The ideal bedroom: temperature, light, mattress and pillow

Your bedroom is probably too warm

Tip: Keep your bedroom cool (about 16–19 °C) and adjust your bedding.

Your core body temperature drops as you fall asleep. A room that is too warm holds that back and causes more waking. The ideal temperature does depend on bedding, clothing and the person.

How to apply it: Turn the heating down at night, ventilate during the day and choose a duvet that suits the season.

Source: Okamoto-Mizuno & Mizuno, 2012, Journal of Physiological Anthropology.

Even a little light during sleep has consequences

Tip: Make the room truly dark, with blackout curtains and no standby lights.

One night of sleep with moderate light (about 100 lux, like a lamp in the room) raised the heart rate at night and gave more insulin resistance the next morning than sleeping in the dark, even though participants formally slept the same number of hours.

How to apply it: Tape over charging lights, use blackout curtains or a sleep mask, and do not leave a TV or lamp on.

Source: Mason et al., 2022, PNAS.

Fresh air in your bedroom = better rested

Tip: Open a window a crack or ventilate well before you go to sleep.

In a Danish study, people slept better and performed better on attention tasks the next day in a well-ventilated bedroom (lower CO₂) than in a poorly ventilated one.

How to apply it: Leave the door or window ajar when the weather allows. During the day, open all windows for a good quarter of an hour.

Source: Strøm-Tejsen et al., 2016, Indoor Air.

Noise disturbs your sleep, even when you don’t notice

Tip: Dampen sound with earplugs, closed windows or a soft, steady sound source.

Night-time noise can trigger physical reactions (heart rate, blood pressure, brief awakenings) without waking you up. The World Health Organization warns about the health effects of noise at night. In hospital studies, earplugs and a sleep mask improved sleep.

How to apply it: Try soft earplugs, close windows on the street side or switch on a fan for a steady sound.

Source: Basner et al., 2014, The Lancet. Hu et al., 2015, Cochrane Database of Systematic Reviews (ICU patients).

A mattress doesn’t have to be rock-hard

Tip: Choose a mattress of medium firmness and test it for at least 10–15 minutes.

In a randomised study of people with chronic low back pain, a medium-firm mattress did better than a firm one. A review showed that medium-firm mattresses often score best for sleep quality and comfort.

How to apply it: Test it in your own sleeping position. Your spine should stay straight when you lie on your side, without your shoulder or hip sinking in or pressing too hard.

Stomach sleeper? Read sleeping with back pain or view SleepLab One, with a firm base for your pelvis.

Source: Kovacs et al., 2003, The Lancet. Radwan et al., 2015, Sleep Health.

An old mattress can cost you your night and your back

Tip: Replace your mattress if it is sagging, lumpy or older than about 8–10 years.

In an American study, participants experienced less back pain, better sleep and less stress after 28 days on new medium-firm bedding. A mattress gradually loses support and comfort.

How to apply it: Check for dips, waking up in pain or sleeping better elsewhere (hotel, staying with friends). If so, replacing it is worth considering.

Thinking of replacing yours? View SleepLab One and the sizes.

Source: Jacobson et al., 2009, Journal of Chiropractic Medicine.

The wrong pillow height gives you neck pain

Tip: Choose a pillow that keeps your neck in line with your spine.

In side sleepers, pillow height made a difference to neck symptoms and sleep quality. A pillow that is too high or too low leaves your neck crooked all night.

How to apply it: Side sleepers need a higher pillow (about shoulder width), back sleepers a lower one. Ask someone to take a photo of you on your side to see whether your neck is straight.

Stomach sleeper? Then the rule is: as thin as possible. Read stomach sleeping and neck pain.

Source: Gordon, Grimmer-Somers & Trott, 2009, Manual Therapy.

Your bed is for sleeping, not for working

Tip: Use your bed only for sleep and intimacy.

Stimulus control is a core part of insomnia treatment: you teach your brain to associate the bed with sleeping instead of worrying, working or scrolling.

How to apply it: Work, eat and watch TV elsewhere. If you lie awake for longer than about 20 minutes, get up for a while and go back to bed as soon as you feel sleepy.

Source: Morin et al., 2006, Sleep (AASM review).

Looking at the clock makes you more awake

Tip: Turn your alarm clock around or put it out of sight.

Clock-watching at night is linked to more worrying about sleep (“only 4 hours left!”) and often goes together with insomnia. The tension it causes keeps you awake.

How to apply it: Set your alarm and turn it around. If you know the alarm will go off, you do not need to know the time.

Source: Tang, Schmidt & Harvey, 2007, Journal of Behavior Therapy and Experimental Psychiatry.

Your dog in bed: is that OK?

Tip: Preferably let your pet sleep in its own spot in the bedroom, not in your bed.

Research found that a dog in the bedroom had little effect, but a dog in the bed lowered sleep efficiency somewhat. The differences were small.

How to apply it: Give your pet a basket next to the bed. If you keep waking up, try a night or two with it elsewhere.

Source: Patel et al., 2017, Mayo Clinic Proceedings.

A weighted blanket can bring calm

Tip: Try a weighted blanket of about 10% of your body weight.

In a randomised study of people with a psychiatric diagnosis and insomnia, a weighted blanket reduced the severity of insomnia. It is not a miracle cure and the study was limited to a specific group.

How to apply it: Choose a blanket you can easily push off yourself. If you notice nothing after 2–3 weeks, there is no need to spend more money on it.

Source: Ekholm et al., 2020, Journal of Clinical Sleep Medicine.

Sharing a bed, separate duvets?

Tip: Share your bed, but consider a duvet each if your partner sleeps restlessly or runs at a different temperature.

Couples who slept together had more and more stable REM sleep. At the same time, lack of sleep leads to more arguments. A duvet each is a practical solution for differences in temperature and movement, even though there is no direct study on it.

How to apply it: Try two duvets on one mattress and make sure you do not disturb each other when lying awake.

Source: Drews et al., 2020, Frontiers in Psychiatry. Gordon & Chen, 2014, Psychological Science.