Medically reviewed by:
Dr. Shiyan Ooi
,
School of Medical Sciences, University of Manchester
Adjusting your sleep schedule can throw off your routine. Maybe you need to wake up at 5 a.m. to catch an early flight, or perhaps your new puppy needs morning walks.
Use our sleep cycle calculator to ensure you’re getting enough rest. The calculator determines when to go to bed or wake up based on how much sleep you need.
Modern life is busy. It’s tempting to sleep fewer hours, so you have more time to get work done.
However, how long you spend in bed dramatically impacts your overall health. Carrying a sleep debt can lead to fatigue, impaired judgment and reaction time, irritability, headaches, and a weakened immune system. It’s also associated with an increased risk of obesity and cardiovascular disease.
These consequences are severe, but they may be hard to spot when you’re in the thick of the experience. For instance, fatigue may become your normal state if you're chronically sleep-deprived. You may not realize that you’re so tired.
Oversleeping can be just as problematic. Researchers have found that people who sleep too much— more than nine hours a night —are more likely to have problems with cognitive function, memory, and concentration. They’re also prone to depression and heart disease.
However, while it seems clear that lack of sleep can cause health issues, the cause and effect are often reversed with oversleeping. Medical or psychological problems likely trigger prolonged sleep episodes in many cases. ‘When should I wake up?’ has a different answer when you’re sick.
Generally, sleep needs vary by age. Infants typically require 14 - 17 hours of sleep, while someone over 65 may function well on seven to eight hours.
Everyone else falls somewhere in-between. Most adults need seven to nine hours of sleep each night. However, this range isn’t set in stone.
Some people can get by with six hours of sleep a night and feel fine. Others need as much as 10 or 11 hours of rest to reach their peak level of alertness during the day.
Experimenting is the best way to figure out your ideal amount of sleep. Keep a sleep diary and pay attention to how you feel after different lengths of sleep.
To achieve the necessary amount of sleep, it’s important to understand sleep cycles. A full cycle comprises four stages ranging from light dozing to REM sleep and back again.
A question like ‘how much REM sleep do I need?’ will only give you part of the answer when determining how long to sleep. A better idea is to calculate how many sleep cycles you wish to go through.
Each complete cycle takes about 90 minutes to two hours. If you want seven hours of restful slumber, you should aim for four to five sleep cycles.
If you need to be awake at a specific time—for an event, flight, or just to feel less tired before work—the easiest way to calculate your bedtime is to think in sleep cycles. Below we’ve calculated some suggested bed times, including 15 minutes to fall asleep.
Getting adequate rest is a priority for good health. These tips can help you get the sleep your body needs:
Try to go to bed and wake up simultaneously on weekdays, weekends and holidays. This will help your body get into a natural rhythm.
Make sure your bedroom is dark, quiet, and comfortable. Too hot or cold can interfere with your sleep quality.
Avoid screen time 30 minutes before bed, and opt for calming activities like reading or listening to soft music instead.
Sleep Reset can help you improve your sleep when these tips aren’t enough. Our program helps you reset your patterns and get better rest.
With Sleep Reset, you can develop habits that will have a lasting positive impact on your quality of life. Our members report an average 88-minute increase in their sleep time and three fewer awakenings per night.
Ready to take control of your sleep? Take the sleep assessment for personalized recommendations to help you sleep better.
Dr. Shiyan Ooi
Dr. Shiyan Ooi is a medical doctor with over a decade of experience treating patients with chronic conditions. She graduated from the University of Manchester with a Bachelor of Medicine and Surgery (MBChB UK) and spent several years working at the National Health Service (NHS) in the United Kingdom, several Singapore government hospitals, and private functional medicine hospitals. Dr. Ooi specializes in root cause analysis, addressing hormonal, gut health, and lifestyle factors to treat chronic conditions. Drawing from her own experiences, she is dedicated to empowering others to optimize their health. She loves traveling, exploring nature, and spending quality time with family and friends.