AlterMe doesn't currently track naps — your sleep score and metrics reflect your nighttime sleep only. But how you nap during the day can directly affect the data you do see, so it's worth understanding how to do it well.
How naps affect your nighttime sleep
Sleep pressure — your body's drive to sleep — builds throughout the day. Napping releases some of that pressure, which can make it harder to fall asleep at night, reduce deep sleep, and shorten overall sleep duration. Whether that's a problem depends largely on when and how long you nap.
Napping well: the basics
Time it early — aim to nap before 3pm. Later naps eat into your nighttime sleep pressure and make Wind Down harder
Keep it short — a 10–20 minute nap restores alertness without entering deep sleep, meaning you wake up feeling refreshed rather than groggy. Naps over 30 minutes can cause sleep inertia and are more likely to disrupt your night
90 minutes is the exception — a full sleep cycle nap can be restorative, but should be treated like a sleep session and timed accordingly. Best suited for shift workers or those with genuinely irregular schedules
If you nap regularly
Keep an eye on your nighttime Wind Down time, deep sleep, and overall sleep duration on days you nap versus days you don't. That comparison will tell you more about your personal response to napping than any general guideline.