Active people could be up to 10 years ‘younger’ than couch potatoes, at least according to one measure of biological age. Tim Spector, director of the Twin Research Unit at St Thomas’ Hospital in London, looked at the levels of physical activity of 2,401 twins and assessed the length of their telomeres – the ‘caps’ on the ends of their chromosomes that help to protect the DNA from wearing down during the replication process that replenishes cells. Telomeres shorten over an individual’s lifetime and are thought to function as a marker for ageing. Smokers and obese people were already known to have shorter telomeres than their healthier counterparts.
The team found that, on average, telomeres in the most active group (who took more than 3 hours 20 minutes of exercise a week) were 200 nucleotides longer than that of the least active group (who took less than 16 minutes exercise a week). “This difference suggests that inactive subjects may be biologically older by 10 years compared with more active subjects,” say Spector and colleagues in their paper in Archives of Internal Medicine.