The study published in the Journal of Affective Disorders included more than 400,000 participants from the UK biobank program. It was found that a lack of daytime light exposure was a risk factor for poor mood, insomnia, and depressive symptoms.
Researchers noted that most messaging around health and light is focused on avoiding light at night. Previous research has found that light during nighttime can disrupt the body clock, also known as circadian rhythm. This study helps to highlight the importance of getting enough daylight to ensure the body can function optimally.
Circadian Rhythm
Circadian rhythm is a natural internal process that regulates the sleep-wake cycle. It repeats roughly every 24 hours and can help guide the body to let it know when to sleep and when to be awake. It’s vital in helping to regain energy lost from being awake and performing daily activities.
Co-author of this study said, “In this study, we observed that the greater time spent in outdoor light during the day was associated with fewer depressive symptoms, lower odds of using antidepressant medication, better sleep, and fewer symptoms of insomnia.”
The reduction of these symptoms may be explained by the effect of light on circadian rhythm and the direct impact that sunlight creates on mood centers in the brain.
People tend to spend most waking hours in artificial lighting conditions and relatively bright nighttime light exposure. By making minor adjustments to a daily routine, some may improve their sleep, mood, and energy levels.
Researchers concluded the study by citing that insufficient exposure to daytime light could be a critical factor that contributes to poor sleep outcomes and depressive disorders. They suggest simple advice for everyone; when the sun is out, get as much light as you can, but after it sets, keep it dark.
This study helps to show the importance of daytime light. Researchers recommend exposure to bright lights first thing in the morning and spending time outdoors, getting enough sunlight during daytime hours. Exposure to blue light should be avoided, and bright lights at night should be turned off, screen time-limited, and lights in the bedroom blocked off.
By correcting your circadian rhythm, you will feel more awake during the day and sleepy at night. As this study also suggests, you can help boost mood and reduce episodes of insomnia.