Cerebrocortical activity during self-paced exercise in temperate, hot and hypoxic conditions

Area of Science:

• Exercise Physiology
• Neuroscience
• Environmental Stressors

Background:

• Heat stress and hypoxia are known to independently impair exercise performance.
• Cerebrocortical activity is crucial for regulating cognitive functions during physical exertion.

Purpose of the Study:

• To investigate the relationship between electroencephalography (EEG) activity and self-paced exercise performance under control, hot, and hypoxic conditions.
• To examine how heat and hypoxia affect cerebrocortical activity during prolonged cycling.

Main Methods:

• Eleven well-trained cyclists performed a 750 kJ cycling time trial in three conditions: control (18°C), hot (35°C), and hypoxic (14.5% O2).
• EEG activity, including alpha (α) and beta (β) waves, was recorded from frontal and central brain regions.
• Standardized low-resolution brain electromagnetic tomography (sLORETA) was used to localize brain activity.

Main Results:

• Both alpha and beta activity decreased in the frontal and central areas during exercise in the hot condition compared to control.
• Alpha activity was lower in hypoxia compared to control, while beta activity remained similar.
• sLORETA showed alterations in somatosensory and motor cortices, with heat stress particularly affecting alpha activity in these regions.

Conclusions:

• Prolonged exercise under heat and hypoxia induces cerebrocortical alterations.
• These brain activity changes are linked to impaired attentional processing and reduced mental readiness.
• The findings highlight the neurophysiological impact of environmental stressors on exercise performance.