What changes time to fall asleep

Minutes from lights out to sleep. Oura calls it Latency.

Every page below says it can change this metric. Strongest evidence first. Each page's "Effect on your sleep score" section says how much and how sure we are.

AlcoholAlcohol can help you fall asleep, then breaks up the second half of the night, cuts REM sleep, raises your heart rate and lowers HRV. Less, and earlier, is better.
- Evidence: Strong
- Medium effort
- Free
- Works: tonight
Caffeine cutoffHave your last coffee at least 9 hours before bed. Caffeine cuts sleep and deep sleep even when you fall asleep fine.
- Evidence: Strong
- Low effort
- Free
- Works: tonight
How sleep worksTwo systems decide when you get sleepy and how deeply you sleep. Almost every tip on this site works through one of them.
- Evidence: Strong
- Low effort
- Free
- Works: 1 week
Sleep restrictionSpend less time in bed so the time you do spend is asleep. A core part of CBT-I, with clear rules and real side effects.
- Evidence: Strong
- High effort
- Free
- Works: 3–4 weeks
What "good sleep" meansEnough hours, falling asleep without a fight, few wake-ups, regular times, and feeling alert in the day.
- Evidence: Strong
- Low effort
- Free
- Works: 1 week
Body scan and cognitive shuffleTwo in-bed techniques for a tense body or a busy mind. Relaxation has decent evidence; the cognitive shuffle has very little.
- Evidence: Some
- Low effort
- Free
- Works: 1–2 weeks
Building sleep pressureBe properly tired at bedtime. Stay awake long enough, move during the day, don't go to bed too early, and keep naps and caffeine from draining the pressure.
- Evidence: Some
- Low effort
- Free
- Works: tonight
ChronotypeYour chronotype is how early or late your body clock runs. It's partly genetic and changes with age, but light can move it by an hour or two.
- Evidence: Some
- Low effort
- Free
- Works: 1–3 weeks
Consistent wake timeGet up at the same time every day, weekends included. It anchors your body clock and makes falling asleep easier.
- Evidence: Some
- Medium effort
- Free
- Works: 1–2 weeks
Exercise timingRegular exercise helps sleep a little. Evening exercise is fine for most people; just finish hard sessions more than an hour before bed.
- Evidence: Some
- Medium effort
- Free
- Works: a few weeks
Hot shower or bathA warm bath or shower 1–2 hours before bed, at about 40–42.5 °C (104–108.5 °F), can help you fall asleep faster.
- Evidence: Some
- Low effort
- Free
- Works: tonight
How accurate are wearables?Sleep trackers are good at telling sleep from wake and at total sleep time. They are weaker at spotting time awake and at sleep stages.
- Evidence: Some
- Low effort
- Free
- Works: today
Jet lagJet lag is your body clock running on home time after you fly. Timed light, a shifted sleep schedule and, where allowed, melatonin can cut it short.
- Evidence: Some
- Medium effort
- Low cost
- Works: 2–7 days
MelatoninMelatonin is better at shifting your body clock than at knocking you out. For sleep onset it saves about 7 minutes on average. Low doses work; labels are often wrong.
- Evidence: Some
- Low effort
- Low cost
- Works: 1–3 days for timing shifts
Morning lightGet outside in daylight soon after you wake up. It sets your body clock earlier, so you get sleepy at a sensible time.
- Evidence: Some
- Low effort
- Free
- Works: 1–2 weeks
NapsA short nap of 10 to 20 minutes in the early afternoon can boost alertness without hurting your night. Long or late naps cost you deep sleep and make it harder to fall asleep.
- Evidence: Some
- Low effort
- Free
- Works: today
Screens and blue lightThe light from your phone matters less than you've heard. What you do on it, and how late it keeps you up, matters more. Dim the room, and put the phone down when you're sleepy.
- Evidence: Some
- Medium effort
- Free
- Works: tonight
Social jet lagSocial jet lag is the gap between when you sleep on workdays and on days off. Shrink it by keeping your wake time steady and getting morning light.
- Evidence: Some
- Medium effort
- Free
- Works: 1–2 weeks
Waking at 3 a.m.Brief wake-ups are normal. What to do when you can't get back to sleep, and when it's a sign of insomnia.
- Evidence: Some
- Low effort
- Free
- Works: 1–2 weeks
What sleep scores measureWhat goes into the sleep and readiness scores from Oura, WHOOP, Apple Watch and Garmin, according to each company's own documentation.
- Evidence: Some
- Low effort
- Free
- Works: today
Which habits change which metricA table of common sleep habits against the numbers your wearable shows, with the direction of each effect, how sure the research is, and where nobody has looked.
- Evidence: Some
- Low effort
- Free
- Works: tonight to 2 weeks
Bedding materialsCotton, linen, wool, silk, down and synthetics compared. Few good studies exist; choose by whether you sleep hot or cold, and don't expect mite-proof covers to fix allergies.
- Evidence: Weak
- Low effort
- Medium cost
- Works: tonight
Breathing techniquesSlow breathing at about 6 breaths a minute reliably raises HRV while you do it. Evidence that it improves sleep is small but promising; 4-7-8 and box breathing have even less.
- Evidence: Weak
- Low effort
- Free
- Works: tonight
Duvet weight and layeringMatch your duvet's warmth (tog) to the season, and use layers so you can adjust through the night. Weighted blankets have some evidence, but mainly in people with psychiatric conditions.
- Evidence: Weak
- Low effort
- Medium cost
- Works: tonight
Evening mealsEat dinner 3–4 hours before bed if you can (at least 2–3), keep it moderate in size, and go easy on spice and fat if you get reflux. Most studies on food and sleep are small.
- Evidence: Weak
- Low effort
- Free
- Works: tonight
GlycineThree grams of glycine before bed improved how people felt about their sleep in a few tiny Japanese trials, most run by a glycine maker. Promising, but far from proven.
- Evidence: Weak
- Low effort
- Low cost
- Works: 1–3 nights in trials
L-theanineL-theanine, an amino acid from tea, may slightly improve how well you feel you sleep. The effect is small, mostly self-reported, and many studies mixed it with other ingredients.
- Evidence: Weak
- Low effort
- Low cost
- Works: 2–8 weeks in trials
Late mealsFinish your last big meal at least 2 to 3 hours before bed, especially if you get heartburn. The evidence for sleep itself is thin and mixed.
- Evidence: Weak
- Medium effort
- Free
- Works: tonight
MagnesiumMagnesium might shorten the time it takes older adults to fall asleep a little, but the trials are few, small and low quality. Stay at or under 350 mg a day from supplements.
- Evidence: Weak
- Low effort
- Low cost
- Works: 2–8 weeks in trials
Orthosomnia, or worse sleep from score anxietyWorrying about your sleep score can make you feel worse and sleep worse. How to tell if it's happening to you, and what to do.
- Evidence: Weak
- Low effort
- Free
- Works: 1–2 weeks
SaunaMany regular sauna users say it helps them sleep, but no good trial has tested it. If you enjoy it, finish an hour or two before bed, drink water and skip the alcohol.
- Evidence: Weak
- Medium effort
- Medium cost
- Works: tonight
Wind-down routineGive yourself 30–60 minutes of dim, quiet, low-effort time before bed. A few parts are tested; most of it is sensible rather than proven.
- Evidence: Weak
- Low effort
- Free
- Works: 1–2 weeks