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Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer
PURPOSE: The time-of-day variations in environmental heat stress have been known to affect thermoregulatory responses and the risk of exertional heat-related illness during outdoor exercise in the heat. However, such effect and risk are still needed to be examined during indoor sports/exercises. The...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707556/ https://www.ncbi.nlm.nih.gov/pubmed/33259509 http://dx.doi.org/10.1371/journal.pone.0242916 |
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author | Otani, Hidenori Goto, Takayuki Kobayashi, Yuki Shirato, Minayuki Goto, Heita Hosokawa, Yuri Tokizawa, Ken Kaya, Mitsuharu |
author_facet | Otani, Hidenori Goto, Takayuki Kobayashi, Yuki Shirato, Minayuki Goto, Heita Hosokawa, Yuri Tokizawa, Ken Kaya, Mitsuharu |
author_sort | Otani, Hidenori |
collection | PubMed |
description | PURPOSE: The time-of-day variations in environmental heat stress have been known to affect thermoregulatory responses and the risk of exertional heat-related illness during outdoor exercise in the heat. However, such effect and risk are still needed to be examined during indoor sports/exercises. The current study investigated the diurnal relationships between thermoregulatory strain and environmental heat stress during regular judo training in a judo training facility without air conditioning on a clear day in the heat of summer. METHODS: Eight male high school judokas completed two 2.5-h indoor judo training sessions. The sessions were commenced at 09:00 h (AM) and 16:00 h (PM) on separate days. RESULTS: During the sessions, indoor and outdoor heat stress progressively increased in AM but decreased in PM, and indoor heat stress was less in AM than PM (mean ambient temperature: AM 32.7±0.4°C; PM 34.4±1.0°C, P<0.01). Mean skin temperature was higher in AM than PM (P<0.05), despite greater dry and evaporative heat losses in AM than PM (P<0.001). Infrared tympanic temperature, heart rate and thermal sensation demonstrated a trial by time interaction (P<0.001) with no differences at any time point between trials, showing relatively higher responses in these variables in PM compared to AM during the early stages of training and in AM compared to PM during the later stages of training. There were no differences between trials in body mass loss and rating of perceived exertion. CONCLUSIONS: This study indicates a greater thermoregulatory strain in the morning from 09:00 h than the late afternoon from 16:00 h during 2.5-h regular judo training in no air conditioning facility on a clear day in the heat of summer. This observation is associated with a progressive increase in indoor and outdoor heat stress in the morning, despite a less indoor heat stress in the morning than the afternoon. |
format | Online Article Text |
id | pubmed-7707556 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-77075562020-12-08 Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer Otani, Hidenori Goto, Takayuki Kobayashi, Yuki Shirato, Minayuki Goto, Heita Hosokawa, Yuri Tokizawa, Ken Kaya, Mitsuharu PLoS One Research Article PURPOSE: The time-of-day variations in environmental heat stress have been known to affect thermoregulatory responses and the risk of exertional heat-related illness during outdoor exercise in the heat. However, such effect and risk are still needed to be examined during indoor sports/exercises. The current study investigated the diurnal relationships between thermoregulatory strain and environmental heat stress during regular judo training in a judo training facility without air conditioning on a clear day in the heat of summer. METHODS: Eight male high school judokas completed two 2.5-h indoor judo training sessions. The sessions were commenced at 09:00 h (AM) and 16:00 h (PM) on separate days. RESULTS: During the sessions, indoor and outdoor heat stress progressively increased in AM but decreased in PM, and indoor heat stress was less in AM than PM (mean ambient temperature: AM 32.7±0.4°C; PM 34.4±1.0°C, P<0.01). Mean skin temperature was higher in AM than PM (P<0.05), despite greater dry and evaporative heat losses in AM than PM (P<0.001). Infrared tympanic temperature, heart rate and thermal sensation demonstrated a trial by time interaction (P<0.001) with no differences at any time point between trials, showing relatively higher responses in these variables in PM compared to AM during the early stages of training and in AM compared to PM during the later stages of training. There were no differences between trials in body mass loss and rating of perceived exertion. CONCLUSIONS: This study indicates a greater thermoregulatory strain in the morning from 09:00 h than the late afternoon from 16:00 h during 2.5-h regular judo training in no air conditioning facility on a clear day in the heat of summer. This observation is associated with a progressive increase in indoor and outdoor heat stress in the morning, despite a less indoor heat stress in the morning than the afternoon. Public Library of Science 2020-12-01 /pmc/articles/PMC7707556/ /pubmed/33259509 http://dx.doi.org/10.1371/journal.pone.0242916 Text en © 2020 Otani et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Otani, Hidenori Goto, Takayuki Kobayashi, Yuki Shirato, Minayuki Goto, Heita Hosokawa, Yuri Tokizawa, Ken Kaya, Mitsuharu Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer |
title | Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer |
title_full | Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer |
title_fullStr | Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer |
title_full_unstemmed | Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer |
title_short | Greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer |
title_sort | greater thermoregulatory strain in the morning than late afternoon during judo training in the heat of summer |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707556/ https://www.ncbi.nlm.nih.gov/pubmed/33259509 http://dx.doi.org/10.1371/journal.pone.0242916 |
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