofeedback shows promise in improving deadlift technique
Musical feedback achieves similar effectiveness to instructor feedback in small study
Science Daily/PLOS
A study of 31 recreational weightlifters suggests that a real-time, music-based feedback system helps improve deadlift technique. Valerio Lorenzoni of Ghent University, Belgium, and colleagues present these findings in the open-access journal PLOS ONE on August 28, 2019.
Sensors placed on the body can provide real-time measurements that help an individual monitor their own athletic performance or progress during rehabilitation. Known as biofeedback, this approach may be especially useful when access to a trainer or therapist is unfeasible, such as during in-home workouts.
For the new study, Lorenzoni and colleagues designed a music-based biofeedback system for helping weightlifters improve their technique while performing a weightlifting exercise known as the deadlift. A person using the system dons 22 body sensors that monitor deadlift technique. Then, they perform deadlifts while listening to music composed by the researchers. Bad technique lowers the sound quality of the music, while improved technique restores it.
To test this system, the scientists recruited 31 recreational weightlifters and divided them into two groups. One group performed deadlifts while receiving the music-based feedback, while the other group received feedback directly from instructors. For simplicity, feedback was provided for only two deadlift technique parameters.
The researchers found that both feedback types resulted in improved deadlift technique among the participants. Both resulted in similar levels of improvement, and participants reported similar levels of clarity and enjoyment for both. These findings suggest that music-based biofeedback could be a useful tool for weight training.
The authors note that future research could explore the long-term effectiveness of their new feedback system. They also suggest that the system could be improved by increasing its portability, and it could be applied to additional parameters of weight training technique.
The authors summarize: "The sonic-instructor is a music-based biofeedback system able to help people improve weightlifting technique for performance improvement and injury prevention."
https://www.sciencedaily.com/releases/2019/08/190828143055.htm
A short bout of exercise enhances brain function
Researchers discover a gene in mice that's activated by brief periods of exercise
July 2, 2019
Science Daily/Oregon Health & Science University
Neuroscientists, working with mice, have discovered that a short burst of exercise directly boosts the function of a gene that increases connections between neurons in the hippocampus, the region of the brain associated with learning and memory.
Most people know that regular exercise is good for your health. New research shows it may make you smarter, too.
Neuroscientists at OHSU in Portland, Oregon, working with mice, have discovered that a short burst of exercise directly boosts the function of a gene that increases connections between neurons in the hippocampus, the region of the brain associated with learning and memory.
The research is published online in the journal eLife.
"Exercise is cheap, and you don't necessarily need a fancy gym membership or have to run 10 miles a day," said co-senior author Gary Westbrook, M.D., senior scientist at the OHSU Vollum Institute and Dixon Professor of Neurology in the OHSU School of Medicine.
Previous research in animals and in people shows that regular exercise promotes general brain health. However, it's hard to untangle the overall benefits of exercise to the heart, liver and muscles from the specific effect on the brain. For example, a healthy heart oxygenates the whole body, including the brain.
"Previous studies of exercise almost all focus on sustained exercise," Westbrook said. "As neuroscientists, it's not that we don't care about the benefits on the heart and muscles but we wanted to know the brain-specific benefit of exercise."
So the scientists designed a study in mice that specifically measured the brain's response to single bouts of exercise in otherwise sedentary mice that were placed for short periods on running wheels. The mice ran a few kilometers in two hours.
The study found that short-term bursts of exercise -- the human equivalent of a weekly game of pickup basketball, or 4,000 steps -- promoted an increase in synapses in the hippocampus. Scientists made the key discovery by analyzing genes that were increased in single neurons activated during exercise.
One particular gene stood out: Mtss1L. This gene had been largely ignored in prior studies in the brain.
"That was the most exciting thing," said co-lead author Christina Chatzi, Ph.D.
The Mtss1L gene encodes a protein that causes bending of the cell membrane. Researchers discovered that when this gene is activated by short bursts of exercise, it promotes small growths on neurons known as dendritic spines -- the site at which synapses form.
In effect, the study showed that an acute burst of exercise is enough to prime the brain for learning.
