That beloved button on top of your alarm clock may not be so helpful after all. Spending the last half hour or so of nighttime rest in what researchers call “fragmented sleep” has consequencesTrusted Source for your ability to function throughout the day. Pro-tip: Try the 90-minute sleep cycle hack by setting two alarms — one for 90 minutes before you want to wake up and one for when you actually want to wake up. The theory is that the 90 minutes of sleep you get between snoozes will be a full sleep cycle, allowing you to wake up after your REM state, instead of during.
