If you’re not a morning person — or even if you are — it can feel good to stay snuggled under the covers for just a little longer after you first wake up. That’s why it’s so easy and tempting to just slap — or in the case of smartphones, swipe — the snooze button. Your alarm shuts off and silence prevails again, allowing you to catch a few more Zs before your alarm wakes you up again in 9 minutes. So, why is the snooze time 9 minutes instead of an even 10? Alarm clocks were introduced to snooze buttons in 1956 with General Electric’s Snooz-Alarm. It turns out that when designers added the snooze feature, getting the gear teeth to line up to allow for exactly 10 minutes wasn’t possible. They had to choose between setting it at 9 minutes or a few seconds over 10 minutes. A double-digit snooze would have been harder to program than a single-digit one, so the less complicated design was the way to go. It was also a bit more beneficial for the snoozers. In terms of sleep, 9 minutes is just enough time for a brief rest. Once you get past the 10-minute mark, your body can start to fall back into a deep sleep, which would make waking up again even more unpleasant. You might be wondering if snoozing your alarm is good for you. Unfortunately, the consensus among sleep experts is that using snooze isn’t all that good for you. Trying to squeeze in a few more minutes of shut-eye once you’ve already awakened messes with your body’s inner sleep clock, making you feel fatigued for the rest of the day. Waking up repeatedly can also cause strain on the nervous and cardiovascular systems. So, snooze should be something you do only once in a while, not every day.
