Why do some people benefit from some types of exercise more than others? Scientists investigating this question have demonstrated how profiles of certain proteins in the blood can predict a person's "trainability." The work not only sheds new light on the way the human body responds to physical activity, but paves the way for personalized exercise regimes that could prove far more effective for individuals.
“While groups as a whole benefit from exercise, the variability in responses between any two individuals undergoing the very same exercise regimen is actually quite striking," says senior corresponding author on the study Robert E. Gerszten. "For example, some may experience improved endurance while others will see improved blood sugar levels. To date, no aspects of an individual’s baseline clinical profile allow us to predict beforehand who is most likely to derive a significant cardiorespiratory fitness benefit from exercise training.”
The research was led by investigators at Beth Israel Deaconess Medical Center and involved 650 sedentary adults, who undertook a 20-week endurance exercise program. The scientists measured the levels of around 5,000 proteins in the blood of the subjects both before and after they completed the program, which revealed some useful insights.
The team identified a set of 147 proteins that could indicate a person's VO2max, a marker of cardiorespiratory fitness, before the exercise program, and then a set of 102 proteins that could indicate the change in VO2max after it had been completed. Some of these proteins were also found to be linked to a higher risk of early death, highlighting a connection between cardiorespiratory fitness and long-term health.
“We identified proteins that emanate from bone, muscle, and blood vessels that are strongly related to cardiorespiratory fitness and had never been previously associated with exercise training responses,” says Gerszten.
Based in these revelations, the scientists developed what they call a protein score, which could be used to predict how much a person's VO2max would change as a result of the exercise. Baseline levels of certain proteins were able to predict who would respond to the exercise with more reliability than established patient factors, according to the scientists, and also predicted which subjects would be unable to significantly improve their VO2max even after a sharp uptake in physical activity.
“We now have a detailed list of new blood compounds that further inform our understanding of the biology of fitness and exercise adaptation, and predict individual responses to a given exercise regimen,” said Gerszten. “While no pill is ever likely to recapitulate the diversity of benefits from exercise, our study has helped create a roadmap to further explore potential interventions and provides an important step in individualizing exercise as a therapy."
From here, the scientists are working to refine the process and improve its reliability by carrying out further research on larger populations.
The research was published in the journal Nature Metabolism.
