Longevity Briefs: Football Players Appear Biologically Younger After A Match

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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:

If we want to measure whether a treatment slows down biological ageing, we need a way to measure it. This is where epigenetic clocks come in. To understand these, we first need to understand DNA methylation. The DNA is an instruction manual containing the information needed to build everything within the body. Molecular ‘tags’ called methyl groups can be added to the DNA in order to control which genes are used, without changing the genetic code itself.

Patterns of DNA methylation change throughout life. By measuring DNA methylation within someone’s genome and comparing it to the population average, scientists can estimate their biological age. If their biological age is found to be greater than their actual (chronological) age, it suggests that they may be ageing more rapidly than average.

While the measurements of the most sophisticated epigenetic clocks correlate well with health and lifespan, biological age is not the only factor that influences epigenetic age. We previously covered a study that found that for some popular epigenetic clocks, measured epigenetic age varied by as much as 3 years depending on whether it was measured at midnight or at noon. Here we have another study that shows that measured epigenetic age is lower in football players after a match. What exactly does this mean?

The discovery:

The study involved 24 members of a professional German football team, 19 of whom were involved in the epigenetic age prediction analysis and had an average (mean) age of 24. The researchers wanted to investigate the effects of physical stress on the players. The 5 supporting staff members (mean age of 42) were used as a control group, since they experienced a similar environmental factors except for physical stress. Epigenetic age was measured from saliva samples collected before and after games, taken at up to 10 different time points over a 6-month period during the 2021/22 and 2022/23 professional football seasons. Blood samples were also collected at 6 time points so that cell counts could be measured.

Epigenetic age was measured using three clocks: DNAmGrimAge2, DNAmFitAge and the Skin and Blood clock. These are advanced epigenetic clocks: GrimAge2 was designed to predict future morbidity and mortality risk, while FitAge integrate fitness metrics into its estimates. The Skin and Blood clock, as its name implies, was designed using data from skin and blood cells.

The study found that immediately after games, there were significant decreases in biological age predictors: on average, DNAmGrimAge2 age predictions decreased by 32%, DNAmFitAge by 18%, and Skin and Blood by 24% compared to their estimates before the games. Predictions returned to normal after a period of rest. By contrast, there was no significant before and after difference in the control group. There was also a significant drop in certain inflammatory molecules post-game, as well as significant changes in white blood cell composition.

Looking at the above graphs, you might notice that while epigenetic age was lower post-game for most players, some players saw a rise in their measured epigenetic age. Interestingly, these players were more likely to suffer injuries later on, though this trend wasn’t statistically significant.

The implications:

Of course, this study is not suggesting that players became 32% younger for a while after each match, so what happened here? This research highlights the fact that epigenetic clocks are proxies – they don’t literally measure biological age, in much the same way that blood pressure is not synonymous with cardiovascular health. Blood pressure can vary for many reasons, but it is still useful as marker for cardiovascular health. The same can probably be said for epigenetic clocks when it comes to biological ageing, but some caution has to be applied.

As for why players had lower biological age measurements post-exercise, DNA used to measure epigenetic age comes mostly from white blood cells. It’s likely that changes in the proportions of different types of cell contributed to the measurements. This was also given as a potential explanation in the study we mentioned at the start, which found that epigenetic age was often measured to be lower at night. However, short term epigenetic modifications within the same cell types were also found to be a contributing factor in both studies.

This research could have some practical implications for elite sports if the relationship between epigenetic age and injury is found to be statistically significant in a larger sample size. A rise in epigenetic age post-game could be used to predict higher risk of injury, or it could indicate that a player’s training needs to be adjusted.