Procognitive window 11 – Can’t get a good night’s sleep? Maybe it’s because you don’t get enough light during the day.
Higher light exposure during the day improves sleep quality
Research confirms that time spent during the day under natural sunlight or indoors under full-spectrum lighting is significantly related to subjectively perceived sleep quality. Staying outdoors or in a room with good quality full-spectrum lighting for 1-2 hours a day improves the quality of sleep at night and reduces the likelihood of sleep disturbances.
Higher light levels during the day improve mood and reduce stress
Researchers found that participants in the group exposed to bright light containing blue and cyan wavelengths indoors had higher positive affect (feelings of pleasure, joy and happiness) compared to participants in the ‘dim’ and ‘neutral‘ light groups. At the same time, participants in the ‘dimmed’ light group had significantly higher stress and depression scores.
The authors of the studies make recommendations for improving sleep quality and increasing feelings of well-being. They recommend spending 1 to 2 hours a day outdoors, ideally in the morning after waking up to support the natural circadian rhythm. For people working from home, it is essential to maximise natural daylight indoors and optimise the distribution of light in the room. In the morning and during the day, full-spectrum lighting with maximum circadian effect, or maximum melanopic EDI lux, is the solution when indoors. Evening lighting should be warm, dimmed and placed low compared to daytime lighting, and electronic displays should be turned off at least 1-2 hours before bedtime to minimise disruption to the sleep cycle.
The above is related to the secretion of the hormone serotonin being induced by good quality daylight, which affects mood, while at night the hormone is converted into melatonin, a night-time hormone. Plenty of good quality light during the day means plenty of serotonin for a good mood and melatonin for a good night’s sleep.
