Insufficient sleep associated with risky behavior in teens
Mental health issues, substance abuse, accidents more likely for high school students sleeping less than six hours per night
October 1, 2018
Science Daily/Brigham and Women's Hospital
Researchers examined a national data sample of risk-taking behaviors and sleep duration self-reported by high school students over eight years and found an association between sleep duration and personal safety risk-taking actions.
Adolescents require 8-10 hours of sleep at night for optimal health, according to sleep experts, yet more than 70 percent of high school students get less than that. Previous studies have demonstrated that insufficient slsleep eep in youth can result in learning difficulties, impaired judgement, and risk of adverse health behaviors. In a new study, researchers at Brigham and Women's Hospital examined a national data sample of risk-taking behaviors and sleep duration self-reported by high school students over eight years and found an association between sleep duration and personal safety risk-taking actions. Results are published in a JAMA Pediatrics research letter on October 1.
"We found the odds of unsafe behavior by high school students increased significantly with fewer hours of sleep," said lead author Mathew Weaver, PhD, research fellow, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital. "Personal risk-taking behaviors are common precursors to accidents and suicides, which are the leading causes of death among teens and have important implications for the health and safety of high school students nationally."
Compared to students who reported sleeping eight hours at night, high school students who slept less than six hours were twice as likely to self-report using alcohol, tobacco, marijuana or other drugs, and driving after drinking alcohol. They were also nearly twice as likely to report carrying a weapon or being in a fight. Researchers found the strongest associations were related to mood and self- harm. Those who slept less than six hours were more than three times as likely to consider or attempt suicide, and four times as likely to attempt suicide, resulting in treatment. Only 30 percent of the students in the study reported averaging more than eight hours of sleep on school nights.
The Youth Risk Behavior Surveys are administered biannually by the U.S. Centers for Disease Control and Prevention (CDC) at public and private schools across the country. Researchers used data from 67,615 high school students collected between 2007 and 2015. Personal safety risk-taking behaviors were examined individually and as composite categories. All analyses were weighted to account for the complex survey design and controlled for age, sex, race, and year of survey in mathematical models to test the association between sleep duration and each outcome of interest.
"Insufficient sleep in youth raises multiple public health concerns, including mental health, substance abuse, and motor vehicle crashes," said senior author Elizabeth Klerman, MD, PhD, director of the Analytic Modeling Unit, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital. "More research is needed to determine the specific relationships between sleep and personal safety risk-taking behaviors. We should support efforts to promote healthy sleep habits and decrease barriers to sufficient sleep in this vulnerable population."
https://www.sciencedaily.com/releases/2018/10/181001114300.htm
Household cleaning products may contribute to kids' overweight by altering their gut microbiota
September 17, 2018
Science Daily/Canadian Medical Association Journal
Commonly used household cleaners could be making children overweight by altering their gut microbiota, suggests a new study.
The study analyzed the gut flora of 757 infants from the general population at age 3-4 months and weight at ages 1 and 3 years, looking at exposure to disinfectants, detergents and eco-friendly products used in the home.
Researchers from across Canada looked at data from the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort on microbes in infant fecal matter. They used World Health Organization growth charts for body mass index (BMI) scores.
Associations with altered gut flora in babies 3-4 months old were strongest for frequent use of household disinfectants such as multisurface cleaners, which showed lower levels of Haemophilus and Clostridium bacteria but higher levels of Lachnospiraceae. The researchers also observed an increase in Lachnospiraceae bacteria with more frequent cleaning with disinfectants. They did not find the same association with detergents or eco-friendly cleaners. Studies of piglets have found similar changes in the gut microbiome when exposed to aerosol disinfectants.
"We found that infants living in households with disinfectants being used at least weekly were twice as likely to have higher levels of the gut microbes Lachnospiraceae at age 3-4 months; when they were 3 years old, their body mass index was higher than children not exposed to heavy home use of disinfectants as an infant," said Anita Kozyrskyj, a University of Alberta pediatrics professor, and principal investigator on the SyMBIOTA project, an investigation into how alteration of the infant gut microbiome impacts health.
Babies living in households that used eco-friendly cleaners had different microbiota and were less likely to be overweight as toddlers.
"Those infants growing up in households with heavy use of eco cleaners had much lower levels of the gut microbes Enterobacteriaceae. However, we found no evidence that these gut microbiome changes caused the reduced obesity risk," she said.
She suggests that the use of eco-friendly products may be linked to healthier overall maternal lifestyles and eating habits, contributing in turn to the healthier gut microbiomes and weight of their infants.
