The impact of exercise on DNA and telomere length
Telomeres are a hot topic in current research for aging and biological changes. Telomeres can be figuratively thought of as the 'caps' at the end of a shoe lace (with the lacing representing DNA chromosomes). Telomeres protect chromosomes from degeneration, but it is known that this protective length decreases with age. This article aims to explore various types of physical activity and its impacts on telomere length, and how exercise can help resist telomere shortening through the natural aging process.
The authors conducted a PubMed literature search, and examined 21 articles relating to telomere length and physical activity, published between 1998-2016. Various types of telomeres were discussed, including skeletal muscle, leukocyte, peripheral blood mononuclear cells (PBMCs), and satellite cell telomeres.
Most research to date has compared telomere length in active vs. sedentary populations. However, this review examined various forms of exercises and comparing lenght of training time. The research findings were not conclusive for one type or duration of exercise supporting increased telomere length. With regard to skeletal muscle telomeres, shorter lengths in telomeres were found in runners with longer training hours than those with shorter hours. However, in powerlifters, longer telomeres were recorded as compared to those who did not lift weights.
This article discussed leukocyte telomeres, as leukocytes are a protective part of the immune sytem, and the authors note leukocyte telomere may be associated with years of healthy living. In this review, 12 of 18 articles reviewed looking at leukocyte telomere length and some form of exercise showed a positive correlation. However, the remaining 6 articles were not conclusive for supporting exercise as a means for protecting leukocyte telomere length.
PBMCs, regarded as any blood cell with a round nucleus, were also examined in one of the reviewed studies and it was noted that moderate activity may be as effective as vigorous exercise in preserving telomere length.
Satellite cells, important for the regeneration of skeletal muscle cells, are known to decrease with age, particularly after age 70. However, this article notes that physical exercise serves as a mode to protect against age-related decline of satellite cells, and as a result a protectant of skeletal muscle. Thus, exercise may indirectly prevent decline in skeletal muscle telomeres via enhancement of satellite cells.
The positive effects of exercise are widely known to be biologically beneficial to the human body. While the reviewed research in this literature review is not fully conclusive in noting a direct correlation of one specific type and duration of exercise, it lends to the hypothesis that exercise does have a positive and potentially protectant factor on telomeres, and thus on chromosomal degeneration.
> From: Arsenis et al., Oncotarget (2017) 16726(Epub ahead of print). All rights reserved to Oncotarget. Click here for the online summary.