Effect of different levels of exercise on telomere length: A systematic review and meta-analysis

To investigate the effect of different levels of exercise on telomere length.

CINAHL, SPORTDiscus (EBSCO), OVID (Medline) and EMBASE databases were searched for eligible studies. Methodological quality was evaluated using the Newcastle-Ottawa Scale, and heterogeneity among the studies was assessed using the I-squared test. When heterogeneity among studies was high (I2 > 50%), a random-effects model was used (Review Manager version 5, Cochrane Collaboration, Copenhagen, Denmark); otherwise, a fixed-effects model was used.

Eleven eligible studies involving 19,292 participants were included in this meta-analysis. Longer telomere length was associated with physically active individuals, with a mean difference (MD) of 0.15 (95% confidence interval; 95% CI 0.05, 0.24); I2 = 99%. Longer telomere length was significantly associated with robust exercise (MD 0.08 (95% CI 0.04, 0.12)); I2 = 99%, as was moderate exercise (MD 0.07 (95% CI 0.03, 0.11)); I2 = 100%. Subgroup analysis revealed that longer telomere length was positively associated with exercise, regardless of sex, but was not statistically significant in elderly populations.

Compared with inactive individuals, telomere lengths were longer in active subjects, regardless of the intensity of exercise.