Physical activity has been shown to improve mood, cognition, heart health, and aging. Athletes tend to live longer than the average population. They also tend to have lower rates of cancer and cardiovascular disease. These results are more notable among endurance (long-distance running) and mixed (soccer) athletes than among power (weight lifting) athletes.
In recent years, scientists have become increasingly proficient at measuring biological age compared to norms for chronological age. They typically do this by analyzing DNA methylation in a blood or urine sample. However, a new study suggests that high intensity exercise, such as that typical of athletes, may disrupt typical patterns of aging. That, in turn, may make current biological age tests less reliable for athletes.
As bodies age, changes take place. In the nucleus of cells, certain sites on DNA tend to have methyl groups attached to them. In efforts to understand aging, researchers have developed models that use DNA methylation to estimate epigenetic age. This could be helpful in research because it could show that a certain behavior or intervention slows or accelerates aging.
There are limitations to these models, though. The methylation of these sites might not be causing the aging. They may actually be the result of other epigenetic changes. If the changes being tracked could be triggered by non-aging events, the model may not be giving the whole picture.
Models based on one group of people need to be validated for other groups. A recent study compared the DNA methylation of elite athletes with a control of the general population. The epigenetic model that they used involved 5 genes. This 5 gene model was a simplified form of Hannum’s 71 gene model.
The 5 gene model was shown to predict biological age within 5 years. It was developed based on analysis of DNA methylation in hundreds of children and adults in the general population. But some people were unusual outliers.
Researchers found that athletes were more likely to have methylation at 2 of the 5 sites. This suggested that athletes had an older epigenetic age, or that they were aging 3-6 years faster than the general population. Researchers also found that power athletes were more likely to have extra methylation than endurance athletes. And the model lost accuracy for power athletes.
Taken out of context of other research, it would appear that high intensity exercise accelerates aging. However, we know from previous research on longevity that elite athletes tend to live longer and have lower rates of cancer and cardiovascular disease than the general population. So this particular model of aging probably is not accurate for elite athletes, especially power athletes.
When physical activity is stimulating methylation at some sites, it may also cause other epigenetic changes that yield a net protection. For example, methylation at the two sites found in elite athletes suggests decreased resistance to tumors and inflammation. But high intensity exercise provides other benefits that tend to improve mood, cognition, heart health, and longevity overall.