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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Physiol. | doi: 10.3389/fphys.2019.01123

Multi-day prolonged low- to moderate-intensity endurance exercise mimics training improvements in metabolic and oxidative profiles without concurrent chromosomal changes in healthy adults

 Dominique D. Gagnon1, 2*,  Sandra Dorman1, 2, 3, Stephen Ritchie2, 4,  Shivaprakash Jagalur Mutt5,  Ville Stenbäck5, Jarosław Walkowiak6 and  Karl-Heinz Herzig5, 6
  • 1School of Human Kinetics, Laboratory of Environmental Physiology, Laurentian University, Canada
  • 2Centre for Research in Occupational Safety and Health, Laurentian University, Canada
  • 3Northern Ontario School of Medicine, Canada
  • 4School of Human Kinetics, Laurentian University, Canada
  • 5Biocenter Oulu, University of Oulu, Finland
  • 6Poznan University of Medical Sciences, Poland

Background: Oxidative stress results in lipid, protein and DNA oxidation, resulting in telomere erosion, chromosomal damage, and accelerated cellular aging. Training promotes healthy metabolic and oxidative profiles whereas the effects of multi-day, prolonged and continuous exercise, are unknown. This study investigated the effects of multi-day prolonged exercise on metabolic and oxidative stress as well as telomere integrity in healthy adults.

Methods: Fifteen participants performed a 14-day, 260-km, wilderness canoeing expedition (12 males) (EXP) (24 ± 7 yrs, 72 ± 6 kg, 178 ± 8.0 cm, 18.4 ± 8.4 %BF, 47.5 ± 9.3 mlO2·kg-1·min-1), requiring 6-9 hrs of low- to moderate-intensity exercise daily. Ten controls participated locally (7 males) (CON) (31 ± 11 yrs, 72 ± 15 kg, 174 ± 10 cm, 22.8 ± 10.0 %BF, 47.1 ± 9.0 mlO2·kg-1·min-1). Blood plasma, serum, and mononuclear cells were sampled before and after the expedition to assess hormonal, metabolic, and oxidative changes.

Results: Serum cholesterol, high- and low-density lipoprotein, testosterone, insulin, sodium, potassium, urea and chloride concentrations were not different between groups, whereas triglycerides, glucose, and creatinine levels were lower following the expedition (p < 0.001). Malondialdehyde and relative telomere length were unaffected (EXP: 4.2 ± 1.3 vs. CON: 4.1 ± 0.7 µM; p > 0.05: EXP: 1.00 ± 0.48 vs. CON: 0.89 ± 0.28 TS ratio; p = 0.77, respectively); however, superoxidase dismutase activity was greater in the expedition group (3.1 ± 0.4 vs. 0.8 ± 0.5 U·ml-1; p < 0.001).

Conclusion: These results indicate a modest improvement in metabolic and oxidative profiles with increased superoxidase dismutase levels, suggesting an antioxidative response to counteract the exercise-associated production of free radicals and reactive oxygen species during prolonged exercise, mimicking the effects from long-term training. Although improved antioxidant activity may lead to increased telomere length, the present exercise stimulus was insufficient to promote a positive cellular aging profile with concordant chromosomal changes in our healthy and young participants.

Keywords: telomeres, Oxidative Stress, Hormones, Metabolism, Exercise

Received: 13 Dec 2018; Accepted: 14 Aug 2019.

Copyright: © 2019 Gagnon, Dorman, Ritchie, Jagalur Mutt, Stenbäck, Walkowiak and Herzig. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Dominique D. Gagnon, Laurentian University, School of Human Kinetics, Laboratory of Environmental Physiology, Greater Sudbury, Canada, ddgagnon@laurentian.ca