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Temperature and air

64–68 °F (18–20 °C). Don't crank the AC into a noisy on/off cycle.

Cool is right — generally 64–68 °F — but personal. Heat exposure measurably increases wakefulness and reduces deep and REM sleep; a falling core temperature is one of the triggers for sleep onset. Some prefer colder so they can use a heavier blanket.

When this idea went viral people cranked the AC; now we consistently see the AC kicking on and off waking people via sound change. Dirty AC units also throw dander and particulates into the air; a stuffy nose leads to mouth breathing and hypopnic/apneic events. A fan blowing at your face dries your mouth.

Temperature-regulating covers help if you're running hot; if you're not, you're already fine. Pillow/mattress/ergonomics: mostly feel; no hard rules.

Sources · 3

Effects of thermal environment on sleep and circadian rhythmOkamoto-Mizuno K, Mizuno K · 2012Heat exposure increases wakefulness and reduces deep and REM sleep; humidity worsens it.The temperature dependence of sleepHarding EC, Franks NP, Wisden W · 2019Falling core temperature (via warm skin, cool room) is a trigger for sleep onset.Nighttime ambient temperature and sleep in community-dwelling older adultsBaniassadi A, Manor B, Yu W, Travison T, Lipsitz L · 2023Sleep efficiency was best between ~20–25 °C (68–77 °F) in older adults and dropped 5–10% as rooms warmed — cooler is better, personal range matters.

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Temperature & air

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Temperature and air?

64–68 °F (18–20 °C). Don't crank the AC into a noisy on/off cycle.

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Educational summary of published research, not medical advice. Screening scores are not diagnoses. If a score is elevated or you feel unwell, talk to a clinician.