Sleep hygiene

The habits that make or break your sleep

Sleep hygiene isn't about cleanliness; it's about the habits and environment that set you up for quality sleep. And here's the thing: poor sleep hygiene is the number one cause of chronic sleep problems, ahead of any medical condition (Irish 2015). The term dates from the 1970s and the list has been refined since, but the core has not changed: a body clock that knows what time it is, a sleep drive that is allowed to build during the day, and a bedroom that does not fight either.

What actually works (backed by research)

• Same time, every day. A consistent bed and wake time (yes, weekends too) is the single most impactful change you can make. Your circadian clock thrives on routine, and in a 60 000-person UK Biobank analysis, regularity predicted mortality better than sleep duration (Windred 2024). If you can fix only one of the two, fix the wake time
• Morning daylight. Ten to thirty minutes of outdoor light within an hour of waking anchors the clock and advances the evening melatonin rise; it is the cheapest lever there is
• Cool bedroom. 18 to 20 °C is the sweet spot. Your core temperature needs to drop for sleep onset, which is also why a warm bath or shower an hour before bed helps: the rebound cooling afterwards does the work
• Darkness matters. Even dim light during sleep disrupts melatonin. Blackout curtains or a sleep mask make a real difference
• Screens off 1 hour before bed. Blue light suppresses melatonin production (Chang 2015). If you must use a device, at least enable a warm filter, and keep in mind that the content matters as much as the light: a work email at 23:00 costs more sleep than the screen's glow
• No caffeine after 2pm. Caffeine has a half-life of 5 to 6 hours. That 3pm coffee is still half-active at 9pm, and it reduces deep sleep even when you fall asleep without trouble
• Exercise regularly, but not within 2 to 3 hours of bedtime, or you'll be too wired to sleep. Earlier in the day, training is one of the strongest sleep improvers known
• Go easy on alcohol. Even a glass or two disrupts REM sleep, which is when your brain does its most important work, and fragments the second half of the night
• Bed is for sleep. If you are awake for more than about 20 minutes, get up, do something dull in dim light, and come back when sleepy. This is the core of the insomnia therapy with the best evidence, CBT-I, and it retrains the association between the bed and falling asleep
• Naps short and early. Twenty minutes before 15:00 refreshes without stealing sleep drive from the night; an hour at 18:00 does

What does not work as well as people think

Sleeping in at the weekend repays some short-term debt but shifts the clock, so Monday morning feels like jet lag. Melatonin supplements move the clock by an hour or so when taken in the early evening and do little as a sedative at bedtime. Alcohol shortens the time to fall asleep and ruins the rest of the night. And a fixed bedtime that is earlier than your body clock wants only produces long, frustrating minutes awake, which is the opposite of good hygiene.

See the impact in your data

The beautiful thing about tracking sleep with MyBodyAI is that you can actually see these changes working. Improve one habit, watch your Sleep Quality, Body Clock and Sleep Efficiency trends respond. Most people notice measurable improvement within 1 to 2 weeks, and the overnight heart rate and HRV usually move first: a lower resting pulse and a higher HRV on the nights after an alcohol-free week are the earliest reward.