Passive Heat Therapy and Age-associated Physiological Function

NCT03264508 | Completed DMC

• 1 other identifier: 16-0757
• Study Type: interventional
• Target: 25
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to determine the effects of 8-10 weeks of repeated hot water immersion ("heat therapy") vs. thermoneutral water immersion on vascular function in late middle-aged to older (55-79 years) adults.

Conditions

Aging

Keywords

endothelial function; arterial stiffness; heat; hot water immersion

Outcome Measures

Primary Outcomes (3)

• Brachial artery flow-mediated dilation

  Measure of endothelial function

  0 and 8 weeks

• Carotid-femoral pulse wave velocity

  Measure of central arterial stiffness

  0 and 8 weeks

• Mean arterial blood pressure

  Brachial artery blood pressure, measured in triplicate (and averaged) following 20 min of supine rest

  0 and 8 weeks

Secondary Outcomes (3)

• Cerebrovascular reactivity

  0 and 8 weeks

• Fluid cognition composite score

  0 and 8 weeks

• Motor function composite score

  0 and 8 weeks

Study Arms (2)

Heat therapy

EXPERIMENTAL

Hot water immersion 3-4x per week for 8-10 weeks

Behavioral: Heat therapy

Thermoneutral water immersion

SHAM COMPARATOR

Thermoneutral water immersion 3-4x per week for 8-10 weeks

Behavioral: Thermoneutral water immersion

Interventions

Heat therapy BEHAVIORAL

30 sessions (3-4x per week for 8-10 weeks) of hot water immersion in 40°C water, sufficient to raise body core temperature to 38.5°C.

Heat therapy

Thermoneutral water immersion BEHAVIORAL

30 sessions (3-4x per week for 8-10 weeks) of hot water immersion in 36°C water to prevent changes in body core temperature \>0.2°C.

Thermoneutral water immersion

Eligibility Criteria

• Age: 55 Years - 79 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Ability to provide informed consent.
• Aged 55-79 years. Women must be postmenopausal and not taking hormone replacement therapy within the past year.
• Sedentary to recreationally active: participating in vigorous aerobic exercise \<4x/wk for ≥ 3 yrs.
• Able to refrain from the use of dietary supplements, anti-inflammatory medications, and prescription medications for 24-48h prior to experimental testing.
• Generally healthy (no overt clinical disease), as determined by medical history, physical examination, blood and urine chemistries.
• Ankle-brachial blood pressure index \>0.7
• Total cholesterol \<240 mg/dl (\<6.2 mmol/L)
• Fasting plasma glucose \<126 mg/dl (\<7.0 mmol/L)
• Systolic blood pressure \< 160 mmHg and \>100 mmHg
• Glomerular filtration rate \> 60 ml/min/1.73 m2
• Mini mental state exam score \> 20 points
• Body mass index (BMI) \<30 kg/m2
• Weight stable in the prior 3 months (≤ 2 kg weight change) and willing to remain weight stable over the course of the study
• Free from alcohol dependence or abuse, as defined by the American Psychiatry Association, Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).

You may not qualify if:

• Current use of certain prescription medications that may interfere with thermoregulation and/or blood pressure control during heat stress. These include anti-hypertensives (in particular beta-blockers), nitrates and nitrites (e.g. nitroglycerin), PDE5 inhibitors (e.g. Viagra), anticholinergics (e.g. amitriptyline), and alpha-blockers (e.g. Flomax).
• Orthostatic hypotension
• Current or past smoking within the last 5 years
• Recent major change in health status within previous 6 months (i.e. surgery, significant infection or illness).
• Chronic clinical diseases (e.g., inflammatory bowel diseases/irritable bowel syndrome, coronary artery/peripheral artery/cerebrovascular diseases, diabetes, chronic kidney disease requiring dialysis, neurological disorders or diseases that may affect motor/cognitive functions \[multiple sclerosis, Parkinson's disease, polio, Alzheimer's disease, dementia or other brain diseases of aging\]).
• History of heat-related illness
• Open wounds or skin lesions. History of skin-related conditions or sensitivities to prolonged water immersion or exposure to pool chemicals.
• Blood donation within the past 2 months
• Inability to tolerate blood draws, intravenous catheters, and/or fingertip blood sampling, including past fainting in response to blood sampling.
• Rectal, anal, vaginal, or prostate surgery within the last 6 months, current or recent (within the last 6 months) hemorrhoids, or related concerns regarding use of rectal thermistor

Sponsors & Collaborators

• Douglas Seals: lead

Study Sites (1)

University of Colorado Boulder

Boulder, Colorado, 80309, United States

Location

Related Publications (1)

• Brunt VE, Howard MJ, Francisco MA, Ely BR, Minson CT. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. J Physiol. 2016 Sep 15;594(18):5329-42. doi: 10.1113/JP272453. Epub 2016 Jun 30.

  PMID: 27270841 BACKGROUND

MeSH Terms

Interventions

Diathermy

Intervention Hierarchy (Ancestors)

Hyperthermia, Induced; Therapeutics

Study Officials

• Douglas R Seals, PhD

  University of Colorado, Boulder

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: INVESTIGATOR
• Masking Details: Investigators collecting and analyzing data will be blinded to subject treatment arms. It is not possible to blind subjects.
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Professor of Distinction

Model Details: Randomized, controlled (parallel design), single-blind

Study Record Dates

• First Submitted: August 22, 2017
• First Posted: August 29, 2017
• Study Start: October 25, 2017
• Primary Completion: November 23, 2020
• Study Completion: June 1, 2021
• Last Updated: October 28, 2021

Record last verified: 2021-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)