The impact of hyperventilation on brain alpha activity: An EEG study.

Hyperventilation (HV) is a major physiological risk factor in environments like high altitudes or hypoxic conditions, causing a range of physiological changes that can potentially impair cognitive functions. As an important bridge connecting brain physiological states and cognitive functions, the variation of alpha activity under the effect of HV has not been fully explored. To this end, this work aims to reveal the changes in EEG alpha activity induced by HV in terms of power spectrum and functional connectivity (FC). EEG data were recorded from 305 healthy young male subjects when they were under three stages: Pre-HV, HV, and Post-HV. Then, EEG power spectrum was estimated and adjusted by removing the aperiodic components. The alpha peak frequency (APF) and adjusted alpha peak frequency (aAPF) were both slowed from Pre-HV to HV and recovered in Post-HV, which revealed a U-shaped trend. Both the alpha peak power (AP) and adjusted alpha peak power (aAP) decreased during HV. FC was assessed via the weighted Phase Lag Index (wPLI), which exhibited a HV-related decrease followed by an increase in Post-HV, with a rightward lateralization shift. In summary, both the power spectrum and FC metrics showed a U-shaped tendency, suggesting a negative impact of HV on alpha activity. Our findings provide some of the first quantitative insights into the effects of HV on alpha activity, further confirming the regulatory patterns of HV on neural activity.