RT Journal Article SR Electronic T1 Stand up for health—avoiding sedentary behaviour might lengthen your telomeres: secondary outcomes from a physical activity RCT in older people JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 1407 OP 1409 DO 10.1136/bjsports-2013-093342 VO 48 IS 19 A1 Per Sjögren A1 Rachel Fisher A1 Lena Kallings A1 Ulrika Svenson A1 Göran Roos A1 Mai-Lis Hellénius YR 2014 UL http://bjsm.bmj.com/content/48/19/1407.abstract AB Background Telomere length has been associated with a healthy lifestyle and longevity. However, the effect of increased physical activity on telomere length is still unknown. Therefore, the aim was to study the relationship between changes in physical activity level and sedentary behaviour and changes in telomere length. Methods Telomere length was measured in blood cells 6 months apart in 49, 68-year-old, sedentary, overweight individuals taking part in a randomised controlled physical activity intervention trial. The intervention group received individualised physical activity on prescription. Physical activity was measured with a 7-day diary, questionnaires and a pedometer. Sitting time was measured with the short version of The International Physical Activity Questionnaire. Results Time spent exercising as well as steps per day increased significantly in the intervention group. Reported sitting time decreased in both groups. No significant associations between changes in steps per day and changes in telomere length were noted. In the intervention group, there was a negative correlation between changes in time spent exercising and changes in telomere length (rho=−0.39, p=0.07). On the other hand, in the intervention group, telomere lengthening was significantly associated with reduced sitting time (rho=−0.68, p=0.02). Conclusions Reduced sitting time was associated with telomere lengthening in blood cells in sedentary, overweight 68-year-old individuals participating in a 6-month physical activity intervention trial.