Five minutes left: snooze button popular in Germany

Boston. Press once and sleep for another five minutes. The snooze button on an alarm clock is tempting, especially early in the morning. While sleep specialists advise against it, a study shows that this practice is widespread – especially in Germany. A team led by sleep medicine specialist Rebecca Robbins of Harvard Medical School reported in the journal "Scientific Reports."

The team analyzed data from more than 21,000 users of the "Sleep Cycle" app worldwide, covering a total of approximately three million nights. According to the data, these people used the snooze function on almost 56 percent of nights. Almost half of them even pressed the button on more than 80 percent of days. This group snoozed for an average of about 20 minutes on these days. Among all app users, the average was 11 minutes per day.

When people pressed the button in a morning, they usually did so more than once: In Sweden, people pressed it an average of 2.7 times on such days. In Germany and the USA, the average was 2.5 times each, the team further reports.

This occurred least frequently in Japan and Australia – but even there, it was still used 2.2 times per day. And women access it slightly more often than men – an average of 2.5 times compared to 2.3 times. Unsurprisingly, the function was used primarily on weekdays and less frequently on weekends.

What's striking, however, is that those who slept a maximum of five hours were more likely to ignore the snooze button. The researchers' explanation: This group, in particular, who have a particularly limited amount of sleep, is particularly careful to make the most of it – right up to the last minute. There's simply no time to snooze any longer.

"Unfortunately, the snooze button disrupts some of the most important stages of sleep," Robbins explained. "The hours just before waking are rich in REM sleep. Pressing the snooze button interrupts these crucial sleep stages and then usually provides only light sleep between snooze alarms." The study also found that sleepers tend to press the snooze button repeatedly—on average, 2.4 times.

In contrast, Robbins' researchers recommend uninterrupted bed rest: For the best possible sleep, one should set the alarm clock for the latest possible time "and then get out of bed when the first alarm sounds."

Experts generally recommend seven to nine hours of sleep per night. Sleep deprivation can, among other things, negatively impact the psyche, increase the risk of cardiovascular disease, and impair mental performance.

RND/dpa