Sleep Efficiency

Sleep efficiency is the percentage of your time in bed that you spent asleep. Eight hours in bed with seven hours of sleep is 87.5 percent.

It is useful because it separates two things that are easy to confuse: how much time you gave to sleep and how much sleep you got. Someone who is in bed for nine hours and sleeps six has a very different problem from someone who is in bed for six hours and sleeps six, and the total sleep figure alone cannot tell them apart.

Eighty-five percent or above is the figure usually quoted as healthy for an adult. Consistently below that, especially with long stretches awake in the night, is the pattern that sleep clinicians look at first. Consistently above ninety-five can mean the opposite problem, that you are not spending enough time in bed and are falling asleep the instant you lie down.

What it is not

It is not sleep quality. Efficiency counts minutes and knows nothing about how much deep or REM sleep you got, so a shallow unbroken night scores higher than a restorative night with one trip to the bathroom.

Where you see it in FitnessSyncer

Sleep efficiency is worked out for every night that arrives from a connected tracker and appears in the built-in Sleep report, on your Dashboard and with the rest of your sleep data. Our sleep efficiency calculator works one out from a single night.