Dear Reader,

When you’re not getting a good night’s sleep, taking a nap during the day seems like a good way to catch up. Sometimes a nap can be just the refresher you need, improving your alertness and performance. But in other cases, napping may be interfering with your nighttime sleep, which in turn can make you want to nap even more the next day, creating a downward spiral of poor sleep.

In general, naps that last longer than 30 or 40 minutes or occur late in the day can disrupt your nighttime sleep. If you’re being treated for insomnia, your doctor or therapist may want you to avoid napping until you can get a healthy nighttime sleep schedule established.

However, if your sleep problems are limited, there are times when napping might be appropriate. For example, you might want to take a brief nap if your sleep schedule was disrupted by a one-time event or if you expect to go without sleep for an extended period of time, such as an upcoming work shift. Some people enjoy napping so much that they make it a planned part of their sleep routine.

If you’re going to nap, do it in a quiet, cool, dark place with few distractions so that you can actually sleep rather than toss and turn. It is generally agreed that a nap of roughly 20 minutes is optimal. That’ll get you into stage 2 light sleep. Longer naps allow one to slide into stage 3 deep sleep, which, yes, is a very physiologically restorative sleep, but if you wake up suddenly in the middle of it, you will feel groggy afterward. The best time for a nap is typically after lunchtime or in the early afternoon, which is when most people tend to feel sleepiest. Take your usual bedtime into account, as well. Naps should generally occur at least four to five hours before your bedtime. Short naps taken during this time are less likely to interfere with nighttime sleep.