"Antibacterial cleaning products have the capacity to change the environmental microbiome and alter risk for child overweight," write the authors. "Our study provides novel information regarding the impact of these products on infant gut microbial composition and outcomes of overweight in the same population."
A related commentary provides perspective on the interesting findings.
"There is biologic plausibility to the finding that early-life exposure to disinfectants may increase risk of childhood obesity through the alterations in bacteria within the Lachnospiraceae family," write epidemiologists Dr. Noel Mueller and Moira Differding, Johns Hopkins Bloomberg School of Public Health, in a related commentary.
They call for further studies "to explore the intriguing possibility that use of household disinfectants might contribute to the complex causes of obesity through microbially mediated mechanisms."
Dr. Kozyrskyj agrees and points to the need for studies that classify cleaning products by their actual ingredients. "The inability to do this was a limitation of our study."
The research study was funded by the Canadian Institutes of Health Research (CIHR) with funding from the Allergy, Genes and Environment (AllerGen) Network of Centres of Excellence for the CHILD study.
https://www.sciencedaily.com/releases/2018/09/180917082435.htm
Teens with concussion may benefit from earlier physical therapy
June 27, 2018
Science Daily/Wolters Kluwer Health
For adolescents with symptoms following a concussion, starting physical therapy (PT) earlier -- within less than three weeks after the injury -- provides outcomes similar to those of later PT.
"Multimodal PT interventions administered by licensed physical therapists may be feasible and safe even within the first few weeks after injury to help facilitate prompt recovery and mitigate the onset of secondary effects from delayed treatment," write Catherine Quatman-Yates, DPT, PhD, of The Ohio State University, Columbus, and colleagues. The study is part of a JNPT special issue on "Rehabilitation Management of Concussion," highlighting research-driven changes geared toward promoting return to activity in young patients with concussion.
Similar Outcomes for Teens with Concussion Undergoing Earlier or Later PT
The researchers looked how the timing of PT affected the course of concussion-related symptoms in 120 adolescents: 78 females and 42 males, median age 14 years. Physical therapy was classified as early (beginning 0 to 20 days after concussion) in 27.5 percent of patients, middle (21 to 41 days) in 32.5 percent, and late (42 days or after) in 40 percent.
The PT program consisted of progressive exercise; vestibular/oculomotor training (targeting inner ear/balance and visual symptoms); and cervical spine manual therapy, stretching, and strengthening exercises. This multimodal treatment was delivered by licensed physical therapists with special training in concussion treatment.
Whether started earlier or later, PT led to similar reductions in concussion-related symptoms. The number of sessions and duration of PT care were similar across groups. There was a low rate of adverse events, most of which were unrelated to PT.
Symptoms worsened in a few patients, more commonly in the late PT group. Some of these patients may have had concussion-related impairments not directly addressed by PT, such as anxiety, depression, or sleep problems.
Recent research has led to new insights into medical management of concussion in children and adolescents. Past guidelines recommended complete physical and cognitive (mental) rest after concussion, until symptoms resolved. But recent studies have suggested that resting for more than a day or two has limited benefits, and may even be linked to increased concussive symptoms.
Today, concussion management is shifting toward a shorter period of rest, followed by gradual return to usual activities, guided by the patient's symptoms. Physical therapy has been recommended for adolescents with persistent symptoms of concussion, generally after three weeks.
The new study provides evidence that starting PT earlier is a safe and feasible approach for adolescents after concussion, with improved symptoms regardless of the timing of the intervention. "Introducing PT earlier in the recovery process may be beneficial in minimizing the potential burden of longer recovery trajectories," Dr. Quatman-Yates and coauthors write. They emphasize the need for further research to determine PT's role in the "optimal plan of care" for young patients with concussion.
Other articles in the special issue include a neuroscience perspective on the role of rest versus physical activity in recovery for young people with concussion, along with new research on changes in vestibular/oculomotor function and the role of balance testing after concussion.
Physical therapists can play a critical role in evaluating and choosing targeted interventions most likely to result in the best outcomes for patients with concussion, according to a Guest Editorial by Karen L. McCulloch, PT, PhD, NCS, and Kathleen Gill-Body, PT, DPT, MS, NCS, FAPTA. They write, "We are in an ideal position to continue our process of returning people to activities and roles that they care about...because it is what we do."
https://www.sciencedaily.com/releases/2018/06/180627160258.htm
How chronic early-life stress raises PTSD vulnerability
Persistent stress in adolescence appears to increase vulnerability through elevated ghrelin levels in rat model and in humans
April 11, 2018
Science Daily/Massachusetts General Hospital
A collaboration between investigators at Massachusetts General Hospital and Khyber Medical University in Pakistan may have discovered how chronic stress experienced early in life increases vulnerability to post-traumatic stress disorder (PTSD) later in life. In their report published in Translational Psychiatry the researchers describe finding that chronic stress induces a persistent increase in the hormone ghrelin, both in a rat model and in human adolescents. Rats with stress-induced ghrelin elevations were more vulnerable to an excessive fear response long after the stressful experience, a vulnerability that was eliminated by long-term blockade of ghrelin signaling.
