What bedtime do you need?
The US National Heart, Lung, and Blood Institute gives 7 to 8 hours of sleep a day for adults. Count back from your wake time, and add the time that you need to fall asleep.
| Wake time | Asleep by, for 8 hours | Asleep by, for 7 hours |
|---|---|---|
| 5:00 am | 9:00 pm | 10:00 pm |
| 5:30 am | 9:30 pm | 10:30 pm |
| 6:00 am | 10:00 pm | 11:00 pm |
| 6:30 am | 10:30 pm | 11:30 pm |
How do you move your sleep earlier?
These habits are from the healthy sleep guidance of the institute:
- Go to bed and wake up at the same time each day. Keep the difference between weeknights and weekends to about one hour or less.
- Use the hour before bed for quiet time. Avoid bright artificial light, such as a TV or a computer screen.
- Stop caffeine early. Its effects can last up to 8 hours.
- Avoid alcohol and large meals before bed.
- Spend time outside each day and be physically active.
- Keep your bedroom quiet, cool and dark.
Move your bedtime in small steps if a large change does not work. You cannot fall asleep two hours earlier on the first night.
What do you do in the morning?
| Step | What the research found |
|---|---|
| Expect 15 to 30 minutes of grogginess | Many studies show a return to normal performance in that time (Hilditch and McHill 2019) |
| Move for 5 minutes | Faster reaction times at 5 and 15 minutes in one small 2026 trial (Beauchamps and colleagues) |
| Turn on the lights | Light after waking has a limited effect (Hilditch and McHill 2019) |
| Do not snooze for a long time | 30 minutes of snoozing cost about 6 minutes of sleep in a 2024 laboratory study |
The 2019 review states that no method that you apply after waking has clear proof. Sleep is the reliable part. See what sleep inertia is and how long it lasts.
Why do you feel tired when you wake up early?
There are three common causes:
- Too little sleep. The alarm moved, and the bedtime did not.
- Your body clock. The 2019 review found that sleep inertia is greatest when you wake in your biological night. A new wake time needs days of the same schedule.
- Sleep inertia. It can occur after each sleep period, and it fades.
Speak to a doctor if you sleep 7 to 8 hours on a regular schedule and are still very tired for weeks.
Which alarm helps with an early wake time?
An alarm cannot give you more sleep. It can help you get up at the time that you set, and keep that time each day.
Waker is an iPhone alarm app. When your alarm rings, you tap “Talk to Waker” and have a voice conversation about your day. There is no snooze button. In the evening, a feature named Tonight asks what tomorrow holds, in about twenty seconds, and your morning call starts with that. You can select wake-up days and grow a streak for each morning that you finish your conversation. Waker is not a very loud alarm. If you do not hear alarms, it is the wrong tool for you. No study has tested if a conversation makes an early wake time easier.
For more steps, see how to wake up without falling back asleep and how to stop snoozing.
Common questions
How long does it take to adjust to an early wake time?
We found no single researched number. It depends on the size of the change. Keep the same wake time each day, also on weekends, because a change of more than about one hour can disrupt your body clock.
Can I wake up early if I go to bed late?
You can for one day. If you do it regularly, the lost sleep adds up. The National Heart, Lung, and Blood Institute calls this sleep debt.
Is it bad to feel groggy when I wake up?
No. Grogginess for 15 to 30 minutes is normal. It is named sleep inertia.
Does a nap help?
A short nap can help on a day after a short night. A long or late nap can make it harder to fall asleep in the evening.
Sources
- How Much Sleep Is Enough. National Heart, Lung, and Blood Institute.
- Healthy Sleep Habits. National Heart, Lung, and Blood Institute.
- Sleep inertia: current insights. Hilditch and McHill, Nature and Science of Sleep, 2019.
- Evaluate the effectiveness of cognitive stimulation and physiological dynamization on sleep inertia. Beauchamps and colleagues, Frontiers in Physiology, 2026.
- Is snoozing losing? Why intermittent morning alarms are used and how they affect sleep, cognition, cortisol, and mood. Sundelin, Landry and Axelsson, Journal of Sleep Research, 2024.