Effects of red light on sleep and mood in healthy subjects and individuals with insomnia disorder

This randomized study examined the effects of red light on sleep and mood in both healthy participants and individuals with insomnia. Red light exposure one hour before bedtime improved subjective alertness but also increased negative emotions and anxiety, especially in individuals with insomnia. While red light shortened sleep onset latency, it fragmented REM sleep and lowered overall sleep efficiency. These findings suggest red light may not be ideal for sleep, as its emotional and physiological impacts can disrupt restorative processes crucial for cognitive and emotional health.

Avoid using red light before bedtime to minimize sleep disruption and negative emotional effects. Instead, opt for dim, warm lighting to promote relaxation and enhance sleep quality. This recommendation is based on evidence showing that red light increases anxiety and fragments REM sleep, particularly for individuals with insomnia. Personal responses may vary, so prioritize lighting that aligns with your sleep needs and emotional state.