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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Exercise Physiology
Volume 15 - 2024 | doi: 10.3389/fphys.2024.1473241
This article is part of the Research Topic Acute and Chronic Responses to Heat Stress to Optimize Health and Performance View all 3 articles

The combined influences of local heat application and resistance exercise on the acute mRNA response of skeletal muscle

Provisionally accepted
Mark L. McGlynn Mark L. McGlynn 1Alejandro M. Rosales Alejandro M. Rosales 2Christopher W. Collins Christopher W. Collins 1Dustin R. Slivka Dustin R. Slivka 2*
  • 1 University of Nebraska Omaha, Omaha, United States
  • 2 University of Montana, Missoula, Montana, United States

The final, formatted version of the article will be published soon.

    The development and maintenance of skeletal muscle is crucial for the support of daily function. Heat, when applied locally, has shown substantial promise in the maintenance of muscle. The purpose was to determine the combined effects of local heat application and acute resistance exercise on gene expression associated with the human muscle growth program. Participants (n=12, 26±7 yr, 1.77±0.07 m, 79.6±15.4 kg, 16.1±11.6 %BF) completed an acute bilateral bout of resistance exercise consisting of leg press (11±2 reps, 170±37 kg) and leg extension (11±1 reps, 58±18 kg). Participants wore a thermal wrap containing circulating fluid (40°C, exercise + heat; EX+HT) during the entire experimental period and 4 h post-exercise, while the other leg served as an exercise-only (EX) control. Biopsies of the vastus lateralis were collected (Pre, Post, and 4hPost) for gene expression analyses. Intramuscular temperatures increased (Post, +2.2±0.7°C, p<0.001; 4hPost, +2.5±0.6°C, p<0.001) and were greater within the EX+HT leg post-exercise (+0.35±0.3°C, p=0.005) and after 4hPost (+2.1±0.8°C, p<0.001). MYOD1 mRNA was greater within the EX+HT leg vs. the EX (fold change=2.74±0.42, vs. 1.70±0.28, p=0.037). No other genes demonstrated temperature sensitivity between legs (p>0.05). mRNA associated with the negative regulator, myostatin (MSTN), decreased post-exercise (p=0.001) and after 4 h (p=0.001). mRNA associated with proteolysis decreased postexercise (FBXO32, p=0.001; FOXO3a, p=0.001) and after 4 h (FBXO32, p=0.001; FOXO3a, p=0.027). The elevated transcription of the myogenic differentiating factor 1 (MYOD1) after exercise in the heated condition may provide a mechanism by which muscle growth could be enhanced.

    Keywords: myogenic, Proteolytic, Gene Expression, Myostatin, Myogenin, MYO-D1

    Received: 30 Jul 2024; Accepted: 23 Sep 2024.

    Copyright: © 2024 McGlynn, Rosales, Collins and Slivka. 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) or licensor 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: Dustin R. Slivka, University of Montana, Missoula, 59812, Montana, United States

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.