First of all: Why should you care if you’re getting enough sleep? We all know that a good night’s rest is important, but sometimes we need some reminding. In fact, some people think it’s a mark of pride to be able to function normally on less than six hours of sleep. That’s just nonsense.
Depriving yourself of sleep can result in a lingering feeling of tiredness, as well as a lack of energy. Staying up late might seem fun or necessary, but it comes with a price. Not getting enough sleep has been associated with a myriad of physical and mental health problems. It can even affect your social behavior!
Most people grew up believing that eight hours of sleep every night is essential, but that’s not necessarily true! The defining factor of the perfect amount of sleep is age. There are exceptions, of course, but you generally need less sleep the older you get.
Below is a list of optimal sleep durations by age group; according to a panel of prominent sleep specialists, scientists and researchers put together by the National Sleep Foundation. The data is by no means definitive or undisputed, though. The National Heart, Lung, and Blood Institute suggests a wider range of hours for both infants and pre-teens, and a narrower range for adults.
|Age Group||Recommended Hours of Sleep per Day|
|0-3 months||14-17 hours|
|4-11 months||12-15 hours|
|1-2 years||11-14 hours|
|3-5 years||10-13 hours|
|6-13 years||9-11 hours|
|14-17 years||8-10 hours|
|18-25 years||7-9 hours|
|26-64 years||7-9 hours|
|Over 64 years||7-8 hours|
The range of seven to nine hours for adults likely comes from the belief that one typical sleep cycle is completed every 90 minutes or so. This places the ideal sleep duration at five or six cycles, or seven and a half or nine hours. However, 90 minutes is an estimate at best.
Diet, genetics, medication, mental health, physical activity, and other fluctuating circumstances can affect the length of a sleep cycle. This is why a range of time—instead of an inflexible number of hours—is recommended. In fact, some studies point to seven hours as the ideal, although that would put wake up time right in the middle of a 90-minute cycle.
How do you figure out where you fall within the sleep duration range set for your age? The best way to do this is to keep a sleep diary. This is a easy way to improve sleep quality without making changes to your schedule until you’re sure you need to do it.
Take note of when you usually sleep and wake up, how many sleep interruptions you experience, and how you feel at different hours of the day. Try to duplicate conditions that are present during nights when you sleep better. You will eventually find that sweet spot: the optimal amount of sleep that’s unique to you.
If you’re curious and inclined to do more, consider taking a two-week vacation to run a personal experiment. Set a non-flexible bedtime and allow yourself to wake up without using an alarm. Try to sleep in a room that doesn’t let in sunlight, too; or use a sleep mask.
Observe how your body adjusts to not being woken up by an external influence every day. While the first week may give you varied results due to your body adjusting to the changes, past that you should start to see a pattern emerge. You’ll find yourself getting the same hours of sleep every night and waking up at roughly the same time every day.
Finally, it’s important to note that improving sleep quantity is only half of proper sleep hygiene; the other half is improving sleep quality. A good night’s rest must be a good balance between the two.