Human beings are diurnal creatures. We are naturally inclined to be active and stay outdoors in the daytime and sleep at night.
The body’s natural clock works on a 24-hour rhythm, called the circadian rhythm, to help humans stay awake and alert during the day and catch up on some vital rest at night. If you are experiencing difficulty sleeping with no other known cause, chances are that your circadian rhythm is going a little haywire. Worry not, there is one easy and cheap way to reset it: sunlight.
According to the CDC, the day’s light-dark cycle, caused by the sun, significantly impacts one’s sleep and alertness. The body’s master circadian clock takes light as a signal to be awake and responds to the dark as nature’s sign to get some shut-eye.
Thus, increasing exposure to sunlight (or even artificial light) during the day helps one stay alert, while darkening the bedroom at night aids better sleep.
This is because the circadian clock is most sensitive to light then. Being exposed to sunlight or very bright artificial light after waking up in the morning helps the nocturnal melatonin (sleep hormone) production to happen sooner. This can help one sleep more easily at night.
Sunlight aids in the production of serotonin, which the body converts to melatonin in the darkness. A study on benefits of sunlight published in the Environmental Health Perspectives journal said that moderately high serotonin levels result in more positive moods. Early morning exposure to sunlight can help a person have a calm yet focused mental outlook throughout the day.
The circadian clock is also highly receptive to cues offered by the light around 2 hours before the usual bedtime and through the night. Thus, dimming the lights a couple of hours before bedtime (including your light exposure from electronic devices), and ensuring that the bedroom is dark for your sleep duration is essential to good quality sleep.
Apart from regular exposure to sunlight at the right time, maintaining a consistent sleep schedule and taking your meals on time will also help maintain your circadian rhythm.