People who are physically active appear to be biologically younger than those who chose a more "couch potato" lifestyle - at least from a cellular point of view, finds news research.
The report, , finds that those who exercise regularly tend to have more robust DNA than those who don't.
"Looking into our cells is actually a window into how our bodies are aging," said researcher Elissa Epel. "So cell aging is linked to how quickly we get disease and how long we live."
The study was conducted on 2,401 white twins, who answered questionnaires on their exercise levels, and also provided a blood sample from which DNA was extracted.
The researchers looked at the length of the twins' telomeres--the little protective caps at the end of the chromosomes of white blood cells (leukocytes). It's known that leukocyte telomeres progressively shorten over time and are seen as a marker of biological age.
The researchers, led by Lynn F. Cherkas, of King's College London, found that men and women who were less physically active had shorter leukocyte telomeres than those who were more active.
In fact, the difference between those who were the most active (those did an average of 199 minutes of physical activity per week) and those who were least active (who did an average 16 minutes of physical activity per week) as 200 nucleotides (which are the structural units of chromosomes.
That means that the most active subjects had telomeres the same length as sedentary individuals up to 10 years younger, on average.
The researchers think that exercise helps reduce oxidative stress to cells as well as inflammation, which also damages cells over time. As well, physical activity may reduce psychological stress, which has also been shown to reduce telomere length.
"Such a relationship between leukocyte telomere length and physical activity level remained significant after adjustment for body mass index, smoking, socioeconomic status and physical
Oxidative stress--damage caused to cells by exposure to oxygen--and inflammation are likely mechanisms by which sedentary lifestyles shorten telomeres, the authors suggest. In addition, perceived stress levels have been linked to telomere length. Physical activity may reduce psychological stress, thus mitigating its effect on telomeres and the aging process.
The findings are further evidence of why exercising moderately for 30 minutes a day, at least five days a week is so important, the authors write.
"Our results underscore the vital importance of these guidelines. They show that adults who partake in regular physical activity are biologically younger than sedentary individuals."
With a report by CTV's Todd Battis in Vancouver
