Did you get up this morning feeling somewhat-rested or not rested at all? Are you ordering that third cup of coffee mid-morning to keep your eyes open? Are you having trouble concentrating by early afternoon? These signs might suggest that you did not have a good night's sleep. Light seeping into your sleeping environment may be a factor in preventing restful sleep.
You may have heard that humans have an internal clock that runs on an approximately 24-hour cycle described as circadian rhythm? This clock regulates sleeping and eating patterns, core body temperature and many other biologic functions. A tiny portion of the brain called the suprachiasmatic nucleus–located in the hypothalamus–controls this clock, in part, by stimulating the secretion of Melatonin from the pineal gland.
Melatonin, often called the "sleep hormone", is released when cells in our retinas observe darkness as the sun is setting. Melatonin levels rise in the early evening, peak around 3AM and then decrease to a low by 7:30AM. While morning light stimulates us and gets us going, exposure to light in the evening may depress the production of melatonin and make it harder to fall asleep. Think of the hormone as a messenger letting the brain know that it is time to physiologically wind down. Melatonin is not a sleeping pill.
According to the National Sleep Foundation, adults need between 7-9 hours of sleep depending upon age, and darkness is essential for sleep. "How dark?" you might ask. According to Dr. Chris Winter, you "shouldn't be able to see your hand in front of your face."
Since we spend 30% of our life in bed, it is essential that we become cognizant of our pre-bed routine and create a sleeping environment that will allow us to get a restful night sleep.
Smart phones, computers and e-readers can emit high concentrations of blue light that is detrimental to sleep. It is recommended that you limit exposure to such screens one hour before hitting the sack. During the hour before bedtime, consider lowering the ambient light in your home with the use of dimmers.
In the bedroom, make certain that all windows are curtained and don't allow in any light. It may be necessary to consider black-out curtains. If there are nightlights, put them in the hallway and use red bulbs. Make certain light is not leaking into the room from closed doors. Lastly, consider an eye-mask if you can not block out the ambient light. While effective, it may take some time to get used to.
It is important to have consistency in your routine–going to bed around the same time each night and rising 8 hours later. In the morning, if you awaken when it is dark, you may want to turn on the lights to let your circadian clock know that you are starting your day.
Your environment is only one of many factors that may affect your sleep. With the advent of personal 24-hour tracking devices it is now possible to obtain data about your own sleeping pattern. Utilizing your own data will allow you to gain insights into the factors that might improve your overall health.