Aging Is Easier with Endurance Exercise
Among individuals ages 66 to 77, endurance athletes had significantly longer telomeres compared with their less active counterparts (P=0.04), a relationship that was not seen among individuals in their 20s, according to Javaid Nauman, PhD, of the Norwegian University of Science and Technology in Trondheim, and colleagues.
The results "suggest that endurance exercise training may regulate the telomeres in old age and results in slowing of [the] aging process by maintaining telomere length," the authors wrote in online in PLOS ONE.
They noted, however, that the findings, which were based on a small sample of just 20 individuals, should be considered preliminary and interpreted cautiously.
Telomeres shorten over time as cells continue to reproduce. Telomere length has been related to both cellular age and the physical aging process. Studies examining the association between telomere length and exercise training and capacity have yielded inconsistent results.
To explore the issue, the researchers recruited 20 men, half of whom were ages 22 to 27 (mean age about 24) and the other half ages 66 to 77 (mean age about 69). In each age group, half of the participants were endurance athletes who were taking part in a cross-country ski race or track competitions. The others were nonathletes who were active, but who had never competed at higher levels in any sports.
All of the participants were free from known cardiovascular disease, obesity, and a history of current or past smoking. None was taking regular medications.
After muscle biopsies, mean telomere length was assessed using the ratio of the telomere repeat copy number to the single-gene copy number (T/S ratio) as measured by quantitative real-time polymerase chain reaction. Maximal oxygen consumption (VO2max) was measured as the participants ran on a treadmill.
In the older age group, the endurance athletes had significantly longer telomeres (T/S ratio 1.12 versus 0.92, P=0.04), a difference that might have clinical significance in terms of longevity, according to the researchers.
"However," they added, "the design of the present study being cross-sectional in nature does not allow commenting about the causality of these results."
In the younger age group, telomere length was not significantly different between the endurance athletes and the nonathletes (T/S ratio 1.47 versus 1.33, P=0.12), possibly because of the small sample size or shorter exposure to physical activity.
Exercise capacity as measured by VO2max was higher for the endurance athletes both in the younger age group (67 versus 53.9 mL/kg/min) and the older age group (45.4 versus 39.4 mL/kg/min).
In the overall cohort, telomere length was positively associated with VO2max (r=0.70, P=0.001). The relationship was stronger among the endurance athletes (r=0.78, P=0.02) and fell short of statistical significance among the nonathletes (r=0.58, P=0.09).
Those findings "provide further support to the hypothesis that long-term exercise, higher aerobic fitness, and longer telomeres all are part of same phenotype expressed in some older adults," the authors wrote.
Besides the small sample size, they acknowledged other study limitations, including the inclusion of males only and the possibility of residual confounding by unknown or unmeasured factors.
The
study was supported by grants from the K.G. Jebsen Foundation, the
Faculty of Medicine, Norwegian University of Science and Technology.
The authors reported no conflicts of interest.
The authors reported no conflicts of interest.
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