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Perceived exertion is associated with an altered brain activity during exercise with progressive hyperthermia
1Department of Human Physiology, Institute of Exercise and Sport Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark. lnnielsen@aki.ku.dk
Journal of Applied Physiology (Bethesda, Md. : 1985)
|October 20, 2001
Summary
During prolonged exercise in hot environments, perceived exertion is linked to brain activity changes, not muscle signals. Core temperature and frontal cortex EEG activity predict exertion levels, suggesting central fatigue mechanisms.
Area of Science:
- Exercise Physiology
- Neuroscience
- Environmental Health
Background:
- Heat exposure during exercise significantly impacts physiological responses.
- Understanding the drivers of perceived exertion in hyperthermic conditions is crucial for performance and safety.
Purpose of the Study:
- To investigate whether perceived exertion in heat is related to central (brain) or peripheral (muscle) physiological changes.
- To identify predictors of perceived exertion during exercise-induced hyperthermia.
Main Methods:
- 14 participants underwent submaximal exercise in normal and hot environments.
- Measurements included electroencephalogram (EEG), electromyogram (EMG), rating of perceived exertion (RPE), and core temperature.
- Statistical analysis used stepwise forward-regression to identify predictors of RPE.
Main Results:
- Perceived exertion increased significantly in the hot environment, correlating with rising core temperature.
- Electroencephalogram (EEG) activity changes, particularly over the frontal cortex, were strong predictors of perceived exertion.
- No significant correlations were found between perceived exertion and electromyogram (EMG) parameters, indicating muscle activation patterns were unaffected.
Conclusions:
- Hyperthermia-induced fatigue during prolonged exercise appears to be driven by central alterations in brain activity, not peripheral muscle fatigue.
- Core temperature and frontal EEG activity are key factors influencing perceived exertion in hot conditions.