Good sleep comes down to five things: getting enough hours for your age, keeping a consistent schedule, sleeping in the right position, setting up your bedroom properly, and timing your food and caffeine intake. Most adults need 7 to 9 hours per night, but duration alone doesn’t determine whether you wake up feeling rested. How you sleep matters just as much as how long.
How Many Hours You Actually Need
The right amount of sleep depends on your age. A National Sleep Foundation expert panel established these ranges after reviewing hundreds of studies:
- Infants (4 to 11 months): 12 to 15 hours
- Teenagers (14 to 17): 8 to 10 hours
- Adults (18 to 64): 7 to 9 hours
- Older adults (65+): 7 to 8 hours
These numbers represent time asleep, not time in bed. A healthy target is being asleep about 85 to 90 percent of the time you’re lying in bed. If you’re in bed for 8 hours but only sleeping 6, the problem isn’t your sleep duration, it’s your sleep efficiency. Interestingly, sleeping above 90 percent of your time in bed can also be a warning sign, since it sometimes indicates fragmented, poor-quality sleep driven by exhaustion.
Keep Your Schedule Consistent
Sleeping in on weekends feels like catching up, but it creates a phenomenon called social jet lag, the mismatch between your weekday and weekend sleep times. A study of nearly 1,000 adults found that this pattern is linked to worse mood, greater fatigue, and poorer overall health. Each hour of social jet lag was associated with an 11 percent increase in the likelihood of heart disease, and that held true regardless of how many total hours people slept.
Your body’s internal clock thrives on regularity. Going to bed and waking up at roughly the same time every day, including weekends, keeps your circadian rhythm aligned. This is one of the simplest changes you can make, and one of the most effective.
The Best Sleeping Position
Side sleeping is the best all-around position for most people. It keeps your airway open, which reduces snoring and helps with sleep apnea. Sleeping on the left side specifically discourages acid reflux by keeping your stomach positioned below your esophagus. For pregnant people, left-side sleeping promotes blood flow to the uterus and reduces swelling in the legs and ankles.
The trade-off with side sleeping is joint pressure. Your spine isn’t perfectly aligned on your side, so you may feel stiffness in your neck, hips, or shoulders, especially if you stay on one side all night. Placing a pillow between your knees can help keep your hips level.
Back sleeping keeps your spine the straightest and tends to cause less morning pain in the neck, back, and hips. But it’s one of the worst positions for snoring, sleep apnea, and heartburn. It’s also not recommended during the second and third trimesters of pregnancy, since the weight of the uterus can compress major blood vessels. People who carry extra weight in their midsection or have heart or lung conditions may also feel short of breath on their back.
Stomach sleeping isn’t recommended for most people. It forces your neck into a rotated position for hours and puts strain on the lower back. If you can’t break the habit, using a very thin pillow (or none at all) under your head reduces some of that strain.
Pillow and Spinal Alignment
Your pillow’s job is to keep your neck aligned with the rest of your spine, and the right choice depends on your position. Back sleepers need a pillow that supports the natural curve of the neck without pushing the head too far forward. Side sleepers generally need a thicker pillow to fill the gap between the shoulder and ear, keeping the head level. Stomach sleepers should use the thinnest pillow possible, or skip one entirely, to avoid hyperextending the neck.
Set Up Your Bedroom for Sleep
Temperature matters more than most people realize. Your body needs to cool down slightly to fall asleep and stay asleep. The ideal bedroom temperature for adults is 60 to 67°F (15 to 19°C). For babies and toddlers, aim slightly warmer: 65 to 70°F.
Light exposure is the other major factor. Any light suppresses melatonin, the hormone that regulates your sleep-wake cycle, but blue light from phones, tablets, and computers is especially disruptive. In one Harvard experiment, blue light suppressed melatonin for about twice as long as green light and shifted circadian rhythms by 3 hours compared to 1.5 hours. The practical guideline: stop looking at bright screens 2 to 3 hours before bed. If that’s not realistic, dimming your screens and using warm-toned lighting in the evening helps.
When to Stop Eating and Drinking Caffeine
Caffeine has a half-life of 4 to 6 hours, meaning half of what you consumed is still active in your body up to 6 hours later. It works by blocking the brain’s sleep-promoting receptors, the ones that respond to a chemical that naturally builds up throughout the day and eventually makes you drowsy. One study found that caffeine consumed even 6 hours before bedtime disrupted sleep, even when participants didn’t notice. For a standard evening bedtime, cutting off caffeine by 2 or 3 p.m. is a reliable rule.
Food timing matters too, especially if you’re prone to heartburn. Eating within 2 to 3 hours of bedtime triggers acid production, and lying down shortly after makes it easy for that acid to move into the esophagus. If you deal with acid reflux, leave at least 3 hours between your last meal and when you lie down.
How to Nap Without Ruining Your Night
Naps work best when they’re short. A nap under 20 minutes boosts alertness for a couple of hours afterward without cutting into your body’s natural sleep pressure, the buildup that makes you tired enough to fall asleep at night. Set an alarm for 15 to 20 minutes.
If you need a longer nap, aim for about 90 minutes, which is roughly one full sleep cycle. Waking up at the end of a cycle means you’ll likely surface from a lighter sleep stage, reducing that groggy, disoriented feeling called sleep inertia. Naps that fall between 20 and 90 minutes tend to wake you from deep sleep, leaving you feeling worse than before you lay down. Any grogginess from a well-timed nap typically clears within 15 to 30 minutes.