Heat Therapy for High Blood Pressure

Recruiting in Palo Alto (17 mi)

Overseen by Douglas R Seals, PhD

Age: 18+

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Academic

Recruiting

Sponsor: University of Colorado, Boulder

Must not be taking: Anticholinergics, Alpha-blockers, Beta-blockers, others

Disqualifiers: Obesity, Orthostatic hypotension, Atrial fibrillation, others

No Placebo Group

Trial Summary

What is the purpose of this trial?

This trial is testing if taking regular hot baths can improve blood pressure and blood vessel function in adults aged 50 and older. The idea is that hot water might help relax blood vessels and improve blood flow, which could lower blood pressure.

Will I have to stop taking my current medications?

The trial requires participants to refrain from using certain medications, such as dietary supplements, anti-inflammatory drugs, and some prescription medications, before and during water immersion visits. Specific medications like PDE5 inhibitors and nitrates have defined periods when they should not be taken around these sessions. It's best to discuss your current medications with the trial's medical team to see if adjustments are needed.

What data supports the effectiveness of the treatment Heat Therapy for High Blood Pressure?

Research shows that heat therapy, including Waon therapy, can lower blood pressure and improve blood vessel function. A study found that repeated Waon therapy sessions significantly reduced both systolic and diastolic blood pressure in patients with hypertension. ^{1 2 3 4 5}

Is heat therapy safe for humans?

Research on heat therapy, including Waon therapy and hot pack thermal therapy, shows it is generally safe for humans, with no significant changes in blood pressure and improvements in vascular function observed in studies. ^{1 2 3 6 7}

How does heat therapy differ from other treatments for high blood pressure?

Heat therapy, such as Waon therapy, is unique because it uses heat to improve blood flow and reduce blood pressure, unlike traditional medications that often target the heart or blood vessels directly. This therapy involves using a sauna or hot packs to induce vasodilation (widening of blood vessels), which can help lower blood pressure by improving circulation. ^{1 4 6 8 9}

Research Team

Douglas R Seals, PhD

Principal Investigator

University of Colorado, Boulder

Vienna E Brunt, PhD

Principal Investigator

University of Colorado, Boulder

Eligibility Criteria

This trial is for adults aged 50 or older with systolic blood pressure between 120-159 mmHg. Participants must be mentally capable of consent, not pregnant, weight stable, and willing to maintain their lifestyle throughout the study. They should be healthy enough for heat exposure but can't join if they have unstable heart conditions, take multiple anti-hypertensive drugs (except one or two), do intense regular exercise, have recent major health changes including surgery or COVID-19.

Inclusion Criteria

I am willing to be randomly assigned to a treatment group.

Free from alcohol dependence or abuse, as defined by the American Psychiatry Association, Diagnostic and Statistical Manual of Mental Disorders (DSM-IV)

I am healthy enough for heat stress therapy, as confirmed by my doctors.

Exclusion Criteria

You have open wounds or skin conditions that could be affected by being in water for a long time, like in a pool.

I have atrial fibrillation or flutter.

I have not donated blood in the last 2 months.

Trial Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo hot water immersion or thermoneutral water immersion approximately 3 times per week for 12 weeks

12 weeks

Approximately 36 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment, with assessments at 4 and 12 weeks post-treatment

12 weeks

2 visits (in-person)

Treatment Details

Interventions

• Heat therapy (Behavioural Intervention)
• Thermoneutral water immersion (Behavioural Intervention)

Trial Overview The study tests whether hot water immersion ('heat therapy') versus thermoneutral water immersion over approximately 12 weeks can lower blood pressure and improve vascular function in middle-aged and older adults.

Participant Groups

Group I: Heat therapy Experimental Treatment 1 Intervention

Hot water immersion \~3x per week for 12 weeks

Group II: Thermoneutral water immersion Placebo Group 1 Intervention

Thermoneutral water immersion \~3x per week for 12 weeks

Who Is Running the Clinical Trial?

University of Colorado, Boulder

Lead Sponsor

Trials

128

Recruited

29,600+

Matt Biggers

University of Colorado, Boulder

Chief Medical Officer since 2012

BS in Business Administration Management from Appalachian State University, MS in Sport Management from Georgia Southern University

Justin Schwartz

University of Colorado, Boulder

Chief Executive Officer since 2023

PhD in Physics from Florida State University

Findings from Research

Heat therapy significantly reduces mean arterial, systolic, and diastolic blood pressure, as shown in a systematic review of 15 studies involving various healthy and clinical populations.

