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 chromosomes that help to protect the DNA. Telomeres shorten over an individual’s lifetime and are thought to be a marker for ageing. Smokers and obese people are 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.
The researchers also looked at matched pairs of twins and found an average difference of 88 nucleotides between the more and less active siblings.
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They don't know why. They looked only at exercise in the previous 12 months, not life history. And I don't know what they count as "exercise" -- for example, does walking count?
I'm currently doing about three and a half hours of running a week.
