Sleep is important—just look at the $70 billion industry devoted to it. But before you can improve your sleep, you need to ask: How much sleep do I need? Because, let’s be honest, a scented pillow spray can only do so much.
Finding out the amount of sleep you need varies per person, says sleep scientist Roy Raymann, Ph.D. and chief scientific officer at SleepScore Labs. “Some people are doing fine on a nightly seven hours of sleep, while others need more. Only very few people can do with less than five hours a night without negative health and well-being consequences.”
Even though the amount of sleep required is different for everyone, there are ways to find out what works best for you. The experts explain, below.
Why is sleep important?
If you’re waking up too early (or going to bed too late), it can affect you in ways you probably don’t even realise. “Sleep is a process that’s different as the night continues,” says Michael Breus, Ph.D., a sleep specialist and author of Good Night: The Sleep Doctor’s 4-Week Program to Better Sleep and Better Health.
The first third of the night, he explains, is the “deep sleep” stage when your body physically restores itself. While that’s important, you also need the last cycle of rapid eye movement (REM) sleep. That’s when we move information from short-term memory to long-term memory. “Physically, your body will be able to get up after three or four hours of sleep and function, but not particularly well,” Breus explains. “And mentally, you’re a mess.”
In short, sleep is when your body restores itself, both physically and mentally, so when you don’t have a quality sleep, it affects your body in several different ways. “It really hits you physically, emotionally, and cognitively when you don’t sleep,” says Breus. “It affects you cognitively, so you don’t think straight, your decision making slows down, and you have a greater likelihood of taking a high risk. From a physical standpoint, your reaction time slows down by almost a third. So driving a vehicle or operating machinery is a really bad idea when you’re sleep-deprived.”
Raymann echoes this, adding that not getting enough rest might lead to: “irritability, cognitive impairment, memory lapses, impaired moral judgment, decreased creativity, eye bags, cravings for unhealthy food, impaired immune system, increased risk of diabetes type two and obesity, and poor tissue healing.”
Your emotions will be heightened too
“Any emotion you have is worse,” when you haven’t gotten enough sleep, Breus says. For some, that could mean feelings of depression or anxiety. But it’s not all bad, Breus adds. “In some cases, happiness gets happier. Ever been so sleep-deprived that you thought something was funny and just can’t stop laughing?” he says. “All emotions get out of whack.”
How many hours of sleep do I need?
“How much sleep do I need?” is not an easy question to answer, Breus says, because everyone requires a different amount. “People’s genes will actually dictate how long they sleep and when they sleep,” he explains. Knowing your genetic chronotype—are you a night owl or an early bird, in other words—is important. Breus suggests using chronoquiz.com to learn yours.
Once you do that, there are ways to calculate how many hours of sleep you need. Breus recommends taking your normal wake-up time and counting backward to determine your bedtime. “In order to do that, you need to know that the average sleep cycle is approximately 90 minutes long and the average human has five of those sleep cycles,” Breus says. Five times 90 equals 450 minutes—or, seven and a half hours. So if you wake up at 6:30 a.m., try a bedtime of 11 p.m. (There’s a calculator on Breus’s thesleepdoctor.com that can help.)
That’s a general guideline, Breus says. If you find you need more or less sleep, adjust the bedtime.
If time allows and you’re dedicated to nailing down your sleep schedule, Raymann suggests taking two weeks off from watches, clocks, and alarms. “Go to bed when you’re tired; leave the bed when you are done sleeping,” he says. “At the end of those two weeks, you will more than likely set a routine that works for you, and the sleeping period is likely to reflect your personal sleep need.”
Tips for getting the sleep you need
Stick to one bedtime and wake-up time. Yes, that includes the weekends. “You want some type of circadian consistency,” Breus explains. A circadian rhythm is your internal 24-hour clock, or sleep-wake cycle, according to sleepfoundation.org. “The more consistent your circadian rhythm is, the better it functions.”
Set the mood
“First, make sure you have a comfortable, quiet, dark, and relatively cool setting,” Raymann advises. Your room should be comfortably cool, while the bed is comfortably warm. “I’d also advise getting yourself a good mattress, comfortable bedding, and make sure no light or noise can get between you and your sleep.”
No caffeine after 2 p.m.
Sorry, but that afternoon Starbucks run might need to go. “Caffeine has a half-life of six to eight hours,” Breus explains. If you stop drinking caffeine at 2 p.m., that means at least half will be gone by 8 p.m. which gives you a better chance to fall asleep when bedtime hits.
Stop drinking alcohol three hours before bed
Having a cocktail won’t disrupt your sleep, necessarily—just be aware of timing. “It takes the average human body approximately one hour to digest one alcoholic beverage,” Breus says. “If you have two glasses of wine with dinner, you should have two glasses of water and then wait two hours. Then you can go to sleep.” Why? Well, you pee more when you drink alcohol. “Once you pee, you’re stuck peeing all night, so you become dehydrated,” Breus explains. “There’s a really big difference between going to sleep and passing out.”
Build in a routine before bed
To have at least seven hours of sleep, you’ll want to give yourself some extra time to wind down at night. “Be aware that time in bed does not equal time asleep,” Raymann says. “For seven hours of sleep, you will need to reserve approximately eight hours in bed with the lights out.”
Exercise daily, but not within four hours of bedtime
“It’s a temperature issue,” Breus says. “Sleep follows the core body temperature cycle.” As he explains, at night your core body temperature hits its peak, then falls—which is a signal to your brain to release melatonin. “Melatonin is kind of like that key that starts the engine for sleep. If your body’s too hot, it doesn’t release melatonin. If you exercise close to bedtime, it raises your core body temperature. You want to avoid that.”
What if I’m still not sleeping?
Do you feel easily tired during the day? Dozing off unintentionally? Those are signs you should try sleeping longer, Raymann says: “If you cannot sleep longer, even if you try to, or you still feel tired even when sleeping longer, visit your M.D. to check if you sleep needs special attention. A sleep disorder might be the cause of your poor sleep or tiredness.”
Breus uses a rule of threes to help determine whether it’s time to seek medical help: “If you wake up more than three times a night for more than 30 minutes total, and that happens more than three times a week for more than three months, you need to see a doctor.”