Timed Natural Light Exposure Found to Improve Morning Alertness

A study from Osaka Metropolitan University reveals that 20 minutes of natural light exposure before waking significantly reduces sleep inertia and enhances wakefulness.

Researchers tested three lighting conditions on 19 participants, finding that 20 minutes of natural light exposure before waking was most effective in reducing sleepiness and improving alertness.
Excessive or prolonged exposure to natural light from dawn until waking disrupted sleep quality, highlighting the importance of precise timing.
The study utilized electroencephalograms, electrocardiograms, and surveys to measure physiological and subjective outcomes under controlled conditions.
Automated solutions, such as motorized curtains, are proposed as practical, non-pharmaceutical methods to optimize natural light exposure for better sleep-wake transitions.
The findings emphasize the potential of natural light to align with circadian rhythms, offering energy-efficient and health-conscious alternatives to artificial methods like sunrise alarm clocks.