Insomnia & Sleep: What the Research Actually Shows
A warm wind-down before bed has real research behind it — in baths and showers.
Far infrared for sleep is promising, small, and mixed.
When Trouble Sleeping Needs a Real Evaluation
If sleeping poorly happens most nights for a few months, or it's affecting your days, talk to a clinician. Loud snoring, gasping or pauses in breathing, or heavy daytime sleepiness can point to sleep apnea, which needs its own evaluation. Never drive drowsy. If low mood or hopelessness is part of this, tell your clinician — and in the US, call or text 988 in a crisis. Nothing on this page is a treatment.
Understanding Insomnia and Poor Sleep
Chronic insomnia affects roughly 1 in 10 adults, and far infrared gets marketed for sleep constantly. This page covers insomnia and general poor sleep. We didn't review sleep apnea, restless legs, or other sleep disorders, which each have their own medical evaluation.
Here's what's known about heat, far infrared, and sleep — starting with what works best.
What Has the Strongest Evidence for Chronic Insomnia
The American College of Physicians recommends cognitive behavioral therapy for insomnia (CBT-I) as the initial treatment for chronic insomnia in adults — a strong recommendation based on moderate-quality evidence.
CBT-I combines changes to how you think about sleep with behavioral steps like sleep restriction and stimulus control. It typically runs over several sessions, has far fewer side effects than sleeping pills, and can be delivered by a clinician or through online programs.
It doesn't work for everyone, but it's the standard to start with. The ACP also notes that sleep medications can carry serious adverse effects.
Ask your clinician about CBT-I first. Everything below is an extra, not a substitute.
What the Research Actually Shows
Warm Baths and Showers Before Bed
A systematic review and meta-analysis (Haghayegh et al. 2019, Sleep Medicine Reviews) found that warm-water bathing at about 40–42.5°C (104–108.5°F) was linked to better self-rated sleep quality and sleep efficiency.
When it finished 1 to 2 hours before bedtime — even for as little as 10 minutes — people fell asleep faster, by about 10 minutes on average.
The proposed reason: warming the body draws blood to the hands and feet, which helps the core cool down afterward, and a falling core temperature is a signal for sleep.
The caveats: it's water, not far infrared, and nobody has shown a far-infrared sauna session does the same. The researchers note that some studies found no benefit.
And the timing matters — the benefit was tied to heating 1–2 hours before bed, so heat close to bedtime could work against the cooling your body needs. How to time a far-infrared session for sleep hasn't been studied.
Far-Infrared Sleep Studies: Small and Mixed
Most far-infrared sleep research uses bedding or clothing, not saunas.
Bedsheets
A small pilot found 29 healthy adults sleeping on far-infrared-emitting bedsheets reported fewer insomnia symptoms than on placebo sheets (McCall et al.).
Pajamas
A sham-controlled pilot in 40 adults with poor sleep found no significant difference on its main sleep score. Both groups improved, and the sham group slightly more.
A secondary physical-fatigue measure favored the far-infrared pajamas, which the authors flagged as worth exploring (Chen et al. 2023, Int J Environ Res Public Health).
Blanket
In a 14-day double-blind study of 24 men over 45, only the far-infrared blanket group's sleep scores improved from their own starting point, and total sleep time didn't differ between groups.
The sleep-stage results came from a consumer wristband, which estimates stages rather than measuring them (Clocks & Sleep 2024).
Put together: a few small trials, mixed results, no one with a diagnosed insomnia disorder, and no sleep-lab testing.
What Is Not Established
That far-infrared sauna sessions treat insomnia, or what time of day or dose would be best. We didn't find a trial of that.
A randomized trial of evening sauna bathing in healthy volunteers is registered, but we found no results.
Figures like a “42% improvement in sleep scores” circulate for the blanket study; they come from a 24-person study and mostly reflect change from the group's own baseline, not a clean comparison with placebo.
Before You Use Heat for Sleep
- Don't skip the evaluation. Ongoing insomnia, snoring with breathing pauses, or heavy daytime sleepiness need a clinician — heat won't fix them.
- Timing: the warm-water benefit was tied to finishing 1–2 hours before bed. If you try a far-infrared session in the evening, earlier is more consistent with that evidence than right before sleep, and nobody has tested it. Stop if you feel wired or overheated.
- Alcohol and sleep medications: don't combine heat with alcohol or sedating medications without checking with your prescriber. Heat can add to dizziness and low blood pressure.
- Lightheadedness and falls: stand up slowly after a session, especially in the evening when you're already sleepy.
- Heart conditions or pregnancy: see our companion cardiovascular, conduction disease, and pregnancy pages before starting.
- If insomnia comes with persistent low mood or anxiety, bring it up with your clinician — see our Depression and Anxiety pages.
- This isn't a treatment and doesn't replace CBT-I or medical care.
What We Can Honestly Say
A warm, relaxing wind-down earlier in the evening is a low-risk practice with some evidence behind warmth in general. There's no proof that far infrared does more than other warmth, and no proof it treats insomnia. If sleep is a real problem, start with an evaluation and CBT-I.
For related context, see our companion Depression, Anxiety, Stress & Mood, Brain Fog, HPA Axis, and Cardiovascular pages.
Sources
Haghayegh et al. 2019 (Sleep Med Rev 46:124–135; doi:10.1016/j.smrv.2019.04.008); Chen et al. 2023 (Int J Environ Res Public Health 20(5):3870), which also describes McCall et al.; the DAZZEON far-infrared blanket study (Clocks & Sleep 2024;6(3):33); ACP guideline, Qaseem et al. 2016 (Ann Intern Med 165(2):125–133); AASM pharmacologic guideline for chronic insomnia; NCT06125639 (evening sauna bathing trial).
