Do you ever go to bed and, as tired as you are, you just feel too alert? Or you find it really difficult to keep to a set bedtime? The problem could well be that your circadian rhythm is out of alignment with the natural solar day. And if it is, I have a really simple sleep tip for you: get outside early!
Normally when people have trouble sleeping they focus on what they do just before bed, and forget about what they did in the early morning. It seems to make sense, what happens close to getting into bed must be most important for determining what kind of night you are going to have. And while it’s true that there is a lot you can do right before bed for better sleep, ca n what you do the other end of the day really make a difference?
The answer: yes, yes it can. Among the many things that your circadian rhythm influences is the time you start to feel sleepy at night, but since it is not completely set it can sometimes get out of whack and cause disruptions to your sleep, but the good thing is that that means it can be fixed too. Exposure to a very bright light, like direct sunlight, can actually help with your circadian rhythm in two distinct ways.
So that your circadian rhythm can adjust for the seasons and correct itself it is sensitive to light. Exposure to daylight, especially early in the morning, helps to synchronize your circadian rhythm to the solar day. The more your repeat this, the more deeply entrained your circadian rhythm becomes, and the less vulnerable it becomes to disruption.
This sensitivity to light does of course mean that too much bright light at the end of the day will cause a disruption in the rhythm and lower your sleep quality. However, when you are exposed to very bright light, such as direct sunlight, throughout the day it actually makes your circadian photoreceptors less sensitive to light at night time. This means that if you spend a lot of time outside each day, you can use your phone in the evening without as much of the normally associated melatonin suppression, and therefore still sleep well.
What to do
Normal indoor light is too dim to offer these protections, so if you work inside all day you will still be vulnerable to circadian disruption. This makes regular exposure to direct sunlight more important; some easy ways to increase your exposure are to:
- Eat breakfast in a room with a south facing window
- Sit outside when you take your lunch break
- Find an outdoors hobby
- Spend time at the park on your days off
- Get up earlier so you can go for a morning walk (this one is easier later when the others have already improved your sleep)
Your circadian rhythm is an important biological function that regulates the timing of many of your body’s processes, including sleep. Regular exposure to day light helps to synchronize it and make it less vulnerable to disruption. This means that spending some time outside each day, especially in the early morning if possible, is a great way to get a good night’s sleep. A good night really does start in the morning.
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Effect of Light on Human Circadian Physiology
Jeanne F. Duffy, M.B.A., Ph.D.a,* and Charles A. Czeisler, Ph.D., M.D.b,c