"Ghrelin is called the 'hunger hormone,' and while it does play an important role in appetite, it has many other effects," says Ki Goosens, PhD, of the MassGeneral Institute for Neurodegenerative Disease, who led the study. "Several teams have shown that repeated stress exposure increases circulating ghrelin levels in many organisms, but those studies examined ghrelin shortly after the stressor exposure ended. Ours is the first to show that traumatic stress increases ghrelin in humans -- specifically in adolescent humans -- and the first to look at ghrelin elevation over long time periods after the end of the stressor."
Considerable evidence supports the impact of early-life stress on brain function and on other health outcomes in human adults. Adolescents are known to have increased emotional reactions to their experiences, and stress may enhance that reactivity, increasing vulnerability to several mental health disorders. Since areas of the brain such as the prefrontal cortex that regulate fear-responsive structures including the amygdala continue to develop during adolescence, stress-induced disruption of the developmental process during adolescence could interfere with those regulatory circuits.
To investigate the potential long-term impact of chronic stress on ghrelin levels, the researchers conducted a series of experiments. Chronic stress was induced in a group of adolescent rats by immobilizing them inside their cages daily for two weeks. A control group was handled daily by research team members over the same time period. Not only were ghrelin levels in the stress-exposed rats significantly higher 24 hours after the last stress exposure, as previously reported, they also remained elevated 130 days later, roughly equivalent to 12 years in human lifespan.
To investigate whether long-term stress produced similar persistent ghrelin elevation in humans, the researcher enrolled 88 children from the Khyber Pukhtunkhwa province of Pakistan, an area affected by more than a decade of terrorist activity. The participants averaged around age 14 at the time of study, and some had either experienced a personal injury or lost a family member in a terrorist attack around four years prior to entering the study. The control group consisted of children who had not experienced those specific types of trauma.
Blood tests revealed that circulating ghrelin levels in the trauma-affected children were around twice those of the control group. Based on interviews with the children and their parents, trauma-affected children also had differences in their sleep, emotional regulation and social isolation, compared with the control group. And while all participants had a body mass index (BMI) within the normal range, the BMIs of trauma-exposed children were significantly lower than those of the control group.
To test the long-term impact of stress-induced ghrelin elevation in the rat model, the research team exposed two other groups of animals to 14 days of either chronic stress induction or daily handling. Two weeks later both groups went through a standard behavioral protocol called fear conditioning, which trained them to expect an unpleasant sensation -- a mild but not painful foot shock -- when they heard a specific sound. After they learn that association, animals will typically 'freeze' in expectation of the shock when they hear that sound. Compared to the control animals, the chronic-stress-exposed rats showed a stronger fear memory by freezing longer during the sound when it was not paired with a shock.
To test whether blocking ghrelin signaling could reduce the stress-enhanced fear response, the researchers administered a drug that blocks the ghrelin receptor to groups of rats over three different schedules -- throughout both the two-week chronic stress induction period and the two weeks prior to fear conditioning, during the stress induction period only or during only the two weeks between stress induction and fear conditioning. While blocking the ghrelin receptor for the full four weeks did eliminate the stress-induced enhanced fear response, blocking ghrelin signaling either only during or only after stress induction did not prevent the enhanced response.
"It appears that blocking the ghrelin receptor throughout the entire period of ghrelin elevation -- both during and after stress -- prevents fear enhancement when the animals subsequently encounter a traumatic event," says Goosens. "But only blocking the receptor during stress, when ghrelin is initially elevated, or after stress, when it remains elevated, does not prevent the fear-enhanced, PTSD-like response."
She adds, "Previous work from my lab shows that exposing brain cells to high levels of ghrelin reduces their sensitivity to the hormone, which we call 'ghrelin resistance.' We've also shown that ghrelin inhibits fear in unstressed individuals, and we believe that stress-induced ghrelin resistance interferes with that inhibition. Finding a way to reverse ghrelin resistance could have important therapeutic implications. The ability to identify individuals who are more vulnerable to the detrimental effects of stress, as well as the 'tipping point' when they become vulnerable, could enable early intervention with either therapy or medication."
https://www.sciencedaily.com/releases/2018/04/180411220806.htm
One in 5 teens report having had a concussion in their lifetime
September 26, 2017
Science Daily/University of Michigan
A new study confirms what many hospital emergency rooms nationwide are seeing: teens playing contact sports suffer from concussions.
