Hot baths
- What it is
- How often you take a hot bath, set against the groups in a large Japanese study of tub bathing.
- How it is measured
- Over the last 4 weeks, a bath day is a day with at least 5 minutes of hot bath. The weekly average sits in one of the study's groups: 0–2 times a week, 3–4 times, or almost daily.
- How to read it
- Almost daily hot tub bathing went with a lower risk of cardiovascular disease than 0–2 times a week. In a lab trial, eight weeks of regular 40.5 °C baths improved how well arteries widen and lowered blood pressure.
- What it cannot tell you
- The cohort is observational and asked about habits once, at the start. People who bathe more may differ in other ways. The Japanese baths were typically around 40–42 °C and the trial used immersion to the waist or shoulders.
Sources
Every one of these ships inside the app, with the finding written out so you do not have to open the paper to know why it is there.
Ukai T, Iso H, Yamagishi K, et al. Habitual tub bathing and risks of incident coronary heart disease and stroke. Heart, 2020.
About 30,000 Japanese adults followed for about 20 years. Almost daily tub bathing, compared with 0–2 times a week, was associated with a 28% lower risk of cardiovascular disease.
doi.org/10.1136/heartjnl-2019-315752Brunt VE, Howard MJ, Francisco MA, Ely BR, Minson CT. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. Journal of Physiology, 2016.
Eight weeks of hot-water immersion at 40.5 °C raised flow-mediated dilation from 5.6% to 10.9% and lowered mean arterial pressure from 83 to 78 mmHg.
doi.org/10.1113/JP272453