Sleep Efficiency is the percentage of total time in bed that is spent sleeping. For example, spending 8 hours in bed and 6 of those hours asleep yields a sleep efficiency of 75%. With a sleep efficiency of 85% or higher, you are doing well.
If you use the Automatic Sleep Recording feature, your sleep efficiency does not factor in the amount of time you took to fall asleep, because reading a book or watching TV in bed one night can look the very similar to having a difficult time falling asleep another night. With auto sleep, the sleep efficiency value is primarily a reflection of the amount of time during the night you spend awake.
If you prefer a sleep efficiency value that includes the time you spent falling asleep, you may want to start your sleep recordings manually. Alternatively, if you prefer using the Automatic Sleep Recording feature, you can manually edit your bedtime after the recording is complete.
Improving your sleep efficiency
Maintaining a consistent sleep schedule is a key ingredient to maximizing sleep efficiency. In addition, try to avoid bright light and stimulants like caffeine or alcohol at night, aim to eat your last meal two to three hours before bedtime, so you don’t go to sleep either too full or too hungry, and consider adding exercise to your daily routine. Other good ideas include limiting your fluid intake before bedtime to minimize trips to the bathroom during the night, and creating a dark, cool, quiet (use white noise if needed) environment conducive to falling asleep and staying asleep until you wake up naturally.
Certain factors that can impact your total sleep may be out of your control. For example, various sources of stress, children, or your work schedule may play a role. To offset these, try winding down your day 1–2 hours before bedtime with a relaxing activity like reading, listening to music, or relaxation exercises. Your bedroom should be visually pleasing and very comfortable, so you look forward to going to bed.
Finally, if you wake up at night, don’t stress. Waking up one or two times per night is very normal, and in fact segmented sleep was the norm until the invention of artificial lighting in the 19th century. If you don’t fall back asleep within about 20 minutes of waking up, you may want to try getting up and engaging in a relaxing activity until you feel sleepy again.
Learn more:
http://nymag.com/scienceofus/2017/03/sleeping-through-the-night-is-a-relatively-new-invention.html