A Systematic Review of the Association Between Muscular Fitness and Telomere Length Across the Adult Lifespan.

Adilson Marques,Gerson Ferrari,Priscila Marconcin,Duarte Henriques-Neto,Andreas Ihle,Miguel Peralta,Élvio Rúbio Gouveia,João Martins,Hugo Sarmento

doi:10.3389/fphys.2021.706189

Abstract

This study aimed to systematically review the association between telomere length (TL) and muscular fitness. In October 2020, an articles search was applied to PubMed, Scopus, and Web of Science. Eligibility criteria included: cross-sectional, prospective, and experimental study design; outcomes included TL; results expressed the relationship between muscular fitness and TL; studies published in English, Portuguese, or Spanish. Nine studies were included in the review. Results from the four prospective studies are mixed. In one study, the changes in TL were associated with grip strength. Another study concluded that longer mid-life TL was associated with increased grip strength later in life. However, in the other two studies, the association between TL and sarcopenia was not strong. Nevertheless, longer TL was associated with a slower decline in grip strength in older people. From the four cross-sectional studies, three indicated that TL was associated with muscular fitness. On the other hand, in a study with powerlifters, TL remained within the range of values found in subjects with no history of regular strength training, supporting the notion that muscular fitness was not associated with TL. The cross-sectional and prospective studies showed that the relationship between TL and muscular fitness is not conclusive. It seems that there is a positive association between TL and muscular fitness in middle-aged and older adults. However, among younger adults, this relationship was not observed.

Highlights

Chromosome ends are protected by tandem repeats of hexanucleotide units named telomeres (Lu et al, 2013)
Nine studies examining the association between muscular fitness and Telomere length (TL) were identified
Five studies reported that TL was positively associated with muscular fitness, including gait speed, grip strength, lower extremity muscular strength, fat-free mass, and thigh muscle area

Summary

Introduction

Chromosome ends are protected by tandem repeats of hexanucleotide units named telomeres (Lu et al, 2013). Telomeres are critical in regulating cellular replicative capacity (Codd et al, 2013). The telomeres shorten each time a cell divides because of the inability of the DNA polymerase to replicate the ends of the linear molecules completely. Telomere length (TL) shortening is associated with cellular senescence (Liu et al, 2019), oxidative stress (Mundstock et al, 2015a), increased inflammatory process (Arsenis et al, 2017), tobacco smoking, alcohol consumption, and physical activity (Mather et al, 2010; Codd et al, 2013; Lin et al, 2019). TL shortening is not an irreversible process because of telomerase, an enzyme capable of extending telomeres. TL in skeletal muscle can be considered more dynamic structures under the influence of the environment, such as physical activity, exercise, and physical fitness (Kadi and Ponsot, 2010)

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