In addition to lowering blood pressure, heat therapy improves vascular function, indicated by enhanced flow-mediated dilatation, suggesting it could be a valuable tool for preventing and managing cardiovascular disease risk factors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta-analysis. Pizzey, FK., Smith, EC., Ruediger, SL., et al.[2022]

In a study of 129 patients with chronic heart failure, Waon therapy significantly reduced cardiac events, with only 31.3% of patients experiencing such events compared to 68.7% in the control group over a 5-year follow-up period.

The overall survival rate for patients receiving Waon therapy was 84.5%, suggesting that this non-pharmacological treatment may improve prognosis in chronic heart failure patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Waon therapy improves the prognosis of patients with chronic heart failure. Kihara, T., Miyata, M., Fukudome, T., et al.[2022]

In a study involving 19 patients (11 in the treatment group and 8 in the control group), combining thermal biofeedback training with progressive muscle relaxation significantly reduced systolic blood pressure by 20.6 mmHg and diastolic blood pressure by 14.4 mmHg over four weeks.

In contrast, the control group that only received progressive muscle relaxation showed a tendency for blood pressure to increase, highlighting the added benefit of thermal biofeedback in managing essential hypertension.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effect of thermal biofeedback and progressive muscle relaxation training in reducing blood pressure of patients with essential hypertension. Hahn, YB., Ro, YJ., Song, HH., et al.[2019]

Whole-body hot pack thermal therapy (HPTT) was found to produce a significant increase in skin vasodilation similar to that of Waon therapy (WT), suggesting it could be an effective alternative for chronic heart failure treatment.

In a study involving 19 healthy men, both therapies resulted in similar dilation of the brachial artery, indicating that HPTT can achieve comparable cardiovascular benefits without the need for specialized sauna equipment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cardiovascular reactions for whole-body thermal therapy with a hot pack and Waon therapy. Kominami, K., Noda, K., Takahashi, N., et al.[2020]

Waon therapy, a repeated sauna treatment, significantly improved cardiac function in patients with chronic heart failure, as evidenced by an increase in left ventricular ejection fraction and exercise tolerance measured by the 6-minute walk test.

The therapy also enhanced endothelial function and reduced levels of neurohumoral factors like norepinephrine and brain natriuretic peptide, suggesting that improved endothelial function is a key mechanism behind the increased exercise capacity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of repeated sauna treatment on exercise tolerance and endothelial function in patients with chronic heart failure. Ohori, T., Nozawa, T., Ihori, H., et al.[2022]

Sauna therapy positively influences blood pressure and peripheral hemodynamics in patients with hypertension and coronary heart disease, suggesting it can help manage hypertonic regulation issues.

Patients tolerated sauna therapy well, showing good compliance, although it did not improve the pumping function of the left ventricle after heart surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Sauna therapy in coronary heart disease with hypertension after bypass operation, in heart aneurysm operation and in essential hypertension]. Winterfeld, HJ., Siewert, H., Strangfeld, D., et al.[2022]

In a study involving hypertensive patients treated with propranolol, both sauna baths and running exercises led to significant reductions in resting blood pressure and improvements in peripheral blood circulation over several weeks.

However, the therapeutic methods did not alter the hypertensive regulation during higher levels of physical exertion, indicating that while these treatments are beneficial at rest, they may not fully address blood pressure control during intense activity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Effect of sauna and walking series on blood pressure, peripheral microcirculation and performance behavior in essential hypertension]. Winterfeld, HJ., Strangfeld, D., Siewert, H.[2008]

References

1. United States pubmed.ncbi.nlm.nih.gov

Blood pressure-lowering effect of repeated Waon therapy in non-smokers with hypertension. [2021]

2. England pubmed.ncbi.nlm.nih.gov

The effect of heat therapy on blood pressure and peripheral vascular function: A systematic review and meta-analysis. [2022]

3. Netherlands pubmed.ncbi.nlm.nih.gov

Waon therapy improves the prognosis of patients with chronic heart failure. [2022]

4. United States pubmed.ncbi.nlm.nih.gov

Heat therapy in the management of heart failure. [2019]

5. United States pubmed.ncbi.nlm.nih.gov

The effect of thermal biofeedback and progressive muscle relaxation training in reducing blood pressure of patients with essential hypertension. [2019]

6. England pubmed.ncbi.nlm.nih.gov

Cardiovascular reactions for whole-body thermal therapy with a hot pack and Waon therapy. [2020]

7. United States pubmed.ncbi.nlm.nih.gov

Effect of repeated sauna treatment on exercise tolerance and endothelial function in patients with chronic heart failure. [2022]

8. Germany pubmed.ncbi.nlm.nih.gov

[Sauna therapy in coronary heart disease with hypertension after bypass operation, in heart aneurysm operation and in essential hypertension]. [2022]

9. Germany pubmed.ncbi.nlm.nih.gov

[Effect of sauna and walking series on blood pressure, peripheral microcirculation and performance behavior in essential hypertension]. [2008]