You don't lose if you snooze

It's common to want to stay in bed, potentially even go back to sleep, when the alarm goes off in the morning. The snooze button has been a function in alarm clocks and cell phones for decades and is often claimed to have negative effects, both on sleep and the brain's ability to wake up. However, there has been no scientific research to support these claims. Researchers from Stockholm University have now investigated how common snoozing is and what effects this behaviour has on sleep, sleepiness, mood and cognitive abilities.

- 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. But there were no negative effects of snoozing on cortisol release, morning tiredness, mood, or sleep quality throughout the night, says Tina Sundelin, researcher at Stockholm University and lead author of the paper.

In the first study, 1732 individuals answered questions about their morning habits, including how often they use the snooze button. Many reported snoozing regularly. This behaviour is especially common among young adults and evening people. The most common reason for snoozing is feeling too tired to get out of bed when the alarm goes off.

In the second study, 31 regular snoozers spent two nights in a sleep lab in order to measure their sleep in more detail. One of the mornings they were allowed to snooze for 30 minutes and the other they had to get up right when the alarm went off. The results are calming for those who snooze. Even though participants' sleep was disturbed during the half hour of snoozing, most of them still got quite a lot of it -- more than 20 minutes. This means that their total night's sleep was barely affected. Furthermore, in the snooze condition no one had to wake up from deep sleep, and the snoozers performed a bit better on cognitive tests right upon waking. Meanwhile, there were no clear effects of snoozing on mood, sleepiness, or the amount of cortisol in the 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. 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.

- It's of course important to remember that the study only included people who are regular snoozers and find it easy to go back to sleep after each alarm. Snoozing is most likely not for everyone, says Tina Sundelin.