Light exposure during sleep impairs cardiometabolic function

This study explored the effects of light exposure during sleep on cardiometabolic health. Twenty healthy adults were exposed to dim light or room light (100 lux) over two nights. sleeping under room light increased heart rate and reduced heart rate variability, indicating elevated sympathetic nervous system activity. Participants exposed to light showed higher insulin resistance the following morning compared to those in dim light. These findings suggest that even moderate light exposure during sleep disrupts cardiometabolic regulation, potentially contributing to health issues like diabetes and metabolic syndrome.

To improve cardiometabolic health, avoid exposure to artificial light during sleep. Use blackout curtains and eliminate light-emitting devices in the bedroom. This advice is based on controlled experimental evidence showing light-induced disruptions in insulin sensitivity and autonomic regulation. Small lifestyle changes, such as dimming lights before bed, can support better sleep and metabolic outcomes.