Effect of physical activity and exercise on telomere length: Systematic review with meta‐analysis

Abstract

To compare a physically active lifestyle or structured exercise program to physically inactive lifestyle or control groups on telomere length (TL). Method: We searched PubMed, EMBASE, Cochrane Library, and Open Gray databases up to March 31, 2020. We calculated standardized mean differences (SMD) with 95% confidence intervals (CI) of TL comparing physically active to physically inactive individuals and exercise intervention to control groups. Risk of bias was judged using the Risk of Bias Assessment tool for Non-randomized Studies (RoBANS) for physical activity (PA) studies and the Cochrane risk-of-bias (RoB2) for exercise intervention studies. Certainty of evidence was judged using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Results:We included 30 studies (24 assessing the effects of PA and 6 assessing the effects of exercise interventions) comprising 7418 individuals. Physically active individuals had longer telomeres (SMD = 0.70, 95% CI 0.12-1.28, verylow certainty), especially in middle-aged individuals (SMD = 0.90, 95% CI 0.08-1.72, very-low certainty) and when considering only athletes (SMD = 0.54, 95% CI 0.18-0.90, very-low certainty). Trim-and-fill analyses revealed that most of See related Editorial by Pignolo et al. in this issue.

Investigation of a UK biobank cohort reveals causal associations of self-reported walking pace with telomere length

“…Interestingly, the suggested causal effect of walking pace on LTL via MR was greater than that suggested by the adjusted observational associations reported in this study, or for exercise intervention studies in middle aged adults 28 . We have previously shown that each additional year in chronological age is associated with a Z-standardised LTL value of −0.024 39 .…”

“…A randomised controlled trial in 68 caregivers (as a model of high exposure to stress) also found that 40 minutes of moderate-intensity aerobic exercise 3–5 times per week reduced LTL attrition compared to those in the control group 30 . Further, a recent meta-analysis of case control and intervention studies suggested that, across 21 included studies, the effect of exercise training produced a moderate effect size (0.7), with exercise associated with longer telomeres 28 ; however, associations were no longer statistically significant after accounting for publication bias and stratification/subgrouping. These findings are also supported by mechanistic studies in animal models showing that chronic exercising induced increases in telomere binding proteins (shelterin) and telomerase enzyme activity 31 – 33 .…”

“…Previous research suggests an association of higher levels of physical activity and cardiorespiratory fitness with longer LTL 26 , 27 , supporting the hypothesis that higher levels of physical activity and cardiorespiratory fitness may act to slow markers of biological ageing. However, most human studies to date have been small and/or observational in nature, with some studies showing weak or inconsistent associations 26 – 28 . As a result, the current literature is not definitive and does not support inferences around causal direction.…”

Do the telomere ends justify the physical means?

“…In the article “Effect of physical activity and exercise on telomere length: systematic review with meta‐analysis,” Valente et al 2 assessed the effects of physical activity (PA) or structured exercise (vs. relatively inactive control groups) on mean TL. A systematic review with meta‐analysis was conducted, employing advanced and rigorous risk of bias and statistical analyses.…”

Modifiable traits, healthy behaviours, and leucocyte telomere length

“…9,10 Many studies have therefore sought to explore the relationship between LTL and a range of potentially modifiable environmental and lifestyle factors associated with oxidative stress and inflammation, including smoking, 11,12 obesity, 11,13 diet 14,15 and physical activity. 16,17 However, many of these studies have shown conflicting results, perhaps in part due to moderate sample sizes. Meta-analyses have strengthened the evidence of associations between smoking and higher body mass index (BMI) and shorter LTL.…”