In fact, one out of five teens reported at least one concussion diagnosis during their lifetime, and 5.5 percent have had more than one concussion, the study indicated.
The study, published in the Journal of the American Medical Association (JAMA), comes at a time as interest in concussions among pro athletes -- especially those in the National Football League -- has increased in the last decade. Little, however, is known about the prevalence of concussions among teens in the United States, said Phil Veliz, a researcher at the Institute for Research on Women and Gender.
Veliz and colleagues analyzed data from more than 13,088 adolescents in the 2016 Monitoring the Future survey, a national study by U-M funded by the National Institute on Drug Abuse that tracks U.S. students in grades 8, 10 and 12. Students were asked: "Have you ever had a head injury that was diagnosed as a concussion?"
Sociodemographic variables included sex, race/ethnicity, grade level, and participation in competitive sport within the past 12 months. The group, which included 50.2 percent female, indicated if they played at least one of 21 different sports. The findings showed that 19.5 percent reported at least one diagnosed concussion in their lifetime, which was consistent with regional studies and with emergency department reports stating contact sports are a leading cause of concussion among teens.
"Greater effort to track concussions using large-scale epidemiological data are needed to identify high-risk subpopulations and monitor prevention efforts," the researchers wrote.
Several factors, the study noted, were associated with higher lifetime prevalence of reporting a diagnosed concussion: Being male, white, in a higher grade, and participating in competitive sports.
https://www.sciencedaily.com/releases/2017/09/170926112019.htm
Many parents in the dark about concussions
Concussion affects children in numerous sports
July 13, 2017
Science Daily/University of Texas at Arlington
Despite the large volume of information about sports related concussions on the Internet, many parents and guardians of young athletes have a limited understanding of concussions, according to a study.
In the study, which was published in May in the Journal of Applied Behavioral Research, Cynthia Trowbridge, an associate professor of kinesiology and athletic trainer, and co-author Sheetal J. Patel of Stanford University, found that a significant number of caregivers have a limited understanding of concussions and their impact on a child's future.
"They did understand that it's a severe injury but they didn't understand how susceptible patients are," said Trowbridge, a noted expert on concussions in middle and high school athletes. "We found out that despite the fact that all parents had read some brochure or seen some TV show about concussions they had a low self efficacy about awareness. They tended not to know that concussions are associated with all sports, including track and field, volleyball and swimming."
Sports related concussions account for 53 percent of all head injuries in young people under the age of 19, according to the U.S. Centers for Disease Control. The CDC estimates that there are between 1.6 and 3.8 million sports related injuries among young people each year.
Concussions have received heightened attention in recent years because of the large number of retired professional football players who have sued the National Football League. These retired players claim that in some instances they were sent back into games despite the fact that their coaches knew there was a reasonable chance they may have suffered concussions on the gridiron.
In each of the 50 states there are laws requiring teams to take out athletes who may have suffered concussions. The decision is often made by members of the concussion care team, a group of objective health care professionals that includes a physician, an advanced practice nurse and an athletic trainer.
"We live in an age in which parents recognize more than ever the importance of athletics in instilling skills like discipline, concentration, team work and leadership in young people," said Anne Bavier, dean of the College of Nursing and Health Innovation. "But we need to be just as mindful about the kinds of dangerous, unseen injuries that come from playing sports. This study is a useful tool for building awareness and arming parents with some really good information."
Trowbridge said they were motivated to do the study to find out what caregivers understand about concussions and how to better educate them so they can be more effective in looking for symptoms or other possible signs of trouble.
"It's important to involve not only the athletes but the caregivers," said Trowbridge. "It is the caregiver that knows the child the best and can often recognize the signs and symptoms."
She added that studies show many young athletes do not always tell the truth about their symptoms because they want to continue playing.
"We are still learning how concussion symptoms resolve but we know that they don't get better by sending someone right back in with symptoms," Trowbridge said. "Sports is so magical and so many things can be learned from sports, but we have to give the caregivers the tools to be able to protect the youth athlete when they can't protect themselves."
