Longevity Briefs: The Benefits Of Exercise Depend On The Immune System

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem: ‘Exercise is healthy’ is about the least controversial statement you could make when it comes to human health. Exercise slows many processes associated with ageing, reduces risk of age-related diseases and increases life expectancy. Thousands of exercise studies are published every year, yet our understanding of exactly how exercise benefits us on a molecular level leaves much to be desired.

This lack of understanding is partly due to just how impactful exercise is on our biology. Exercise has so many molecular effects that it’s difficult to figure out which ones are most important. One effect of exercise is a long term reduction in inflammation. Inflammation is one way the immune system fights infection, but chronic inflammation during ageing contributes to age-related diseases.

The discovery: A study carried out in mice reveals how exercise mobilises special types of immune cells called regulatory T cells (Tregs). While most T cells fight infections and enhance the activity of the immune system, Tregs act as guardians against inflammation and autoimmune disease.

When researchers studied muscle cells from mice that had exercised on a treadmill vs those that were sedentary, they found that exercise caused temporary damage to the muscle tissue, resulting in inflammation, but that the immune system mobilised Tregs to counteract this inflammation. Not only that, but in mice that exercised regularly, Tregs also enhanced the muscles’ ability to use energy and improved their performance. Mice lacking Tregs, on the other hand, did not receive these benefits, nor did mice who only underwent a single exercise session.

The study also identifies interferon, a protein that promotes inflammation, as a key culprit that impairs muscle function and fitness. It appears that Tregs mobilised in response to muscle damage can lower the levels of interferon and protect the muscles from its harmful effects.

The implications: This study suggests that the immune system plays a crucial role in mediating the benefits of exercise, and that Tregs are important for maintaining muscle health and performance. This also has implications for ageing, since both muscle function and the immune system generally decline with increasing age, but can be preserved to some extent through a healthy lifestyle.

For individuals, the study reinforces the importance of regular exercise as a natural way to boost the immune system and reduce inflammation, though we have to remember that mice aren’t humans and that the importance of this mechanism of exercise might vary between species. While this study looked at muscle tissue, it is possible or even likely that exercise enhances Treg activity in other tissues and organs, providing benefits for the whole body. The study also raises the potential of targeting interferon and Tregs as a way to mimic some of the benefits of exercise and perhaps slow the ageing process by suppressing inflammation.