In the next stage of research, scientists plan to pair acute bouts of exercise with learning tasks to better understand the impact on learning and memory.
https://www.sciencedaily.com/releases/2019/07/190702184555.htm
Exercise improves brain function in overweight and obese individuals
July 9, 2019
Science Daily/Society for the Study of Ingestive Behavior
New findings out of the University of Tübingen show that, on top of its benefits for metabolism, mood, and general health, exercise also improves brain function. In recent studies, researchers learned that obese and overweight individuals are prone to insulin resistance in the brain, where it provides information about current nutritional status, as well as the rest of the body. So researchers wanted to know whether exercise can improve insulin sensitivity in the brain and improve cognition in overweight individuals.
In the current study, led by Dr. Stephanie Kullmann, 22 sedentary adults with overweight or obesity (an average BMI of 31) underwent two brain scans before and after an 8-week exercise intervention, including cycling and walking. Brain function was measured before and after using an insulin nasal spray to investigate insulin sensitivity of the brain. Participants were also assessed for cognition, mood, and peripheral metabolism.
Even though the exercise intervention only resulted in a marginal weight loss, brain functions important for metabolism "normalized" only after 8-weeks. Exercise increased regional blood flow in areas of the brain important for motor control and reward processes, both of which depend on the neurotransmitter dopamine. Dopamine is an important neurotransmitter for learning new motor skills and in reward-related learning and this research shows that exercise significantly improves dopamine-related brain function. One area in particular, the striatum, had enhanced sensitivity to insulin after the 8-weeks of exercise such that the brain response of a person with obesity after exercise training resembled the response of a person with normal-weight. Interestingly, the greater the improvement in brain function, the more belly fat a person lost during the course of the exercise intervention. Behaviorally, participants reported an improvement in mood and task switching, which is an indicator for improved executive function.
"The bottom line is that exercise improves brain function," said Kullmann. "And increasing insulin sensitivity in dopamine-related brain regions through exercise may help decrease the risk of a person to develop type 2 diabetes, along with the benefits for mood and cognition."
https://www.sciencedaily.com/releases/2019/07/190709171815.htm
Over-conditioning kills: Non-traumatic fatalities in football is preventable
July 13, 2019
Science Daily/American Orthopaedic Society for Sports Medicine
Most non-traumatic fatalities among high school and college football athletes do not occur while playing the game of football, but rather during conditioning sessions which are often associated with overexertion or punishment drills required by coaches and team staff, according to research presented today at the American Orthopedic Society for Sports Medicine Annual Meeting. The research was presented by Dr. Barry P. Boden of The Orthopaedic Center, Rockville, Md.
Football is associated with the highest number of fatalities of any high school or college sport, but the number of traumatic injuries incurred while playing football have declined significantly since the 1960s.
However, the annual number of non-traumatic fatalities has stayed constant with current rates that are two to three times higher than traumatic fatalities.
Heat and sickle cell trait fatality rates were compared pre- and post-implementation of the NCAA football acclimatization model in 2003 and sickle cell screening policies implemented in 2010, respectively.
Boden and his team reviewed 187 non-traumatic football fatalities that occurred between 1998 and 2018. The researchers obtained information from extensive internet searches, as well as depositions, investigations, autopsies, media and freedom of information reports.
Of the 187 fatalities, more than half (52 percent) were due to cardiac issues; 24 percent were caused by heat; and five percent from asthma.
"The majority of deaths occurred outside of the regular season months of September through December, with the most common month for fatalities being August," Boden reported.
Boden said many of the fatalities had three issues in common: the conditioning sessions were supervised by the football coach or strength and conditioning coach; irrationally intense workouts and/or punishment drills were scheduled; and an inadequate medical response was implemented.
The average annual rate of heat-related fatalities remained unchanged at the collegiate level pre- and post-implementation of the NCAA football acclimatization model in 2003. The average annual number of sickle cell trait deaths in collegiate football declined 58 percent after the 2010 NCAA sickle cell screening policies were implemented. At the high school level, where there are no sickle cell guidelines, the number of sickle cell fatalities increased 400 percent since 2010.
