Telomeres are tandem repeat DNA sequences located at distal ends of chromosomes that protect against genomic DNA degradation and chromosomal instability. Excessive telomere shortening leads to cellular senescence and for this reason telomere length is a marker of biological age. Abnormally short telomeres may culminate in the manifestation of a number of cardio-metabolic diseases. Age-related cardio-metabolic diseases attributable to an inactive lifestyle, such as obesity, type 2 diabetes mellitus and cardiovascular disease, are associated with short leukocyte telomeres. Exercise training prevents and manages the symptoms of many cardio-metabolic diseases whilst concurrently maintaining telomere length. The positive relationship between exercise training, physical fitness and telomere length raises the possibility of a mediating role of telomeres in chronic disease prevention via exercise. Further elucidation of the underpinning molecular mechanisms of how exercise maintains telomere length should provide crucial information on how physical activity can be best structured to combat the chronic disease epidemic and improve the human health span. Here, we synthesise and discuss the current evidence on the impact of physical activity and cardiorespiratory fitness on telomere dynamics. We provide the molecular mechanisms with a known role in exercise-induced telomere length maintenance and highlight unexplored, alternative pathways ripe for future investigations.
The authors would like to express their gratitude to the Federation University Australia “Self-sustaining Regions Research and Innovation Initiative”, an Australian Government Collaborative Research Network (CRN).
Joshua Denham is supported by an Australian Post-graduate Award scholarship. Fadi Charchar is supported by the Lew Carty Charitable fund and National Health and Medical Research Council. No other sources of funding were used to assist in the preparation of this article.
Joshua Denham, Brendan O’Brien and Fadi Charchar declare that they have no conflicts of interest relevant to the content of this review.