Heat exposure does not alter eccentric exercise-induced increases in mitochondrial calcium and respiratory
Ben Rattray1, C Caillaud, P A Ruell
1Exercise, Health and Performance Research Group, Faculty of Health Science, University of Sydney, Sydney, Australia. ben.rattray@canberra.edu.au
European Journal of Applied Physiology
|March 19, 2011
Summary
Intermittent heat exposure did not protect mitochondria from eccentric exercise damage. Eccentric exercise impaired mitochondrial calcium and respiration, with no benefit from heat acclimation.
Area of Science:
- Exercise Physiology
- Mitochondrial Biology
- Heat Stress Research
Background:
- Eccentric exercise causes muscle damage, altering mitochondrial calcium content (MCC) and respiratory function.
- Heat acclimation offers cross-tolerance to various stresses, but its mitochondrial protective effects against eccentric exercise are unknown.
Purpose of the Study:
- To investigate if intermittent heat exposure protects mitochondria from eccentric exercise-induced damage.
- To assess the impact of heat exposure on mitochondrial calcium handling and respiratory function post-eccentric exercise.
Main Methods:
- Rats underwent 3 weeks of intermittent heat exposure (36°C) or cool conditions.
- Animals performed decline treadmill exercise; mitochondrial calcium content, respiration, and mPTP opening were measured.
- Measurements were taken immediately, 2h, and 48h post-exercise.
Main Results:
- Heat exposure showed lower plasma creatine kinase, suggesting reduced muscle damage.
- Eccentric exercise significantly increased MCC and reduced mitochondrial respiratory control ratio 48h post-exercise.
- Heat exposure did not alter MCC levels or mitochondrial function following eccentric exercise.
Conclusions:
- Intermittent heat exposure does not protect against mitochondrial dysfunction caused by eccentric exercise.
- Eccentric exercise impairs mitochondrial respiration and calcium loading, with effects most pronounced 48h post-exercise.
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