Molecular effects of exercise detailed
May 28, 2020
Science Daily/Stanford Medicine
A simple blood test may be able to determine how physically fit you are, according to a new study conducted by scientists at the Stanford University School of Medicine.
The test could complement treadmill tests, a more traditional clinical evaluation of fitness, and provide individuals with far more nuanced information about their body's molecular response to exercise.
The blood test is an offshoot of a complex study conducted by a team of researchers that took hundreds of thousands of molecular measurements from a group of individuals before and after exercising.
"Everybody knows exercise is good for you, but we really don't know what drives that at a molecular level," said Michael Snyder, PhD, professor and chair of genetics. "Our goal at the outset was to conduct a highly comprehensive analysis of what's happening in the body just after exercising."
The team tracked molecular markers of a wide array of biological processes, such as metabolism, immunity, oxidative stress and cardiovascular function. Hundreds of thousands of measurements from 36 study participants provided a window into the sea of chemical fluctuations the body experiences during intense exercise. To the scientists' knowledge, such comprehensive measurements of post-exercise molecular fluctuations have never been performed. What's more, the team saw that the participants who were most physically fit shared similar molecular signatures in their resting blood samples captured before exercise.
"It gave us the idea that we could develop a test to predict someone's level of fitness," said Kévin Contrepois, PhD, director of metabolomics and lipidomics in the Department of Genetics. "Aerobic fitness is one of the best measures of longevity, so a simple blood test that can provide that information would be valuable to personal health monitoring."
With the preliminary data, the team has created a proof-of-principle test, for which they've filed a patent application. The test is not currently available to the public.
A paper describing the study will be published May 28 in Cell. Snyder, who holds the Stanford W. Ascherman, MD, FACS, Professorship in Genetics, and Francois Haddad, MD, clinical professor of medicine, are co-senior authors of the study. Contrepois shares lead authorship with postdoctoral scholars Si Wu, PhD, and Daniel Hornburg, PhD, and with clinical assistant professor Kegan Moneghetti, MD, PhD.
A flurry of change
Snyder's team set out to better understand the molecular shifts that underlie changes in physical fitness. The gold standard of medical fitness assessments is a peak VO2 test, which measures a person's peak oxygen consumption during intense exercise and uses the score as a proxy for aerobic fitness. But Snyder and his team wanted more detail -- specifically, about the ways in which exercise initiates change at the molecular level.
They performed VO2 testing for 36 individuals, including Snyder, on a treadmill. Participants, both male and female, had an average body mass index of 29 kilograms/meter squared, and their age range was from 40 to 75 years old. Before the treadmill test, the researchers drew a baseline blood sample. Participants then donned an oxygen-measuring mask and ran at a slight incline until they reached peak oxygen consumption, at which point they stopped and got off the treadmill. The researchers took blood samples from participants 2 minutes, 15 minutes, 30 minutes and 60 minutes after they had reached their peaks.
"All of these measurements allow us to describe a choreography of molecular events that occur after physical exercise," Snyder said. "We know that exercise causes an array of physiological responses, such as inflammation, metabolism and hormone fluctuation, but these measurements allowed us to characterize those changes in unprecedented detail."
It turns out that in the first two minutes post-exercise, the body experiences an intense flurry of molecular activity. In most participants, molecular markers of inflammation, tissue healing and oxidative stress, a natural byproduct of metabolism, spiked sharply shortly after hopping off the treadmill, as their bodies began to recover. Molecular markers of metabolism varied, Snyder said. At 2 minutes, blood samples revealed evidence that the body was metabolizing certain amino acids for energy, but it switched to metabolizing glucose, a type of sugar, around 15 minutes. "The body breaks down glycogen as part of its exercise recovery response, so that's why we see that spike a little later," Snyder said. Glycogen is a form of stored glucose.
As part of the study, Snyder also compared the molecular response in individuals who were insulin resistant, meaning they're unable to process glucose properly, with the response in individuals who could process glucose normally. "The main difference we see is that insulin resistant individuals have a dampened immune response post-exercise," he said.
Blood test for fitness
Although it wasn't the team's original intent, they noticed some consistencies in the baseline measurements of the participants who performed better on the peak VO2 test. In these individuals, the researchers saw a strong correlation between a set of molecules and an individual's level of aerobic fitness. They discovered a collection of thousands of molecules -- including markers of immunity, metabolism and muscle activity -- that correlate with a person's aerobic fitness. "At this point, we don't fully understand the connection between some of these markers and how they are related to better fitness," Snyder said. The researchers hope to unravel those connections in a future investigation.
Snyder said that because the molecular profiling done in the study was so thorough, it wouldn't be practical for doctors to use in their clinics; it would be expensive and provide more information than necessary. But his team is working on whittling down the biomarkers to those that are most representative of a person's fitness level in an effort to make the test practical for broader use. Already, the team is developing an algorithm to select a subset of these molecules that are highly correlative to peak VO2 results, Contrepois said. As the researchers continue to optimize the fitness test, they hope it can one day be a faster, cheaper and more convenient way for people to objectively measure aerobic fitness.
https://www.sciencedaily.com/releases/2020/05/200528115826.htm
Higher aerobic fitness levels are associated with better word production skills in healthy older adults
April 30, 2018
Science Daily/University of Birmingham
Researchers found that older adults' aerobic fitness levels are directly related to the incidence of age-related language failures such as 'tip-of-the-tongue' states.
