Couch potato lifestyle may speed up ageing

[29 January 2008 - New Scientist] Being a couch potato in your free time could make you a decade older biologically than someone who is physically active, according to a major study of people's "chromosomal clocks". Tim Spector at St Thomas’ hospital in London, UK, and colleagues measured the lengths of telomeres – the DNA that bookends our chromosomes – in the white blood cells of 2401 twins. Telomeres shorten each time a cell divides, and when they become too short a cell can no longer divide, so telomeres act as a kind of timer counting down our biological age. The researchers found that people who did not exercise in their spare time had shorter telomeres than very active people. ... David Gems, who researches ageing, at University College London, notes: "These days older folks spend more and more money on various dietary supplements in the hope of ageing more slowly, but really they would be better off keeping the money and just walking the dog more often". More