Effect of different levels of exercise on telomere length
includes breathing exercises and meditation, was also
found to be positively associated with telomere length.
Breathing exercises and meditative components have
been shown to have positive effects on psychological
health, including alleviation of stress, anxiety and
depression, which are significantly associated with
shortened telomere length (50, 51).
In addition, in subgroup analysis according to age, the
current study found that exercise had a positive effect
on leukocyte telomere length in younger individuals,
but not in elderly subjects. Some researchers found that
exercise did not positively affect leukocyte telomere
length in a group of young subjects (33, 38). However,
another study involving healthy adolescents found that
exercise resulted in increased leukocyte telomere length
(51). This discrepancy may be attributed to differences
in sample size and methods of telomere measurement
and, perhaps, selection bias in these studies.
The current study has several limitations that should
be addressed. First, the strength of evidence may be
weakened due to deficiency of data in some studies,
and differences in tissue sources, sample size and
methods of evaluation of telomeres. Secondly, it was
not possible to perform formal subgroup analysis ac-
cording to age, except for the elderly group, because
age varied widely across the included studies. Thus, the
current study could not provide sufficient evidence to
support the association between exercise and telomere
length according to age. Finally, the pooled synthesis
of observational studies in this meta-analysis may have
limited the quality of evidence compared with larger,
randomized controlled trials.
Conclusion
Compared with inactive individuals, active subjects
had longer telomere lengths, especially those who
engaged in moderate and robust physical exercise.
Further prospective, large, randomized controlled
studies are needed to determine the effect of different
types of physical activity on telomere length.
ACKNOWLEDGEMENTS
The authors thank the staff of the National Clinical Research
Center of Geriatrics, West China Hospital, Sichuan University,
Chengdu, Sichuan Province, China.
The authors have no conflicts of interest to declare.
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