Healthy older people who exercise regularly are less inclined to struggle to find words to express themselves, research led by the University of Birmingham has discovered.
Researchers found that older adults' aerobic fitness levels are directly related to the incidence of age-related language failures such as 'tip-of-the-tongue' states.
The research, published today in Scientific Reports, is the first of its kind to investigate the relationship between aerobic fitness levels and temporary cognitive lapses, such as not having a word come to mind when speaking -- known as a 'tip-of-the-tongue' state.
People in a tip-of-the-tongue state have a strong conviction that they know a word, but are unable to produce it, and this phenomena occurs more frequently as we grow older.
The University of Birmingham study -- carried out in collaboration with the University of Agder in Norway, the University of Leuven in Belgium and King's College London -- measured the occurrence of tip-of-the-tongue states in a psycholinguistic experiment.
The study saw a group of 28 healthy adults (20 women with the average age of 70 and 8 men with the average age of 67), being compared in a 'tip-of-the-tongue' language test to 27 young people (19 women with the average age of 23 and 8 men with the average age of 22).
The test involved a 'definition filling task', done on a computer. They were asked to name famous people in the UK, such as authors, politicians and actors, based on 20 questions about them. They were also given the definitions of 20 'low frequency' and 20 'easy' words and asked whether they knew the word relating to the definition.
The participants' underwent a static bike cycling test -- a gold standard test which quantified their ability to use oxygen during exercise and their resulting individual aerobic fitness levels.
Lead author Dr Katrien Segaert, of the University of Birmingham's School of Psychology, said: "Older adults free from medical diseases still experience age-related cognitive decline.
"Significantly, what we found was that the degree of decline is related to one's aerobic fitness.
"In our study, the higher the older adults' aerobic fitness level, the lower the probability of experiencing a tip-of-the-tongue state.
"Importantly, our results also showed that the relationship between the frequency of tip-of-the-tongue occurrences and aerobic fitness levels exists over and above the influence of a person's age and vocabulary size."
Dr Segaert said that tip-of-the-tongue states are uniquely a problem with language functioning.
"Older adults sometimes worry that tip-of-the-tongue states indicate serious memory problems but this is a misconception: tip-of-the-tongue states are not associated with memory loss," she added. "In fact, older adults usually have a much larger vocabulary than young adults. Instead, tip-of-the-tongue states occur when the meaning of a word is available in our memory, but the sound form of the word can temporarily not be accessed."
"Accessing the sound forms of words is essential for successful and fluent language production, and its disruption has very noticeable negative consequences for older adults."
She said she hoped the study would add gravitas to the public health message that regular exercise is important to ensure healthy ageing.
She added: "There are a lot of findings already on the benefits of aerobic fitness and regular exercise, and our research demonstrates another side of the benefits, namely a relationship between fitness and language skills. We were able to show, for the first time, that the benefits of aerobic fitness extend to the domain of language."
"Maintaining good language skills is extremely important for older adults. Older adults frequently have word finding difficulties and they experience these as particularly irritating and embarrassing."
"Speaking is a skill we all rely on every day. Communication with others helps us maintain social relationships and independence into old age."
In future research, the University of Birmingham plans to undertake exercise intervention studies to determine whether regular exercise can successfully increase language abilities.
https://www.sciencedaily.com/releases/2018/04/180430075622.htm
Aerobic Fitness, Hormones Predict Recognition Memory in Young Adults
Dec. 2, 2013 —
Science Daily/Boston University School of Medicine (BUSM)
Researchers at Boston University School of Medicine (BUSM) have found further evidence that exercise may be beneficial for brain health and cognition. The findings, which are currently available online in Behavioural Brain Research, suggest that certain hormones, which are increased during exercise, may help improve memory.
Hormones called growth factors are thought to mediate the relationship between exercise and brain health. The hippocampus, a region of the brain crucial for learning and memory, is thought to be uniquely affected by these hormones.
The growth factors brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), and insulin-like growth factor-1 (IGF-1), have been implicated in the link between exercise and hippocampal function. BDNF, for example, acts on the nervous system to help regulate communication between existing brain cells (neurons) and stimulate the growth and maturation of new hippocampal neurons and blood vessels.
In this study, the researchers recruited healthy young adults, in whom they measured blood hormone levels together with performance on a recognition memory task and aerobic fitness. The researchers were thus able to correlate the blood hormone levels with aerobic fitness, and subsequently whether there was any effect on memory function.
According to the researchers, BDNF and aerobic fitness predicted memory in an interactive manner, suggesting that at low fitness BDNF levels negatively predicted expected memory accuracy. Conversely, at high fitness resting BDNF levels positively predicted recognition memory. There also was a strong association between IGF-1 and aerobic fitness; however there was no complementary link between IGF-1 and memory function.
"We will be continuing this line of research by testing if memory improves following an exercise training program in both young and geriatric adults, and by adding brain imaging techniques," explained Karin Schon, PhD, assistant professor of anatomy and neurobiology at BUSM, who served as the study's principal investigator.
http://www.sciencedaily.com/releases/2013/12/131202162204.htm