Passive heat therapy for cardiovascular disease: current evidence and future directions.
Level 1 - systematic review of randomized trials
Systematic review of 18 intervention studies across five databases
PubMed 39819110 · doi:10.1139/apnm-2024-0406
What was done
The authors systematically searched five databases, screening 2,913 records to identify 18 original research studies evaluating passive heat therapy in patients with cardiovascular disease (mean age 67 ± 10 years). Heat modalities included Waon therapy, balneotherapy, water-perfused trousers, Finnish sauna, and foot immersion. Interventions lasted 20 to 90 minutes per session, performed 3 to 7 times weekly for durations ranging from 2 to 8 weeks.
What was found
The abstract provides directional findings without pooled effect estimates or numerical metrics: - Heat therapy consistently improved left ventricular ejection fraction, flow-mediated dilation, brain natriuretic peptide (BNP) levels, New York Heart Association (NYHA) functional class, and 6-minute walk distance. - Beneficial changes in resting heart rate and resting blood pressure were infrequently observed. - Thermoregulatory outcomes were rarely reported; heat therapy may increase sweat rate during heat exposure and reduce resting core temperature, but adaptive skin blood flow responses were not observed.
Why it matters
Passive heat therapy offers a non-pharmacological, low-impact adjunctive approach that can enhance vascular function, functional capacity, and cardiac biomarkers in cardiovascular disease populations unable to perform regular exercise.
Limits
The abstract reports no quantitative meta-analytic effect sizes, confidence intervals, or specific risk-of-bias metrics. Interventions varied widely in heating modality, temperature exposure, duration, and frequency, and thermoregulatory and long-term safety endpoints were sparsely evaluated.
Cited by
- supports Hot tub immersion provides the same deliberate heat exposure benefits as a sauna.