Background: Telomeres are a repeat sequence of DNA (in mammals, TTAGGGn) found at the distal ends of chromosomes that protect genomic integrity. Telomeres gradually shorten with each round of cell division which ultimately reduces tissue vitality. Short leukocyte telomeres are often observed in patients with age-related and degenerative diseases, and accelerated telomere shortening is associated with adverse lifestyle factors, such as psychological distress. Telomerase is an enzyme capable of lengthening telomeres. To that end, we conducted a systematic review and meta-analysis to determine the effects of acute exercise and chronic exercise training on telomerase reverse transcriptase (TERT) gene and telomerase enzyme activity in healthy humans and rodents.
Methods: We conducted a systematic review and meta-analysis as per the PRISMA guidelines. A comprehensive search of the available literature involving the analysis of the acute and/or chronic exercise training-induced changes in TERT gene and telomerase activity in healthy tissues from humans and rodents was performed using four online databases. Studies were screened according to the inclusion/exclusion criteria before a quality assessment was conducted using the Cochrane risk of bias tool. The meta-analytical procedures were performed using the Review Manager software (version 5.4). We also analysed the TERT gene and telomerase activity in endurance athletes compared to untrained controls from relevant studies.
Results: The meta-analytical findings from the five eligible investigations indicated that acute aerobic exercise leads to a very large increase in TERT gene and telomerase activity (standardised mean difference [SMD]: 1.19, P < .01). The results from ten chronic aerobic exercise training interventions revealed that training induces a small to medium increase in TERT gene and telomerase activity (SMD: 0.31, P < .05). Relative to untrained controls, endurance athletes possessed much higher levels of TERT gene expression and telomerase activity.
Discussion: Exercise training is associated with telomere maintenance in the heart, aorta and leukocytes. Our findings suggest both acute and chronic exercise training, as well as long-term endurance training is associated with up-regulated TERT gene and telomerase activity in healthy cells. Importantly, relatively light aerobic exercise and as little as 20 minutes was associated with increased TERT/telomerase activity. Telomerase regulation likely underpins the attenuated telomere attrition associated with exercise training in humans and rodents.
Conflict of interest statement: My co-author and I acknowledge we have no conflict of interest of relevance to the submission of this abstract.