Yawning occurs to increase oxygen intake before sleep.
NOT BSTOTAL BS
TOTAL BS — Verdict: False
Verified by Lenz ·
The Short Version
This claim is false. The idea that yawning exists to increase oxygen intake has been largely abandoned by the scientific community. Controlled experiments show that changing oxygen or CO₂ levels does not affect yawning frequency. While yawning does involve a deep breath, this is not its purpose. Current research points instead to brain cooling, sleep-wake state transitions, and arousal regulation as the primary functions of yawning. The "before sleep" framing adds an additional unsupported specificity.
Caveats
The oxygen-intake theory of yawning has been experimentally discredited — altering oxygen and CO₂ levels does not reliably change yawning rates.
The few sources appearing to support this claim use heavily speculative language ('may,' 'could theoretically') and describe possible side effects of yawning, not its biological purpose.
Current scientific consensus favors brain-cooling and sleep-wake transition mechanisms over respiratory explanations for yawning.