Telomere length and cardiorespiratory fitness in marathon runners.
Level 4 - case-series / case-control
Case-control observational study with matched controls
PubMed 23360839 · doi:10.2310/JIM.0b013e3182814cc2
What was done
A matched case-control study compared 17 marathon runners with 15 age- and sex-matched healthy sedentary controls. Investigators assessed medical history, demographics, maximal oxygen uptake (VO2 max) as an objective measure of cardiorespiratory fitness, and telomere length in peripheral blood lymphocytes and granulocytes. Linear regression was conducted to identify associations between telomere length and measured variables.
What was found
Lymphocyte telomere length was similar between marathon runners and sedentary controls (0.97 ± 0.20 vs 1.01 ± 0.18; P = 0.6). Granulocyte telomere length was also equivalent (0.89 ± 0.11 vs 0.89 ± 0.12; P = 0.9). There was no correlation between VO2 max and telomere length. Age was the only variable significantly associated with telomere length in linear regression analysis (P = 0.007).
Why it matters
This study adds objective fitness measurements to the literature, showing that high aerobic fitness from endurance training is not associated with longer leukocyte telomeres relative to sedentary living.
Limits
The sample size was very small (32 participants), limiting statistical power. The cross-sectional design cannot evaluate longitudinal telomere attrition, and measurements were restricted to circulating leukocytes rather than muscle or other tissues.
Cited by
- supports The relationship between exercise volume/intensity and telomere length is non-linear, with marathon runners exhibiting only slightly longer telomeres than moderate regular runners.