Trowbridge said caregivers should be discriminating when picking physicians to examine their children for possible concussions, adding that not all physicians understand concussions. She encourages them to consult with neurologists, primary care physicians who specialize in sports medicine and concussion specialists when seeking medical advice.
https://www.sciencedaily.com/releases/2017/07/170713154828.htm
PTSD in children quickly and effectively treatable within hours
June 29, 2017
Science Daily/Universiteit van Amsterdam (UVA)
Children and adolescents with posttraumatic stress syndrome (PTSD) can be successfully treated with only a few hours of EMDR or cognitive behavioral writing therapy (CBWT), report researchers.
PTSD is a psychiatric disorder which can develop after exposure to a traumatic event such as a terrorist attack, a road traffic accident, sexual or physical abuse. Previous research shows that PTSD can be treated effectively in adults with Eye Movement Desensitization and Reprocessing (EMDR) or trauma-focused cognitive behavioral therapy/imaginary exposure. Until now, however, strong evidence for the efficacy of EMDR in children has been lacking.
For their study, Carlijn de Roos, a clinical psychologist and UvA researcher, and her fellow researchers compared the effect of EMDR with that of Cognitive Behavioral Writing Therapy (WRITEjunior) in children and adolescents in the age group 8 to 18 who had experienced a single traumatic event like a traffic accident, rape, physical assault or traumatic loss. Both forms of treatment confront the traumatic memory without any preparatory sessions. In EMDR the traumatic memory is activated while at the same time the child's working memory is taxed with an external task (following the fingers of the therapist with the eyes). In writing therapy, the child writes a story on a computer, together with the therapist, about the event and the consequences, including all the horrid aspects of the memory. In the last session, the child shares the story of what happened to him or her with important others.
A total of 103 children and adolescents took part in the study. On average, four sessions were sufficient for successful treatment. 'EMDR and writing therapy were equally effective in reducing posttraumatic stress reactions, anxiety and depression, and behavioral problems. What's more, both proved to be brief and therefore cost effective', says De Roos. 'We literally used a stopwatch to time the length of both trauma treatments. This showed that EMDR reaches positive effects fastest (2 hours and 20 minutes on average) compared to the writing therapy (3 hours and 47 minutes on average). The most important thing, of course, was that the results were lasting, as shown during a follow-up measurement one year later.'
About 16% of children who are exposed to trauma develop PTSD. 'Children who do not get the right treatment suffer unnecessarily and are at risk of developing further problems and being re-traumatized', says De Roos. 'The challenge for health professionals is to identify symptoms of PTSD as quickly as possible and immediately refer for trauma treatment.' According to De Roos, screening for PTSD should become standard practice within the field of childcare for all disorders. 'When PTSD is determined, a brief trauma-focused treatment can significantly diminish symptoms. A brief treatment will not only reduce suffering by child and family, but also lead to tremendous healthcare savings.'
It is important to conduct follow-up research into the effects of EMDR and writing therapy in children with PTSD symptoms who have suffered from multiple traumatic experiences and in children younger than eight, De Roos adds.
https://www.sciencedaily.com/releases/2017/06/170629085311.htm
Studies uncover long-term effects of traumatic brain injury
February 10, 2017
Science Daily/Cincinnati Children's Hospital Medical Center
Doctors are beginning to get answers to the question that every parent whose child has had a traumatic brain injury wants to know: What will my child be like 10 years from now?
In a study to be presented February 10 at the annual meeting of the Association of Academic Physiatrists in Las Vegas, researchers from Cincinnati Children's will present research on long-term effects of TBI -- an average of seven years after injury. Patients with mild to moderate brain injuries are two times more likely to have developed attention problems, and those with severe injuries are five times more likely to develop secondary ADHD. These researchers are also finding that the family environment influences the development of these attention problems.
· Parenting and the home environment exert a powerful influence on recovery. Children with severe TBI in optimal environments may show few effects of their injuries while children with milder injuries from disadvantaged or chaotic homes often demonstrate persistent problems.
· Early family response may be particularly important for long-term outcomes suggesting that working to promote effective parenting may be an important early intervention.
· Certain skills that can affect social functioning, such as speed of information processing, inhibition, and reasoning, show greater long-term effects.
· Many children do very well long-term after brain injury and most do not have across the board deficits.
More than 630,000 children and teenagers in the United States are treated in emergency rooms for TBI each year. But predictors of recovery following TBI, particularly the roles of genes and environment, are unclear. These environmental factors include family functioning, parenting practices, home environment, and socioeconomic status. Researchers at Cincinnati Children's are working to identify genes important to recovery after TBI and understand how these genes may interact with environmental factors to influence recovery.
