Observational Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Psychiatry. May 19, 2023; 13(5): 234-246
Published online May 19, 2023. doi: 10.5498/wjp.v13.i5.234
Associations between Borg’s rating of perceived exertion and changes in urinary organic acid metabolites after outdoor weight-bearing hiking
Pei-Pei Sang, Jin Li, Xu-Dong Tan, Wei Peng, Hong-Hui Zhou, Ya-Ping Tian, Man-Li Zhang
Pei-Pei Sang, Jin Li, Xu-Dong Tan, Wei Peng, Hong-Hui Zhou, Ya-Ping Tian, Man-Li Zhang, Birth Defect Prevention and Control Technology Research Center, Medicine Innovation Research Division, Chinese PLA General Hospital, Beijing 100853, China
Author contributions: Sang PP and Zhang ML designed the study; Sang PP, Li J, Tan XD and Peng W performed the research; Sang PP and Zhou HH analyzed the data; Sang PP wrote the paper; and Tian YP and Zhang ML revised the manuscript for final submission.
Supported by the National Key Research and Development Program of China, No. 2020YFC2004604 and 2020YFC2002700.
Institutional review board statement: The study was reviewed and approved by the Chinese PLA General Hospital Review Board (Approval No. S2021-019-01).
Informed consent statement: All participants signed the informed consent form.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: No data were shared.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Man-Li Zhang, MD, Associate Chief Physician, Birth Defect Prevention and Control Technology Research Center, Medicine Innovation Research Division, Chinese PLA General Hospital, No. 28 Fuxing Road, Haidian District, Beijing 100853, China. zhangmanli1982@126.com
Received: March 9, 2023
Peer-review started: March 9, 2023
First decision: March 23, 2023
Revised: March 31, 2023
Accepted: April 7, 2023
Article in press: April 7, 2023
Published online: May 19, 2023
Processing time: 71 Days and 2.8 Hours
Abstract
BACKGROUND

Developing methods to monitor exercise load and evaluate body fatigue and muscle injury over time in hiking training remains a key problem to be solved. A widely used psycho-physical tool to assess the subjective perception of effort during exercise is Borg’s rating of perceived exertion (BRPE) scale. Data on the relationships and validity of the BRPE compared to objectively assessed metabolic criteria are still lacking, especially urinary organic acid concentrations.

AIM

To verify whether the BRPE scale could be used in the prescription of outdoor hiking with weight-bearing and reveal the relationship between the BRPE scale and urinary physiological measures.

METHODS

Eighty-nine healthy men (average age: 22 years) were enrolled in a 40 km (6 h) hiking training exercise with a 20 kg load. After training, the BRPE scale (6-20) was completed. All participants were divided into three groups according to the rating of the BRPE scale. Urine samples were collected before and after training. Urinary myoglobin levels were measured immediately using the fluorescent immunoassay method. The remaining urine was subpacked and frozen for the subsequent detection of urinary organic acids using gas chromatography and mass spectrometry.

RESULTS

The contents of organic acids and myoglobin in urine were significantly increased after participants hiked 40 km (6 h) with a 20 kg load. Only orthogonal partial least-squares discrimination analysis performed well in separating the group with a BRPE score of 6-12 from the group with a BRPE score of 13-20. Significant differences in the urine levels of several organic acids were observed between the two groups, and the heatmap also presented different metabolic profiles based on BRPE. According to the standard of a variable importance in the projection > 1, fold change > 1.5 and P < 0.05, 19 different metabolites of urinary organic acids were screened and enriched in pathways mainly including the citrate cycle (tricarboxylic acid cycle) and alanine, aspartate and glucose metabolism.

CONCLUSION

The BRPE scale identified significantly different urinary organic acid profiles between the higher and lower BRPE value groups, and, thus, could be used to monitor body fatigue in individuals participating in long-distance outdoor hiking with weight bearing.

Keywords: Borg’s rating of perceived exertion; Urine; Organic acid metabolism; Exercise intensity; Myoglobin; Hiking

Core Tip: Developing methods to monitor exercise load and evaluate body fatigue over time in endurance training is a key problem to be solved. Borg’s rating of perceived exertion (BRPE) scale has been widely used as a psycho-physical tool to assess the subjective perception of effort during exercise. In this study, we aimed to verify whether the BRPE scale could be used in the prescription of outdoor hiking with weight-bearing and reveal the relationship between the BRPE scale and urinary physiological measures, particularly urinary organic acid concentrations. Underlying mechanisms related to body fatigue and metabolic disorders were also analyzed in this study.