The football acclimatization model implemented by the NCAA in 2003 has failed at reducing exertional heat-related fatalities at the collegiate level. Sickle cell trait screening policies adopted by the NCAA in 2010 have been effective at reducing fatalities in college athletes and similar guidelines should be mandated at the high school level.
"Conditioning-related fatalities are preventable by establishing standards in workout design, holding coaches and strength and conditioning coaches accountable, ensuring compliance with current policies, and allowing athletic health care providers complete authority over medical decisions," Boden reported.
https://www.sciencedaily.com/releases/2019/07/190713103944.htm
Joint hypermobility related to anxiety, also in animals
The relation could be a universal trait among mammals
June 19, 2019
Science Daily/Universitat Autonoma de Barcelona
Researchers report the first evidence in a non-human species, the domestic dog, of a relation between joint hypermobility and excitability: dogs with more joint mobility and flexibility tend to have more anxiety problems.
The relation between collagen laxity and anxiety in humans is widely known, but this relation has never been observed before in other species. A team of researchers led by professors Jaume Fatjó and Antoni Bulbena from the Department of Psychiatry and Legal Medicine at the UAB, the Hospital del Mar Medical Research Institute (IMIM) and the UAB Affinity Foundation Chair in Animals and Health, analysed a set of 13 animal behaviour characteristics and hip joint mobility in a total of 5575 domestic dogs. The results point to an association between hip joint hypermobility and a brain activation linked to emotions in dogs, with similar results as to those observed in people.
In the case of humans, researchers observed that this relation is made evident by manifestations of anxiety, fear, agoraphobia and panic, and that it is linked to hypermobility thanks to the indirect effects of emotional and mental states through a deregulation of the brain's independent reactions which intensify emotional states. Scientists maintain that excitability, this emotional reactivity, is one of the risk factors for anxiety disorders.
"Many years ago our research group discovered a relation between hypermobility and anxiety, in which people with more joint mobility and flexibility also tended to have more problems with anxiety. Now for the first time we are able to demonstrate that this association also exists in a non-human species," explains Professor Fatjó.
In the new study published in Scientific Reports, of the Nature group, researchers presented the first evidence of an association between hip joint hypermobility and behavioural alterations in a non-human species, which may suggest a very ancient evolutionary link which could be a universal trait in all mammals.
https://www.sciencedaily.com/releases/2019/06/190619111250.htm
Your circle of friends is more predictive of your health
June 17, 2019
Science Daily/University of Notre Dame
To get a better reading on your overall health and wellness, you'd be better off looking at the strength and structure of your circle of friends, according to a new study.
Wearable fitness trackers have made it all too easy for us to make assumptions about our health. We may look to our heart rate to determine whether we really felt the stress of that presentation at work this morning, or think ourselves healthier based on the number of steps we've taken by the end of the day.
But to get a better reading on your overall health and wellness, you'd be better off looking at the strength and structure of your circle of friends, according to a new study in the Public Library of Science journal, PLOS ONE.
While previous studies have shown how beliefs, opinions and attitudes spread throughout our social networks, researchers at the University of Notre Dame were interested in what the structure of social networks says about the state of health, happiness and stress.
"We were interested in the topology of the social network -- what does my position within my social network predict about my health and well-being?" said Nitesh V. Chawla, Frank M. Freimann Professor of Computer Science and Engineering at Notre Dame, director of the Interdisciplinary Center for Network Science and Applications and a lead author of the study. "What we found was the social network structure provides a significant improvement in predictability of wellness states of an individual over just using the data derived from wearables, like the number of steps or heart rate."
For the study, participants wore Fitbits to capture health behavior data -- such as steps, sleep, heart rate and activity level -- and completed surveys and self-assessments about their feelings of stress, happiness and positivity. Chawla and his team then analyzed and modeled the data, using machine learning, alongside an individual's social network characteristics including degree, centrality, clustering coefficient and number of triangles. These characteristics are indicative of properties like connectivity, social balance, reciprocity and closeness within the social network. The study showed a strong correlation between social network structures, heart rate, number of steps and level of activity.
