Heat Therapy in Older Hypertensive Women

NCT03857490 | Completed DMC

• 1 other identifier: STU 072018-091
• Study Type: interventional
• Target: 134
• Locations: 1 country
• Sites: 1

Brief Summary

The prevalence of hypertension is greater in older women than men, while the blood pressure (BP) control rate is lower in older women in US. Uncontrolled hypertension is a major risk factor for cardiovascular morbidity/mortality. Despite standard therapy and adherence to optimal drug regimens, \>50% of older hypertensive women still have inadequate BP control, and the control rate is further reduced with more aggressive BP targets recommended recently by the new Hypertension Guidelines. Thus, the effectiveness of drug treatment alone in the control of hypertension among older women is limited; hence, non-pharmacological approaches are also needed to help reduce BP in older hypertensive women. One adjuvant, non-pharmacological approach that offers promise in lowering BP is "heat therapy". Indeed, repeated whole-body heat exposure decreases BP in healthy humans. Whether this is also true after regional limb heating in hypertensive patients is unknown. The objectives of this research are to investigate the BP lowering effect of home-based lower leg heat therapy in older women with hypertension, and to examine the impact of this therapeutic modality on neural-vascular health in these patients. Aim 1 will test the hypothesis that chronic lower leg heat therapy combined with an antihypertensive drug is superior to drug treatment alone in lowering BP in older hypertensive women. We will randomly assign older hypertensive women to either an intervention group or a control group. Patients in the intervention group will perform 8 weeks of lower leg heat therapy via water immersion up to the knee in a circulated bath (water temperature 42°C, 4 times/week, 45 min/session), whereas patients in the control group will immerse their legs in a thermoneutral water bath (33°C) at the same frequency and duration. All patients will also receive a fixed dose of chlorthalidone (a diuretic, 25 mg orally daily). We will compare ambulatory BP, the BP control rate, and patient adherence and acceptability to treatment between the groups. Aim 2 will test the hypothesis that chronic lower leg heat therapy will improve nitric oxide bioavailability which can decrease sympathetic vasoconstriction and improve vascular function in older hypertensive women. We will use state-of-the-art techniques of microneurography, Doppler ultrasound, applanation tonometry, and cutaneous microdialysis to assess neural control, vasodilator function, and interstitial metabolites (i.e. nitrate and nitrite) indicative of basal nitric oxide bioavailability in all patients enrolled in Aim 1 before and after 8 weeks of heat therapy. Information obtained from this research project will guide evidence-based clinical practice. It is anticipated that our study may lead to revision of hypertension guidelines to incorporate home-based heat therapy as adjuvant to antihypertensive drug(s) for older women, as well as other patient populations.

Conditions

Essential Hypertension

Keywords

Ambulatory Blood Pressure Monitoring; Sympathetic Neural Control; Vascular Function

Outcome Measures

Primary Outcomes (3)

• Physiological parameter (awake ambulatory systolic pressure)

  24-hour ambulatory blood pressure monitoring will be performed and systolic blood pressure during the awake period before and after treatment will be compared in older women with hypertension.

  After 8 weeks of treatment.

• Physiological parameter (muscle sympathetic nerve activity)

  We will us the microneurographic technique to measure muscle sympathetic nerve activity in all older hypertensive women before and after treatment. Results will be compared between the intervention group and the control group.

  After 8 weeks of treatment.

• Physiological parameter (vascular function)

  We will use the Ultrasound Doppler technique to measure vascular function including arterial stiffness and endothelial function in older hypertension women before and after treatment. Results will be compared between the groups.

  After 8 weeks of treatment.

Study Arms (2)

Intervention

EXPERIMENTAL

Lower leg heat therapy via water immersion up to the knee in a circulated bath (water temperature 42°C, 4 times per week, 45 minutes per session) for 8 weeks.

Behavioral: Lower leg heat therapy

Control

PLACEBO COMPARATOR

Lower leg immerse in a thermoneutral water bath (33°C), 4 times per week, 45 minutes per session for 8 weeks.

Behavioral: Lower leg heat therapy

Interventions

Lower leg heat therapy BEHAVIORAL

Home-based 8 weeks of lower leg repeated heating.

Control; Intervention

Eligibility Criteria

• Age: 60 Years - 85 Years
• Gender Eligibility Details: All subjects in this research project will be women by design. Women between the ages of 60 and 85 years old will be enrolled.
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Women between the ages of 60-85 years with essential hypertension (systolic BP 140-179 and/or diastolic BP 90-109 mmHg)
• Must be able to understand and speak English

You may not qualify if:

• Illness or disabilities that preclude home-based heat therapy
• Any evidence of cardiopulmonary disease
• Severe hypertension (BP ≥180/110 mmHg; for safety reasons)
• Secondary hypertension
• Being on ≥3 antihypertensive agents
• Chronic kidney disease
• Diabetes mellitus or other systemic illness
• Any history of substance abuse (other than tobacco)
• Current cigarette smokers
• History of gouty arthritis
• Taking hormonal replacement therapy
• Being obese (body mass index ≥30 kg/m2)
• Endurance trained athletes
• Impaired cognitive function or diagnosed dementia

Sponsors & Collaborators

• University of Texas Southwestern Medical Center: lead

Study Sites (1)

Institute for Exercise and Environmental Medicine

Dallas, Texas, 75231, United States

Location

MeSH Terms

Conditions

Essential Hypertension

Condition Hierarchy (Ancestors)

Hypertension; Vascular Diseases; Cardiovascular Diseases

Study Officials

• Qi Fu, MD, PhD

  University of Texas Southwestern Medical Center

  PRINCIPAL INVESTIGATOR

• Steven Romero, PhD

  University of North Texas Health Science Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The randomization will be programmed with SAS Proc Plan and implemented via a user friendly web-based interface using REDCap. The biostatistician will be responsible for randomization; however, he/she will not have any contact with the patients and will not be involved in outcome measures. All investigators, except the research nurses, will be blinded to the group status of the patient during 8-week treatment and post-treatment testing. The research nurses will not be involved in data analysis and interpretation.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Medicine

Model Details: This is a randomized, placebo-controlled study. Older women with hypertension will randomly be assigned to either an intervention group or a control group (1:1 ratio). Patients in the intervention group will be required to perform 8 weeks of home-based lower leg heat therapy via water immersion up to the knee in a circulated bath (water temperature 42°C, 4 times per week, 45 min per session), whereas patients in the control group will immerse their legs in a thermoneutral water bath (33°C) at the same frequency and duration.

Study Record Dates

• First Submitted: February 22, 2019
• First Posted: February 28, 2019
• Study Start: July 29, 2019
• Primary Completion: September 17, 2025
• Study Completion: December 31, 2025
• Last Updated: March 6, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, CSR
• Time Frame: Data will remain available for a period of time no less than 10 years after the close of the study, per University of Texas System guidelines for records retention.
• Access Criteria: There are no specific access criteria IPD and no additional supporting information will be shared.

Locations

US (1)