You must know that exercise has many benefits for the body. Long-term exercise can enhance immunity and cognition, improve cardiovascular function, and promote metabolism and help lose weight. But in addition to long-term changes, exercise also has many immediate effects on physiological processes such as metabolism and immunity.
Scientists at the Stanford University School of Medicine recently conducted a study that conducted a detailed and comprehensive analysis of what happened in a group of volunteers' bodies shortly after they exercised. The results revealed thousands of changes at the molecular level, involving energy metabolism, inflammation, oxidative stress, tissue repair, and cardiovascular response. The authors of the study pointed out that this is the most comprehensive molecular study on personalized exercise testing to date.
The study recruited 36 volunteers aged 40 to 75 and asked them to do aerobic exercise on a treadmill. The classic cardiopulmonary exercise test measures peak oxygen consumption (VO2), which is the maximum oxygen consumption of a person during strenuous exercise, through an oxygen mask worn by the volunteers. This is an important indicator of aerobic exercise capacity and the gold standard for assessing health in medicine.
However, the research team led by Professor Michael Snyder wanted to know more than just the maximum oxygen consumption. They first drew blood samples from the volunteers before running as a reference standard for comparison with the post-exercise results. Then, after the volunteers ran for 8 to 12 minutes and reached their peak oxygen consumption, the researchers asked them to get off the treadmill and collected blood samples from the volunteers 2 minutes, 15 minutes, 30 minutes, and 60 minutes after reaching the peak.
Next, the researchers conducted multi-omics analysis of plasma and peripheral blood mononuclear cells from these samples, including metabolome, lipidome, immunome, proteome and transcriptome. "We can use all these measurements to describe the molecular events that occur in chronological order after exercise." Professor Snyder explained, "We know that exercise causes a series of physiological responses, such as inflammation, metabolism and hormone fluctuations, but through (longitudinal multi-omics) measurements, we can describe these changes in unprecedented detail."
The researchers measured hundreds of thousands of molecules and observed that the levels of thousands of molecules changed at different times before and after exercise. They divided these molecules into four categories based on their changing trends after exercise.
Some molecules increased dramatically 2 minutes after stopping exercise, that is, shortly after reaching the maximum oxygen consumption. For example, molecules related to inflammatory response, oxidative stress and complex lipid metabolism. The results of fatty acid oxidation also intuitively tell us that after just a few minutes of intense exercise, the body is "burning fat" quickly.
Different energy metabolism molecular markers have different changes. Two minutes after the exercise, the blood sample showed that the body obtained energy by metabolizing certain amino acids. But 15 minutes after the exercise, the body switched to metabolizing glucose for energy. The body uses glycogen as a storage form of glucose. "The body breaks down glycogen as part of the post-exercise repair response, so the peak (of sugar metabolism molecular markers) appears slightly later." The study authors explained.
There are hundreds of molecules whose levels drop due to exercise and slowly recover within an hour after the exercise. At the center of this molecular network are two metabolic hormones, leptin and ghrelin. The researchers pointed out in the paper that "this shows the role of exercise in regulating appetite", which can also explain why hunger is usually suppressed just after high-intensity exercise.
Among these volunteers, some had insulin resistance, meaning their bodies could not process glucose properly. The researchers also compared their molecular responses with those of healthy volunteers, providing new insights into the pathophysiology of insulin resistance. "One of the main differences we saw was that the immune response after exercise was much weaker in individuals with insulin resistance," said Professor Snyder.
Interestingly, the researchers unexpectedly found that participants with high peak oxygen consumption had a group of molecules in their pre-exercise blood samples that showed a high correlation with strong aerobic capacity. "This made us think that we could develop a test method to predict a person's fitness level," said Dr. Kévin Contrepois, co-first author of the study.
The researchers said they have been developing an algorithm to select a subset of thousands of molecules that are highly correlated with peak oxygen consumption results. They hope that in the future they can optimize a simple, fast and economical health test method to objectively measure a person's aerobic capacity and serve personalized precision medicine.
"Aerobic fitness is one of the best measures of longevity, so having this information available through a simple blood test would be extremely valuable in monitoring an individual's health," added Dr. Contrepois.
