A nightly soak brought modest gains in sleep in patients with heart failure
STUDY: Hsu SM et al, Front Cardiovasc Med 2026
STUDY TYPE: Randomized controlled trial
FUNDING: MacKay Memorial Hospital, Taiwan
Background
Up to 75% of people with heart failure sleep poorly. Warming the feet dilates blood vessels, signaling sleep by reducing core body temperature.
Prior Evidence
Warm foot baths 1-2 hours before sleep improved subjective sleep quality in a 2025 analysis of 18 controlled studies involving 950 older adults. It took a week to see optimal results, and the best results were achieved with water temperatures ≤ 40°C and immersion times ≥ 10 min.
However, only one study used an active control, comparing it to reflexology (with similar results). Other studies compared it to wait list or treatment as usual.
The Study
- 86 outpatients with stable heart failure in Taiwan (average age 61, 81% men) were randomized; 74 finished.
- The footbath group soaked their feet in 42°C (108°F) water for 20 minutes, about an hour before bed, every night for 4 weeks. Controls received usual care.
- Both groups wore wrist sleep trackers. Outcomes were the Sleep scale (PSQI) and the Piper Fatigue Scale at 4 and 8 weeks.
Results
Sleep scale (PSQI) scores improved 1.3 points more in the footbath group at 4 weeks and 1.7 points more at 8 weeks. Most patients started near the cutoff for poor sleep.
Sleep trackers showed no change in total sleep time. Sleep efficiency rose up to 6% more than controls on 9 of 28 nights.
Fatigue fell 6 points more in the footbath group, but that group started with nearly double the fatigue. By week 4, the groups had similar scores.
Side Effects
No adverse effects were reported, but caution is in order with high temperatures. Avoid foot baths with neuropathy, poor circulation, lesions or skin disease in the legs or feet. The maximum safe temperature for a standard foot bath is 42°C to 43°C (108°F to 110°F), and most therapeutic warm soaks use 38°C and 40°C (100°F to 104°F).
Limitations
- No blinding or sham (compared to usual care)
- Baseline differences in fatigue
- Mostly men with mild symptoms
Practice Implications
- Consider foot baths for insomnia in older or medically ill.
- Avoid in patients with neuropathy, foot wounds, or poor circulation.
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
