Taking a nap in the morning won't make you more tired


Researchers have long wondered whether napping after an alarm goes off in the morning affects wakefulness and sleep quality.

Tina Sundelin's team at Stockholm University in Sweden invited 31 participants who dozed at least twice a week in the morning and had them spend two nights in the sleep lab.

On the first night, participants can go to bed on time as usual, set the alarm clock at the normal wake-up time, and wake up on time.

About a week later, the participants returned to the lab again for testing. They set an alarm half an hour before they should wake up, press the "Remind Later" button every 9 to 10 minutes, and sleep a little longer.

Upon waking up, participants were immediately subjected to a saliva test that measured the levels of the hormone cortisol in their bodies. The higher the cortisol level, the more awake the participant was. Participants also rated their level of sleepiness on a scale of 1 to 9, and tested cognitive ability and emotional status at the time of waking up and 40 minutes after waking up.

The researchers found that participants who dozed in the morning had slightly higher cortisol levels, but there was no difference between the two participants in terms of lethargy, mood, or cognitive ability.

Overall, participants who dozed in the morning slept an average of 6 minutes less. And in the last half hour of sleep, their brain waves showed signs of poor sleep quality. But overall, there was no substantial difference in sleep quality between the two nights. Taking a nap in the morning does not make people sleepier, less emotional, or less cognitively aware during the day than waking up directly.

Jeffrey Durmer, a staff member at SleepImage, a sleep-monitoring device company, said the study's participants were people who regularly nap in the morning, so the findings may not apply to people who take occasional morning naps.

In addition, the researchers asked nearly 1,500 people to complete a questionnaire on their sleep habits, and 69 percent of those respondents said they occasionally take a nap in the morning, especially on weekdays. In addition, morning nappers were more likely to be women, with an average age of 6 years younger than non-nappers, and four times more likely to call themselves "night owls."