Hydrotherapy for Stress and Relaxation: What Is Known

Urgent Guidance First

If you feel you might harm yourself or someone else, call or text 988 in the US, or call 911 in an emergency. A bath is not a treatment for a mental health crisis. If you are struggling to cope with stress, the NHS advises seeing a GP, and notes that talking therapies can help with stress. [1] In the US, ask your own clinician. See stress safety and when to get help.

Comfort Is Real; Proof Is Thinner

Many people find a warm bath relaxing, and that experience counts. The question here is narrower: do trials show that water practices lower stress in a way beyond that comfort, and compared with what? Studies of water cannot be blinded, and most stress outcomes are self-rated, so expectation and simply taking time out can affect the result. This page gives no water temperature or time to follow. Temperatures below are what researchers tested. Check with a clinician first if you have heart or blood pressure problems, are pregnant, or take medicines that affect blood pressure. See hydrotherapy safety.

Home Warm Baths

A Japanese randomized crossover trial of 38 people compared two weeks of immersion bathing in 40 °C water for 10 minutes with two weeks of showering only. [2] Visual-scale scores for fatigue, stress, pain and smiling were better after the bathing period, and mood-scale scores for tension-anxiety, anger and depression were lower. [2] This is a small, unblinded trial based on self-ratings, so it fits promising but limited.

Larger observational work points the same way without proving cause. A 2026 narrative review (17 of its 45 studies were on bathtub bathing) reported that habitual bathtub bathing, mainly studied in Japan, has been associated with selected stress-related markers, and said the evidence for domestic bathing is limited to observational studies of intermediate markers. [3] People who bathe often may differ in many other ways. The review also noted that hot-water immersion raises core body temperature and widens blood vessels near the skin. [3]

Spa and Balneotherapy Programs

• Korea, 16 weeks. A quasi-experimental (not randomized) study of 58 women aged 40 to 64 compared 20-minute hot spring immersions every two weeks with no spa exposure. Stress questionnaire scores differed between groups at week 16, but salivary cortisol and heart rate variability did not. [4]
• Lithuania, 11 days. A randomized trial in six medical spa centers enrolled 243 adults with moderate to high stress. All treatment groups improved from baseline, and no serious adverse events were reported. [5] Only the researchers were blinded, the program was a multi-part spa package rather than a home bath, and the abstract does not give the size of the difference against the control group. [5]

Both are spa-based programs. They show that people felt better after structured spa treatment. They do not show that a bath at home does the same. Promising but limited.

Cold Water and Stress

A 2026 meta-analysis of 13 studies of cold showers, cold-water immersion and winter swimming found estimates that generally leaned toward benefit for perceived stress and mood, but concluded the evidence does not establish an effect and that most studies had serious risk of bias. [6] Cold exposure carries its own risks: see cold showers: what research shows and cold shock. Do not use breath-holding or over-breathing in or near water. See breathwork safety.

Where We Found Nothing Usable

Proper evidence not found for a large, blinded or sham-controlled trial of a home warm bath or hot tub as a treatment for an anxiety disorder or chronic stress. We searched PubMed for warm bath, hot-water immersion, bathing, balneotherapy and spa trials with stress, anxiety, cortisol and heart rate variability outcomes. Mood and depression trials are covered in hydrotherapy for mood and depression claims.

Other

Ways to Ease Stress
The NHS lists breathing exercises among things to try for stress. [1] See breathing exercises for stress, relaxation techniques and how to relieve stress.