Naps longer than 30 minutes can backfire, doctor explains how

A short daytime nap is often seen as a quick fix for fatigue, helping people feel refreshed and more alert.

However, sleep specialists warn that extending a nap beyond a certain duration can have the opposite effect, leaving individuals more tired, disoriented and even disrupting their night-time sleep cycle.

According to Dr Tushar Tayal, Associate Director - Internal Medicine, CK Birla Hospital, Gurugram, the timing and length of a nap play a crucial role in how the brain responds on waking.

"A quick power nap may help you become more focused and energised. Nonetheless, the moment your nap becomes longer than half an hour, your body starts to transition to a different phase of sleep, and here lies the problem," he explains.

Sleep cycles and why timing matters

Sleep is not a uniform state but a sequence of stages that gradually shift from light sleep to deeper phases. According to Dr Tayal, this natural progression is the key reason why longer naps can feel counterproductive.

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"Sleep happens in phases, gradually transitioning from light sleep to increasingly deeper ones. In the initial half an hour, your body usually remains in a lighter phase, allowing you to feel well-rested when you wake up," he says.

However, once the body crosses this threshold, it enters deeper sleep stages, which are harder to interrupt without side effects.

"After this period, the brain usually enters deep sleep, which, if interrupted by a sudden awakening, leaves you in a sleepy, sluggish, and disoriented condition, commonly known as sleep inertia, which lasts from several minutes to even over an hour, defeating the main purpose of taking a nap."

What is sleep inertia?

Sleep inertia refers to the groggy, confused and slowed-down feeling that occurs immediately after waking from deep sleep. Instead of feeling refreshed, individuals may experience reduced alertness, poor concentration and difficulty resuming tasks.

This is why a nap that seems “long enough to be restful” can sometimes make people feel worse than before they slept.

Can long naps affect night-time sleep?

Beyond short-term grogginess, excessive daytime napping can also influence the body’s natural sleep-wake cycle.

Dr Tayal warns that longer naps may interfere with night-time rest by reducing the body’s natural sleep drive.

"Naps that last too long can affect night-time sleep as well, since they suppress the urge for sleep, making you unable to sleep at regular hours," he explains.

This disruption can lead to difficulty falling asleep at night, fragmented sleep or a delayed sleep schedule over time.

The ideal nap duration for best results

While naps can be beneficial, timing them correctly is essential for maximising their benefits without side effects.

Dr Tayal recommends keeping naps short and controlled.

"In general, most individuals should take shorter naps from ten to twenty minutes, which will make you feel truly energised without having the effect of sleep inertia," he advises.

Short naps help the body remain in lighter sleep stages, allowing a smoother and more refreshing wake-up experience.