They will be collecting salivary DNA samples from more than 330 children participating in the Approaches and Decisions in Acute Pediatric TBI Trial.
he primary outcome will be global functioning at 3, 6, and 12 months post injury, and secondary outcomes will include a comprehensive assessment of cognitive and behavioral functioning at 12 months post injury.
This project will provide information to inform individualized prognosis and treatment plans.
Using neuroimaging and other technologies, scientists are also learning more about brain structure and connectivity related to persistent symptoms after TBI. In a not-yet-published Cincinnati Children's study, for example, researchers investigated the structural connectivity of brain networks following aerobic training. The recovery of structural connectivity they discovered suggests that aerobic training may lead to improvement in symptoms.
Over the past two decades, investigators at Cincinnati Children's have conducted a series of studies to develop and test interventions to improve cognitive and behavioral outcomes following pediatric brain injury. They developed an innovative web-based program that provides family-centered training in problem-solving, communication, and self-regulation.
· Across a series of randomized trials, online family problem-solving treatment has been shown to reduce behavior problems and executive dysfunction (management of cognitive processes) in older children with TBI, and over the longer-term improved everyday functioning in 12-17 year olds.
· Web-based parenting skills programs targeting younger children have resulted in improved parent-child interactions and reduced behavior problems. In a computerized pilot trial of attention and memory, children had improvements in sustained attention and parent-reported executive function behaviors. These intervention studies suggest several avenues for working to improve short- and long-term recovery following TBI.
https://www.sciencedaily.com/releases/2017/02/170210165956.htm
Children are as fit as endurance athletes
April 24, 2018
Science Daily/Frontiers
Researchers discover how young children seem to run around all day without getting tired: their muscles resist fatigue and recover in the same way as elite endurance athletes. The study, which compared energy output and post-exercise recovery rates of young boys, untrained adults and endurance athletes, can be used to develop athletic potential in children and improve our knowledge of how disease risk, such as diabetes, increases as our bodies change from childhood to adulthood.
Children not only have fatigue-resistant muscles, but recover very quickly from high-intensity exercise -- even faster than well-trained adult endurance athletes. This is the finding of new research published in open-access journal Frontiers in Physiology, which compared the energy output and post-exercise recovery rates of young boys, untrained adults and endurance athletes. The research could help develop athletic potential in children as well as improve our understanding of how our bodies change from childhood to adulthood -- including how these processes contribute to the risk of diseases such as diabetes.
"During many physical tasks, children might tire earlier than adults because they have limited cardiovascular capability, tend to adopt less-efficient movement patterns and need to take more steps to move a given distance. Our research shows children have overcome some of these limitations through the development of fatigue-resistant muscles and the ability to recover very quickly from high-intensity exercise," say Sébastien Ratel, Associate Professor in Exercise Physiology who completed this study at the Université Clermont Auvergne, France, and co-author Anthony Blazevich, Professor in Biomechanics at Edith Cowan University, Australia.
Previous research has shown that children do not tire as quickly as untrained adults during physical tasks. Ratel and Blazevich suggested the energy profiles of children could be comparable to endurance athletes, but there was no evidence to prove this until now.
The researchers asked three different groups -- 8-12 year-old boys and adults of two different fitness levels -- to perform cycling tasks. The boys and untrained adults were not participants in regular vigorous physical activity. In contrast the last group, the endurance athletes, were national-level competitors at triathlons or long-distance running and cycling.
Each group was assessed for the body's two different ways of producing energy. The first, aerobic, uses oxygen from the blood. The second, anaerobic, doesn't use oxygen and produces acidosis and lactate (often known by the incorrect term, lactic acid), which may cause muscle fatigue. The participants' heart-rate, oxygen levels and lactate-removal rates were checked after the cycling tasks to see how quickly they recovered.
In all tests, the children outperformed the untrained adults.
"We found the children used more of their aerobic metabolism and were therefore less tired during the high-intensity physical activities," says Ratel. "They also recovered very quickly -- even faster than the well-trained adult endurance athletes -- as demonstrated by their faster heart-rate recovery and ability to remove blood lactate."
"This may explain why children seem to have the ability to play and play and play, long after adults have become tired."
Ratel and Blazevich explain the significance of their findings. "Many parents ask about the best way to develop their child's athletic potential. Our study shows that muscle endurance is often very good in children, so it might be better to focus on other areas of fitness such as their sports technique, sprint speed or muscle strength. This may help to optimize physical training in children, so that they perform better and enjoy sports more."
Ratel continues, "With the rise in diseases related to physical inactivity, it is helpful to understand the physiological changes with growth that might contribute to the risk of disease. Our research indicates that aerobic fitness, at least at the muscle level, decreases significantly as children move into adulthood -- which is around the time increases in diseases such as diabetes occur.