Social network structure provided significant improvement in predicting one's health and well-being compared to just looking at health behavior data from the Fitbit alone. For example, when social network structure is combined with the data derived from wearables, the machine learning model achieved a 65 percent improvement in predicting happiness, 54 percent improvement in predicting one's self-assessed health prediction, 55 percent improvement in predicting positive attitude, and 38 percent improvement in predicting success.
"This study asserts that without social network information, we only have an incomplete view of an individual's wellness state, and to be fully predictive or to be able to derive interventions, it is critical to be aware of the social network structural features as well," Chawla said.
The findings could provide insight to employers who look to wearable fitness devices to incentivize employees to improve their health. Handing someone a means to track their steps and monitor their health in the hopes that their health improves simply may not be enough to see meaningful or significant results. Those employers, Chawla said, would benefit from encouraging employees to build a platform to post and share their experiences with each other. Social network structure helps complete the picture of health and well-being.
"I do believe these incentives that we institute at work are meaningful, but I also believe we're not seeing the effect because we may not be capitalizing on them the way we should," Chawla said. "When we hear that health and wellness programs driven by wearables at places of employment aren't working, we should be asking, is it because we're just taking a single dimensional view where we just give the employees the wearables and forget about it without taking the step to understand the role social networks play in health?"
https://www.sciencedaily.com/releases/2019/06/190617110533.htm
Two hours a week is key dose of nature for health and wellbeing
June 13, 2019
Science Daily/University of Exeter
Spending at least two hours a week in nature may be a crucial threshold for promoting health and wellbeing, according to a new large-scale study.
Research led by the University of Exeter, published in Scientific Reports and funded by NIHR, found that people who spend at least 120 minutes in nature a week are significantly more likely to report good health and higher psychological wellbeing than those who don't visit nature at all during an average week. However, no such benefits were found for people who visited natural settings such as town parks, woodlands, country parks and beaches for less than 120 minutes a week.
The study used data from nearly 20,000 people in England and found that it didn't matter whether the 120 minutes was achieved in a single visit or over several shorter visits. It also found the 120 minute threshold applied to both men and women, to older and younger adults, across different occupational and ethnic groups, among those living in both rich and poor areas, and even among people with long term illnesses or disabilities.
Dr Mat White, of the University of Exeter Medical School, who led the study, said: "It's well known that getting outdoors in nature can be good for people's health and wellbeing but until now we've not been able to say how much is enough. The majority of nature visits in this research took place within just two miles of home so even visiting local urban greenspaces seems to be a good thing. Two hours a week is hopefully a realistic target for many people, especially given that it can be spread over an entire week to get the benefit."
There is growing evidence that merely living in a greener neighbourhood can be good for health, for instance by reducing air pollution. The data for the current research came from Natural England's Monitor of Engagement with the Natural Environment Survey, the world's largest study collecting data on people's weekly contact with the natural world.
Co-author of the research, Professor Terry Hartig of Uppsala University in Sweden said: "There are many reasons why spending time in nature may be good for health and wellbeing, including getting perspective on life circumstances, reducing stress, and enjoying quality time with friends and family. The current findings offer valuable support to health practitioners in making recommendations about spending time in nature to promote basic health and wellbeing, similar to guidelines for weekly physical."
https://www.sciencedaily.com/releases/2019/06/190613095227.htm
Mental well-being predicts leisure time physical activity in midlife
Different exercise activities are related to the different dimensions of well-being in midlife
May 3, 2019
Science Daily/University of Jyväskylä - Jyväskylän yliopisto
Men and women with high mental well-being at the age of 42 were more physically active at the age of 50 compared to those who got lower scores in mental well-being at age 42. Different exercise activities are related to the different dimensions of well-being in midlife.
Mental well-being was investigated through three dimensions: emotional, psychological and social well-being. Emotional well-being indicates overall satisfaction with life and a tendency to have positive feelings. Psychological well-being refers to experiences of personal growth and the purpose of life. Social well-being tells about relationships with other people and the community.
It was a surprise that leisure time physical activity did not predict later mental well-being or subjective health, but mental well-being predicted physical activity. It seems that mental well-being is an important resource for maintaining a physically active lifestyle in midlife, says Dr. Tiia Kekäläinen from the Gerontology Research Center and Faculty of Sport and Health Sciences, University of Jyväskylä, Finland.
