Sleep Well to Be Well
1．Do you often feel tired in the morning even though you've been in bed for seven or eight hours the night before? Like many people, you are not sleeping as much as you think you are. In other words, your sleep efficiency is not that good.
2．Sleep experts define "sleep efficiency" as the percentage of time lying down that you are actually sleeping. According to explanatory journalism website vox.com, the science of sleep efficiency is still young. There is no specific number for efficiency that's been proven as linked to poor health. However, according to a New York Times report about sleep quality, some experts estimate a rough ballpark（范围）of 85 percent or above as a decent place to be.
3．Short wavelength blue light, emitted（放出）by the sun and by the screens of computers, iPads and smart phones, stops production of the sleep-inducing hormone melation（褪黑素）and makes you feel more alert. Blue light tells your brain it's daytime. Experts suggest turning off your computers and smart phones one hour or at least 30 minutes before bed.
4．Go to bed and wake up at the same time, or relatively the same time, every day. Avoid binge sleeping（狂睡）on the weekend. Consistency is key to a good night's sleep, especially when it comes to waking up. When you have a consistent wake-up time, your brain acclimates to this and moves through the sleep cycle in preparation for you to feel rested and alert at your wake-up time.
5．One of the biggest peaks in melation production happens during the 1 to 3 pm time frame, which explains why most people feel sleepy in the afternoon. If you aren't getting enough sleep at night, you've likely going to feel an overwhelming desire to sleep in the afternoon. When this happens, you're better off taking a short nap (less than 30 minutes) than resorting to caffeine or strong tea to keep you awake. A short nap will give you the rest you need to get through the rest of the afternoon, and you'll sleep much better in the evening than if you drink caffeine or take a long afternoon nap.