Things You Should Know
As long as your alarm is set for the proper time and date, it will go off in Do Not Disturb, silent, and even airplane mode. Do Not Disturb, Sleep, and other Focus modes will only silence your other notifications, including phone calls, text messages, and app alerts.
Bedtime mode, like Do Not Disturb, has no effect on the morning alarm. The alarm on your watch will continue to ring, but all other notifications will be muted.
Quickly turn your Sleep Focus on or off
Open Control Center, then tap Sleep. Your Sleep Focus turns on or off again at your next scheduled bedtime or wake up time.
Sleep Mode is designed to activate automatically based on a schedule you set up in the Health app on your iPhone.
Check the iPhone Alarm Volume
The first thing to check when your iPhone alarm is not going off is the volume on your iPhone. This is because the alarm volume matches the overall volume set for your iPhone. To check this: Open the Control Center, then swipe up on the volume slider to raise the volume on your iPhone.
Sleep Mode is silence on phone calls on top of DND. The Do Not Disturb mode disables certain apps and activities on the phone.
For the sleep schedules you set, a Sleep Focus helps reduce distractions before and during bedtime. For example, it can filter out notifications and phone calls, and it can signal to others that you're not available. You can also schedule a wind down period to begin from 15 minutes to 3 hours before your bedtime.
Apple's sleep mode, called Sleep Focus, allows you to set a sleep schedule free from iPhone notification distractions. Sleep Focus enables iPhone users to turn off notifications when they want to relax and signal to others that they are unavailable.
Do Not Disturb is a mode on smartphones and tablets that silences most, if not all, incoming notifications. This can include phone calls, text messages, and app notifications. The action that would generate a notification still occurs, but the notification will be silenced and won't activate the device's display.
If you can, try putting your phone on “do not disturb” mode or silent when you go to bed. Because even though you may not be on it, the text alerts, game notifications or email buzzes can interrupt your deep sleep.
Even when DND mode is enabled, you continue to receive calls, text messages, and other notifications on your phone. The only difference is that your phone will not ring or vibrate in response to those calls and notifications. You'll see all those missed calls, text messages, and notifications when you use your phone.
Power surges or power drops occurring when a machine is powered by its power adapter are more harmful to a sleeping computer than to one completely shut down. The heat produced by a sleeping machine exposes all components to higher heat more of the time. Computers left on all the time may have a shorter life.
Some studies have found that deep sleepers can block out noise entirely during non-rapid eye movement sleep, which can happen 3-4 times a night. If you've become a heavy sleeper and your alarm sounds during one of these cycles, this could be the reason why you don't hear it anymore.
In the default behavior, the DND setting turns off calls and notifications, but it keeps any set alarms active so you can wake up on time. Androids allow for more customization than iOS.
My iPhone's alarm is limited to 15 minutes before it turns itself off. (If I know it's going to be a short night I set it out of my reach, so for the times I've been too exhausted to get up and hit the snooze or turn it off, it has gone on for a full 15 minutes before stopping.)
It's handy if you're in the cinema, at a meeting, about to go to sleep, or for any other reason don't want to be disturbed.
Since negative thoughts are often cognitively arousing, fixating on them can make insomnia worse. It's interesting to note that: in one study, subjects who were asked to focus on their regrets at bedtime took longer to get to sleep than those that did not.