Jeramey Lende/ShutterstockMornings are rough, but hitting snooze can make that ungodly hour seem just a little more bearable (and could be a sign of intelligence). At the push of a button, you give yourself permission to stay snuggled under the covers for another blissful nine minutes (or 18 or 27, if we’re being honest). But wait—why do snooze buttons automatically set for that long instead of an even ten?
Your iPhone’s automatic settings actually got there start half a century ago. Alarm clocks were introduced to snooze buttons in 1956 with General Electric-Telechron’s Snooz-Alarm, according to Pacific Standard. That model’s snooze lasted nine minutes, but there are a few theories as to why.
Alarm clocks did exist before the snooze function, so there was already a standard gear setup that innovators had to work with. Getting the gear teeth to line up to allow for exactly ten minutes wasn’t possible, so they had to choose between nine minutes and a few seconds or a little bit over ten minutes.
Here’s where the theories start to differ. Some people say reports in the 1950s suggested ten minutes was enough for drowsy people to fall back into deep sleep. That would mean they’d wake up cranky again, so nine minutes was the sweet spot between more time in bed without letting it get out of hand. (Find out which alarm clock will help you get up without hitting snooze.)
Others believe that single minute would let people get the most out of their day. That extra minute won’t make much difference when you’re dozing, but it could make a difference in how much time you have to get ready. (Learn why you seem to always wake up right before your alarm goes off.)
But the most common theory seems to come down to simplicity. A double-digit snooze would be harder to program than a single-digit one, so designers figured the less complicated design was the way to go.
Later clocks didn’t necessarily follow Snooz-Alarm’s lead (Westclox’s Drowse clock let snoozers choose between five and ten minutes), but other clocks—including iPhone’s alarm app—decided to pay homage to the original nine minutes.
No matter what the original reasoning, those people who say ten minutes is too much sleep might have been onto something—though same goes for nine minutes. Trying to squeeze in just a few minutes more shut-eye after you’ve already woken up messes with your body’s inner sleep clock. “First, you’re fragmenting what little extra sleep you’re getting so it is of poor quality,” sleep medicine specialist Robert Rosenberg, DO, FCCP, tells CNN. “Second, you’re starting to put yourself through a new sleep cycle that you aren’t giving yourself enough time to finish. This can result in persistent grogginess throughout the day.” You’d be better off just admitting you always hit snooze three times in the morning, and setting your alarm half an hour later. Or 27 minutes, as your weirdly specific alarm clock would do.