Scientists found that people who napped for 30 to 90 minutes had better word recall – which is a sign of good memory – than people who did not nap or who napped for longer than 90 minutes. People who napped for that golden 30 to 90 minutes were also better at figure drawing, another sign of good cognition.
One theory explaining poor cognition in those who take longer naps: Resting more during the day may be a sign of poor quality nighttime sleep, according to Gamaldo. “In the study, naps longer than 90 minutes could have been called ‘a second sleep.’” This poor quality nighttime sleep – the kind that requires extra-long napping during the day – can lead to cognitive problems, she adds.
Longer nap problems
Longer naps can pose a couple of other problems, says Gamaldo, including:
- Temporary grogginess: People who take longer naps may feel groggy immediately after they wake up, says Gamaldo. “Because they are sleeping longer, they may wake up from a deeper stage of sleep, which occurs later in the cycle, and feel fuzzy headed,” she says.
- Inability to sleep at night: Gamaldo has seen patients who take long naps during the day have insomnia at night. “You might want to think about limiting your napping if you’re having problems with insomnia, or it’s taking you more than 30 minutes to fall asleep at bedtime.”
Overall, studies show that people who sleep too much or too little may have poor health and even a shorter life span. Consequently, “people need to get the right quantity and quality of rest,” says Gamaldo.