"It will be interesting in future research to determine whether the muscular changes we have observed are directly related to disease risk. At least, our results might provide motivation for practitioners to maintain muscle fitness as children grow up; it seems that being a child might be healthy for us."
https://www.sciencedaily.com/releases/2018/04/180424083907.htm
Adolescents who consume diet high in saturated fats may develop poor stress skills
Rat study provides insights into impact of diet on brain functioning during critical developmental period
June 13, 2018
Science Daily/Loma Linda University Adventist Health Sciences Center
Adolescents who consume a diet high in saturated fats may develop poor stress coping skills, signs of post-traumatic stress disorder as adults.
"The teen years are a very critical time for brain maturation, including how well (or not) we'll cope with stress as adults," said Dr. Johnny Figueroa, Assistant Professor, Division of Physiology, Department of Basic Sciences and Center for Health Disparities and Molecular Medicine, Loma Linda University School of Medicine. "The findings of our research support that the lifestyle decisions made during adolescence -- even those as simple as your diet -- can make a big difference in our ability to overcome every day challenges."
The study, "Exposure to an obesogenic diet during adolescence leads to abnormal maturation of neural and behavioral substrates underpinning fear and anxiety," investigated the impact of an obesogenic Western-like high-saturated fat diet on the development of brain areas involved in responding to fear and stress. Study findings demonstrate that the consumption of an obesogenic diet during adolescence has a profound effect on phasic and sustained components of fear in the adult rat. Notably, the rats that consumed the high-saturated fat diet exhibited more anxiety, problems with associative and non-associative learning processes and an impaired fear-startle response.
Startle reflexes, which are studied in humans and lab animals, have a prominent role in anxiety and PTSD research. In this study, consumption of an obesogenic diet during adolescence reduced the extinction of fear memories -- a major impairment observed in people suffering from PTSD. In addition to not properly learning fear associations, the rats on the high-saturated fat diet incorrectly assessed the level of threat. This suggests that obesity and associated metabolic alterations may predispose individuals to PTSD-related psychopathology.
Researchers reported that the animals in the high-saturated fat diet group exhibited alterations in the structure of brain regions associated with PTSD, including the amygdala and the prefrontal cortex. Notably, the group found that the left-brain hemisphere seems to be more vulnerable to the effects of high-saturated fat diet consumption and obesity-related metabolic alterations. Understanding the neural networks that predispose obese adolescents to developing anxiety and stress-related disorders may help target metabolic measures to alleviate the burden of mental illness in this growing population.
Figueroa said the study leaves other questions open for further investigation, such as replicability in human subjects and if the alterations seen in the brain structures are permanent or whether the effects can be reversed. Study limitations include lack of clarity on how the high-saturated fat diet impacts the adult brain, and whether the effects of the obesogenic diet on the fear response are related to deficits in fear memory consolidation, retrieval and expression.
https://www.sciencedaily.com/releases/2018/06/180613113738.htm
Obesity increases dementia risk
November 30, 2017
Science Daily/University College London
People who have a high body mass index (BMI) are more likely to develop dementia than those with a normal weight, according to a new study.
The study, published in the Alzheimer's & Dementia journal, analysed data from 1.3 million adults living in the United States and Europe. The researchers also found that people near dementia onset, who then go on to develop dementia, tend to have lower body weight than their dementia-free counterparts.
"The BMI-dementia association observed in longitudinal population studies, such as ours, is actually attributable to two processes," said lead author of the study, Professor Mika Kivimäki (UCL Institute of Epidemiology & Health). "One is an adverse effect of excess body fat on dementia risk. The other is weight loss due to pre-clinical dementia. For this reason, people who develop dementia may have a higher-than-average body mass index some 20 years before dementia onset, but close to overt dementia have a lower BMI than those who remain healthy."
"The new study confirms both the adverse effect of obesity as well as weight loss caused by metabolic changes during the pre-dementia stage."
Past research on how a person's weight influences their risk of dementia has produced conflicting results. Some findings have suggested that being obese poses a higher dementia risk, but other studies have linked lower weight to increased dementia incidence.
In this study, researchers from across Europe pooled individual-level data from 39 longitudinal population studies from the United States, the United Kingdom, France, Sweden, and Finland. A total of 1,349,857 dementia-free adults participated in these studies and their weight and height were assessed. Dementia was ascertained using linkage to electronic health records obtained from hospitalisation, prescribed medication and death registries.
