Most adults need at least 7 hours of sleep per night, but how you sleep matters just as much as how long. Your position, bedroom setup, breathing, and daily habits all shape whether you wake up rested or groggy. Here’s what actually works.
How Much Sleep You Need by Age
The amount shifts significantly over a lifetime. Adults aged 18 to 60 need 7 or more hours each night. After 65, the window narrows slightly to 7 to 8 hours. Teenagers need 8 to 10 hours, and school-age kids need 9 to 12. Newborns top the chart at 14 to 17 hours.
These aren’t aspirational targets. They represent the amount your body needs to cycle through all the stages of sleep, including the deep sleep that repairs tissue and the REM sleep that consolidates memory and learning. A single sleep cycle takes about 80 to 100 minutes, and you need several complete cycles per night. Cutting your sleep short typically means losing REM sleep, since your body gets most of it in the second half of the night.
The Best Sleeping Position
Side sleeping is the best option for most people. It keeps your airway open, reduces snoring, and is the most protective position for your neck and spine. The one adjustment that makes a real difference: place a small pillow between your knees. Without it, the weight of your top leg pulls on your hip and can cause pain over time.
Back sleeping feels comfortable because you’re not putting weight on your joints, but it’s actually the worst position if you snore or have sleep apnea. Your tongue and jaw can fall backward and crowd your airway, making breathing harder. Stomach sleeping keeps the airway open but strains your neck and spine because your head is turned to one side all night.
Certain conditions call for specific positions. If you deal with acid reflux or GERD, sleep on your left side. Sleeping on the right side worsens heartburn symptoms. If you have mild sleep apnea, side or stomach sleeping helps keep airways from collapsing.
Matching Your Pillow to Your Position
A pillow that’s too thick or too flat forces your neck out of alignment with your spine, which leads to stiffness and poor sleep quality. Side sleepers have the biggest gap between their head and the mattress, so they need a high-loft pillow (over 5 inches, or roughly 4 to 6 inches depending on shoulder width). Back sleepers do best with a medium-loft pillow, around 3 to 5 inches, that gently supports the head without pushing it forward. Stomach sleepers should use a very thin pillow under 3 inches, or skip one entirely.
Set Your Bedroom Up for Sleep
Keep your bedroom between 60 and 67°F (15 to 19°C). Your body temperature naturally drops as you fall asleep, and a cool room supports that process rather than fighting it. A room that’s too warm is one of the most common and easily fixable causes of restless sleep.
Darkness matters too, but for a reason most people underestimate. Light exposure in the evening directly suppresses melatonin, the hormone that signals your body it’s time to sleep. In one study, two hours of exposure to an LED tablet screen caused a 55% drop in melatonin and delayed its onset by an hour and a half compared to reading a printed book. That same amount of evening light exposure can shift your entire internal clock by over an hour, making it harder to fall asleep and harder to wake up the next morning.
The practical takeaway: put screens away at least an hour before bed, and ideally two. If that’s not realistic, use your device’s night mode or dim it significantly.
Breathe Through Your Nose
Your body naturally prefers nasal breathing during sleep, and the difference is dramatic. Airway resistance nearly triples when you breathe through your mouth instead of your nose. In research measuring airway obstruction, subjects breathing orally had an average obstruction index of 43, compared to just 1.5 while breathing nasally. Simply opening your mouth during sleep, even without air flowing through it, increases the likelihood of your airway collapsing.
If you wake up with a dry mouth, sore throat, or the sense that you didn’t sleep well despite enough hours in bed, mouth breathing may be the issue. Nasal congestion from allergies or a deviated septum is a common cause worth addressing. Some people use mouth tape (a light adhesive strip across the lips) to encourage nasal breathing, though this works best after ruling out any nasal obstruction.
What to Avoid Before Bed
Caffeine has a half-life of about 5 to 6 hours, meaning half the caffeine from your afternoon coffee is still circulating in your bloodstream at bedtime. One study found that caffeine consumed six hours before bed still disrupted sleep, even when people didn’t notice it. A good cutoff is around 2 or 3 p.m. if you follow a standard evening bedtime.
Alcohol is trickier because it initially makes you drowsy. You may fall asleep faster and get slightly more deep sleep in the first half of the night, but the second half falls apart. Alcohol suppresses REM sleep, which is the stage that leaves you feeling rested and supports memory, learning, and concentration. The result is a night that feels long enough on paper but leaves you foggy the next day. This pattern, called rebound insomnia, often causes early waking and fragmented sleep in the hours before your alarm.
Building a Consistent Routine
Your body’s internal clock thrives on regularity. Going to bed and waking up at roughly the same time every day, including weekends, reinforces your circadian rhythm so that sleepiness arrives predictably. Shifting your schedule by even an hour or two on weekends can create a kind of social jet lag that makes Monday mornings feel genuinely harder, not just psychologically but physiologically.
A wind-down period of 30 to 60 minutes before bed helps signal the transition. This doesn’t need to be elaborate. Dimming the lights, reading something on paper, or doing light stretching all work. The goal is to separate the stimulation of your day from the stillness your brain needs to initiate sleep. If you’re lying in bed for more than 20 minutes without falling asleep, get up, do something quiet in low light, and return when you feel sleepy. Staying in bed while frustrated trains your brain to associate the bed with wakefulness.