Time your nap to wake up refreshed, not groggy, based on your body's sleep cycle stages.
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Not all naps are created equal. The right nap length can leave you sharp and refreshed, the wrong one can leave you groggier than before you lay down.
Your body starts moving toward deep sleep after about 20-30 minutes. Wake up during that deep sleep phase (the 30-60 minute range) and you will likely feel sleep inertia, that disoriented, heavy grogginess. Nap for either less (staying in light sleep) or more (completing a full cycle including REM), and you sidestep that problem.
If naps are a regular part of managing tiredness, check your Sleep Debt Calculator to see the bigger picture, and our Sleep Cycle Calculator for timing your actual nighttime sleep too.
Not inherently, short, well-timed naps are a normal part of many people's routines. If you find you need a long nap daily just to function, it may be worth checking your nighttime sleep quality.
That length typically lands you in deep sleep, and waking from it causes sleep inertia, the groggy feeling. Try shortening to 20 minutes or extending to 90 to avoid that zone.
Partially, naps can reduce sleepiness and offset some sleep debt, but they do not fully replace the restorative value of consolidated nighttime sleep.