June 05, 2018
1 min read

Warm baths improve sleep quality

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Bathing in moderate temperature water may improve sleep quality for elderly individuals with insomnia, according to findings that will be presented at SLEEP 2018, the Annual Meeting of the Associated Professional Sleep Societies this month.

“Previous cohort studies in Finland reported sauna bathing improve cardiovascular risk and all-cause mortality,” T. Yoshiaki, of the Nara Medical University School of Medicine, Kashihara City, Japan, told Healio Family Medicine. “More studies about associations between passive body heating and health benefits are needed.”

Researchers conducted a longitudinal study of 946 community-dwelling elderly individuals (mean age, 71.8 years). and evaluated participants’ sleep actigraphy, bathtub temperature and bathing diaries for 2 consecutive days.

Water temperature was measured at 1-minute intervals with a thermometer (Thennochron iButton, Maxim), according to the abstract. Additionally, study participants wore an actigraph (Achtiwatch2, Respironic Inc.) on their nondominant wrist to measure objective sleep quality and the amount of time spent soaking in the bath tub was self-reported through bathing dairies.

According to the abstract, the median bathing temperature was 40.8 degrees Celsius and participants spent a median of 12.4 minutes soaking in the bath tub. Researchers used the median value of both data sets to divide the information into moderate- and high-temperature bathing and short and long-time bathing.

When compared to non-bathing, participants who soaked in moderate temperature water experienced significantly shorter sleep onset latency (beta = –0.19; 95% CI, –0.348 to –0.047) as well as shorter wake after sleep onset (beta = –4.388; 95% CI, –8.676, to –0.1). However, length of time spent in the bathtub and high-temperature bathing did not exhibit significant associations with sleep onset latency or other sleep parameters.

“Moderate temperature bathing improved sleep onset latency,” Yoshiaki said in the interview. “When you take a bath ... set water temperature up to around 40.8 degrees C.” - by Marley Ghizzone


Tai Y, et al. Effect of bathing on objective sleep quality among elderly: a longitudinal analysis of repeated measurements in the Heijo-Kyo cohort. Presented at: SLEEP, the Annual Meeting of the Associated Professional Sleep Societies; June 2-6, 2018; Baltimore.

Disclosure: Healio Family Medicine was unable to confirm relevant financial disclosures prior to publication.