Different types of physical activities are good for well-being
Investigation of various leisure time physical activities revealed that different activities are associated with the dimensions of well-being in 50-year-old men and women. Walking was related to emotional well-being, rambling in nature to social well-being and endurance training to subjective health.
"Although exercise did not predict later mental well-being or subjective health in this study, exercise is important for current mental well-being and health," Kekäläinen says.
These associations were found among both men and women, but additionally, rambling in nature was linked to both emotional well-being and subjective health, but only among men.
"It is possible that rambling in nature means different things for men and women. For example, it correlated with the frequency of vigorous exercise only among men," Kekäläinen says.
The data gathered at ages 42 and 50 by questionnaires and interviews for the Jyväskylä Longitudinal Study of Personality and Social Development (JYLS) were used (n = 303). Prof. Lea Pulkkinen started JYLS in 1968 at the Department of Psychology, University of Jyväskylä. Later, JYLS has been moved to the Gerontology Research Center and is led by Research Director Katja Kokko.
https://www.sciencedaily.com/releases/2019/05/190503112740.htm
Training beyond exhaustion can prevent learning
March 5, 2019
Science Daily/eLife
Researchers have found that muscle fatigue caused by overexertion when practicing a skill can affect the task in hand and impair learning afterwards.
The findings, published in the open-access journal eLife, suggest that the common practice of training beyond fatigue should be reconsidered as it could do more harm than good.
The saying goes that 'practice makes perfect'. And although intense repetition of motor skills is a routine part of learning in many disciplines -- from playing a musical instrument to becoming a better artist, a faster runner or perfecting intricate surgical techniques -- it is well known that fatigue eventually starts to degrade our ability to practice a task.
"Surprisingly little is known about the effects of muscle fatigue on our ability to keep learning and getting better at a skill," says first author Meret Branscheidt, former Postdoctoral Fellow in the Department of Physical Medicine and Rehabilitation in the Johns Hopkins University School of Medicine, US. "With this study, we set out to disentangle the effects of fatigue on performance of a task from its effects on the ability to learn and get better at it."
The researchers asked 120 people to learn a pinch-force task over two days. They were given a device that transmits force into a signal received by a computer and asked to hold it between the thumb and index fingers of their dominant hand. During each trial, participants were asked to press the device at different force levels to control the motion of a cursor displayed on a computer screen.
On the first day, a subgroup was asked to continue pinching until they experienced muscle fatigue, which was measured by the extent of contraction they could achieve. On the second day both groups of participants performed the task without reaching the point of fatigue. The researchers found that the ability to get better at the pinch task on the second day was impaired in the group that reached fatigue on day one. In fact, it took them two additional days of training without fatigue to catch up to the same level as the normal (or 'control') group.
The most striking results, however, came from the researchers' next experiment. When they tested performance of the untrained, unfatigued hand in the pinch task, they found that those people who had reached the point of exhaustion performed less well using both their fatigued and unfatigued hands. This suggested that fatigue impairs motor skill learning mechanisms in the brain. To confirm this, the team used magnetic stimulation to disrupt the brain processes thought to be involved in remembering a new skill. This partly alleviated the effect of fatigue on skill learning, which suggests that fatigue may affect the formation of memories that help people to retain new skills they have learned.
Finally, they tested whether muscle fatigue only affects tasks that require high levels of motor control. They asked fatigued and non-fatigued participants to press 10 keys on a computer keyboard in the correct sequence and found no difference in performance on day one or two. This suggests that the detrimental effects of muscle fatigue on learning are specific to tasks that require finely tuned motor skills, but not for more mentally demanding tasks.
"We have shown that learning in a fatigued state results in detrimental effects on a person's ability to acquire a new skill," concludes senior author Pablo Celnik, Director of the Department of Physical Medicine and Rehabilitation at the Johns Hopkins University School of Medicine. "Our observations should be considered carefully when designing training protocols such as in sports and musical performance, as well as for rehabilitation programs."
https://www.sciencedaily.com/releases/2019/03/190305112828.htm