DNA =?= Causality
You can get DNA samples and you can measure telomeres, but you still can’t measure causality.
I haven’t read the original article, that that’s beside the point. Talking about semiotics, DNA represents the ultimate causality in popular thinking and media reporting. In this case, do stressed folks get less physical activities, or does activities reduce stress? Can you read that off the DNA?
Sedentary Lifestyle Accelerates Aging - washingtonpost.com
"A sedentary lifestyle increases the propensity to aging-related diseases and premature death. Inactivity may diminish life expectancy not only by predisposing to aging-related diseases, but also because it may influence the aging process itself," study author Lynn F. Cherkas, of King’s College London, said in a prepared statement. The researchers looked at the physical activity levels, smoking habits and socioeconomic status of 2,401 white twins. The researchers also collected DNA samples from participants, and examined the length of telomeres-repeated sequences at the end of chromosomes in white blood cells (leukocytes). Leukocyte telomeres shorten over time and may serve as a marker of a person’s biological age. Overall, the study participants had an average telomere loss of 21 nucleotides (structural units) per year. But those who were more active in their leisure time had longer leukocyte telomeres than those who were less active.