Repeated thermal therapy improves impaired vascular endothelial function in patients with coronary risk factors.
Level 3 - non-randomized controlled study
Non-randomized pre-post interventional study with a healthy control comparison group
PubMed 11583886 · doi:10.1016/s0735-1097(01)01467-x
What was done
Twenty-five men with at least one coronary risk factor (hypercholesterolemia, hypertension, diabetes mellitus, or smoking; mean age 38 ± 7 years) and 10 healthy male controls (mean age 35 ± 8 years) were enrolled. Patients in the risk group were treated with a 60°C far infrared-ray dry sauna bath for 15 min and then kept in a bed covered with blankets for 30 min once daily for two weeks. Brachial artery diameter was measured via high-resolution ultrasound at rest, during reactive hyperemia (%FMD), and after sublingual nitroglycerin (%NTG) to assess endothelial function.
What was found
Baseline %FMD was significantly lower in the risk group than in controls (4.0 ± 1.7% vs. 8.2 ± 2.7%, p < 0.0001), while %NTG was similar (18.7 ± 4.2% vs. 20.4 ± 5.1%). Two weeks of sauna therapy significantly increased %FMD in the risk group from 4.0 ± 1.7% to 5.8 ± 1.3% (p < 0.001). %NTG did not change significantly (18.7 ± 4.2% to 18.1 ± 4.1%).
Why it matters
This study suggests that short-term repeated thermal therapy can partially restore impaired endothelium-dependent vasodilation in individuals with coronary risk factors.
Limits
The study had a small sample size (25 patients and 10 controls) and included only men. It lacked a randomized, unheated control group of patients with coronary risk factors, and long-term clinical cardiovascular outcomes were not evaluated.
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