Just five more minutes — it's the plea of many people once their alarm goes off. So they hit the snooze button.
Many believe this practice is a bad thing, but there isn't any scientific proof that it's harmful. So researchers from the Department of Psychology at Stockholm University decided to do their own study.
What they found, however, was just the opposite of the assumptions.
"Our findings show that those who snooze on average sleep slightly shorter and feel more drowsy in the morning compared to those who never snooze," Tina Sundelin, researcher at Stockholm University and lead author of the paper, said in a university press release. "But there were no negative effects of snoozing on cortisol release, morning tiredness, mood or sleep quality throughout the night."
The researchers conducted two studies. In the first, 1,732 people answered questions about their snooze habits, with many saying they do so regularly. The common reason was feeling too tired to get up when the alarm went off.
In the second, 31 people who regularly snoozed spent two nights in a sleep lab. On one morning, they could snooze for half an hour, but the other they had to get up as soon as the alarm went off.
The researchers found that on the snooze morning, most participants went back to sleep for 20 minutes or more. Because they eventually awoke from a lighter sleep, they performed better on cognitive tests taken first thing. The researchers also found no effect on mood, sleepiness or the amount of cortisol in the snoozers' saliva.
"Our study shows that half an hour of snoozing does not have negative effects on night sleep or sleep inertia, the feeling of not quite being alert in the morning," Sundelin said.
"If anything, we saw some positive outcomes, such as a decreased likelihood of waking from deep sleep. When participants were allowed to snooze, they were also a bit more quick-thinking right when they got up."
Sundelin did note the study included only people who regularly hit snooze and were used to going back to sleep quickly.
