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Supramaximal Intensity Hypoxic Exercise and Vascular Function Assessment in Mice
Published on: March 15, 2019
Exercise delays the hypoxic thermal response in rats.
A D Ray1, A J Roberts, S D Lee
1Department of Exercise and Nutrition Science, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|March 11, 2003
Summary
Exercise during hypoxia delays the body's temperature drop but increases tissue damage in the brain and lungs. This suggests exercise worsens acute mountain sickness by counteracting protective responses.
Area of Science:
- Physiology
- Environmental Medicine
- Exercise Science
Background:
- Hypoxia, or low oxygen, can decrease body temperature (hypoxic thermal response, HTR) in mammals, potentially protecting against tissue damage.
- Exercise is known to exacerbate acute mountain sickness, but its interaction with the HTR is not fully understood.
Purpose of the Study:
- To investigate whether exercise counteracts the hypoxic thermal response (HTR) and its effect on hypoxic tissue damage.
- To determine the impact of exercise on body temperature regulation during acute hypoxia.
Main Methods:
- Rats were subjected to either normoxia or hypoxia (10% O2) for 24 hours, with some groups exercising and others sedentary.
- Body temperature was monitored via telemetry throughout the experiment.
- Histopathological analysis of brain and lung tissues was performed to assess damage and water content.
Main Results:
- Exercising normoxic rats showed increased body temperature, while sedentary hypoxic rats exhibited a decreased body temperature.
- Exercising hypoxic rats maintained their body temperature during the initial exercise period but reached a similar low point as sedentary hypoxic rats later.
- Exercising hypoxic rats experienced significantly greater brain and lung damage and edema compared to sedentary hypoxic and normoxic rats.
Conclusions:
- Exercise early in hypoxia delays the onset of the hypoxic thermal response (HTR) but does not prevent it.
- Counteracting the HTR through exercise exacerbates brain and lung damage and edema in hypoxic conditions, even without ischemia.
