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Low-intensity exercise delays the shivering response to core cooling
- Source :
- American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 316:R535-R542
- Publication Year :
- 2019
- Publisher :
- American Physiological Society, 2019.
-
Abstract
- Hypothermia can occur during aquatic exercise despite production of significant amounts of heat by the active muscles. Because the characteristics of human thermoregulatory responses to cold during exercise have not been fully elucidated, we investigated the effect of low-intensity exercise on the shivering response to core cooling in cool water. Eight healthy young men (24 ± 3 yr) were cooled through cool water immersion while resting (rest trial) and during loadless pedaling on a water cycle ergometer (exercise trial). Before the cooling, body temperature was elevated by hot water immersion to clearly detect a core temperature at which shivering initiates. Throughout the cooling period, mean skin temperature remained around the water temperature (25°C) in both trials, whereas esophageal temperature (Tes) did not differ between the trials ( P > 0.05). The Tes at which oxygen uptake (V̇o2) rapidly increased, an index of the core temperature threshold for shivering, was lower during exercise than rest (36.2 ± 0.4°C vs. 36.5 ± 0.4°C, P < 0.05). The sensitivity of the shivering response, as indicated by the slope of the Tes-V̇o2 relation, did not differ between the trials (−441.3 ±177.4 ml·min−1·°C−1 vs. −411.8 ± 268.1 ml·min−1·°C−1, P > 0.05). The thermal sensation response to core cooling, assessed from the slope and intercept of the regression line relating Tes and thermal sensation, did not differ between the trials ( P > 0.05). These results suggest that the core temperature threshold for shivering is delayed during low-intensity exercise in cool water compared with rest although shivering sensitivity is unaffected.
- Subjects :
- Adult
Male
Time Factors
Physiology
030204 cardiovascular system & hematology
Thermal sensation
Young Adult
03 medical and health sciences
Oxygen Consumption
0302 clinical medicine
Physiology (medical)
Immersion
medicine
Humans
Thermosensing
Muscle, Skeletal
Exercise
Core cooling
business.industry
Shivering
Aquatic exercise
Hypothermia
Bicycling
Anesthesia
Low intensity exercise
medicine.symptom
Skin Temperature
business
030217 neurology & neurosurgery
Muscle Contraction
Subjects
Details
- ISSN :
- 15221490 and 03636119
- Volume :
- 316
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
- Accession number :
- edsair.doi.dedup.....03f28d5e778839df2ff09d825ec12beb