A total of 6,894 participants developed dementia during up to 38 years of follow-up. Two decades before symptomatic dementia, higher BMI predicted dementia occurrence: each 5-unit increase in BMI was associated with a 16-33% higher risk of this condition (5 BMI units is 14.5kg for a person 5'7" (170cm) tall, approximately the difference in weight between the overweight and normal weight categories or between the obese and overweight categories). In contrast, the mean level of BMI during pre-clinical stage close to dementia onset was lower compared to that in participants who remained healthy.
In 2015, the number of people with dementia reached almost 45 million, two times more than in 1990. This study suggests that maintaining a healthy weight could prevent, or at least delay, dementia.
https://www.sciencedaily.com/releases/2017/11/171130133812.htm
New school of thought: In-class physical exercise won't disrupt learning, teaching
September 17, 2018
Science Daily/University of Michigan
As childhood obesity rates rise and physical education offerings dwindle, elementary schools keep searching for ways to incorporate the federally mandated half-hour of physical activity into the school day.
A series of recent University of Michigan studies found that two-minute bursts of in-class exercise breaks increased the amount of daily exercise for elementary children without hurting math performance. More importantly, when incorporated into classrooms across southeast Michigan, teachers found the breaks were doable and didn't disrupt learning.
"What we're showing is that we can give kids an additional 16 minutes of health-enhancing physical activity," said Rebecca Hasson, principal investigator and one of the lead authors.
Hasson, U-M associate professor of kinesiology and nutritional sciences, is the director of the Childhood Disparities Research Laboratory, which collaborated on the five studies with the U-M schools of public health, education, and architecture and urban planning, and Project Healthy Schools, a statewide community-Michigan Medicine collaborative.
While 16 minutes doesn't sound like much, it adds up, Hasson said. Kids are supposed to get an hour of exercise a day -- 30 minutes of that during school. Most don't.
"Many kids don't have PE every day but they might have recess, and if they get 10 more minutes of activity there, it would meet that school requirement," Hasson said. "This doesn't replace PE, it's a supplement. We're trying to create a culture of health throughout the entire school day, not just in the gym."
The Active Class Space lab studies examined the effect of activity breaks on mood, cognition, appetite and overall physical activity of 39 children in Hasson's lab. A study done in real classrooms tested the feasibility of implementing inPACT (Interrupting Prolonged sitting with ACTivity), the exercise program Hasson and her colleagues developed.
In the lab studies, kids ages 7-11 completed four experiments: eight hours of sitting, interrupted with two-minute low-, moderate- or high-intensity activity breaks, and eight hours of sitting interrupted with two minutes of sedentary screen time.
Findings show that when the sitting was interrupted with high-intensity activity breaks, children maintained their usual activity levels away from the laboratory, thereby burning an additional 150 calories a day without overeating. Unlike adults, children in the study didn't compensate for the increased exercise by sitting around after school or by eating more, Hasson said.
While mood was higher immediately following the screen-time breaks compared to the activity breaks, children reported positive mood during both the sedentary and exercise conditions, and they subsequently rated the activity breaks as more fun.
And, after high-intensity activity, overweight and obese children enjoyed improved moods all day, Hasson said. This suggests children reflected upon the exercise and took more satisfaction in it.
All of the activity breaks elicited the same level of math performance, and when Hasson took the exercise breaks to real classrooms, teachers could do them.
"We got a lot of pushback at first. The fear was that teachers would be overloaded," Hasson said. "Teachers get a lot of stuff thrown at them. Our experience was that teachers were all very positive about exercise. They know it's good for the kids. They were open to the idea but they needed more information on how to do it safely."
U-M's College of Architecture and Urban Planning and School of Education, along with Project Healthy Schools staff, helped design classrooms to accommodate exercise and to safely get kids exercising and then back to class work quickly.
"Teachers were worried it would make kids more rowdy, but 99 percent of kids were back on task within 30 seconds of doing activity breaks," Hasson said. "We even had one teacher who did an activity break in the middle of a math exam -- she realized the benefit of getting them up and moving."
Initially, researchers requested that teachers do 10 three-minute breaks, but most teachers averaged between five and six breaks -- about 15-18 minutes of activity. Schools in disadvantaged districts didn't complete as many activity breaks as schools in wealthier districts. Hasson is currently working to eliminate this disparity by adding elements of game playing -- point scoring, competition, reward system -- to increase physical activity enjoyment in the children.
Based on these studies, Hasson said next they'll try five, four-minute activity breaks totaling 20 minutes, and gauge the impact on mood, activity levels, calorie intake and cognition.
https://www.sciencedaily.com/releases/2018/09/180917114306.htm