Aging, Beta Blockers, and Thermoregulatory Responses

NCT06582680 | Recruiting Phase 4 FDA Drug

• 1 other identifier: STU-2024-0644
• Study Type: interventional
• Target: 22
• Locations: 1 country
• Sites: 1

Brief Summary

This study will test the hypothesis that the drugs propranolol and metoprolol will result in greater increases in core body temperature during 3 hours of extreme heat exposure in older adults.

Conditions

Heat Stress; Aging

Outcome Measures

Primary Outcomes (2)

• Internal temperature

  The change in internal temperature to the 3-hour heat exposure will be measured.

  Continuously throughout the 3-hour heat exposure.

• Whole body sweat rate

  Whole body sweat rate will be measured via changes in pre/post nude body mass.

  Nude body mass will be measured before and after the 3-hour heat exposure.

Secondary Outcomes (2)

• Heart rate

  Continuously throughout the 3-hour heat exposure.

• Arterial blood pressure

  Continuously throughout the 3-hour heat exposure.

Study Arms (6)

Placebo, then Propranolol, then Metoprolol

EXPERIMENTAL

Other: Ambient Heat

Placebo, then Metoprolol, then Propranolol

EXPERIMENTAL

Other: Ambient Heat

Propranolol, then Placebo, then Metoprolol

EXPERIMENTAL

Other: Ambient Heat

Propranolol, then Metoprolol, then Placebo

EXPERIMENTAL

Other: Ambient Heat

Metoprolol, then Placebo, then Propranolol

EXPERIMENTAL

Other: Ambient Heat

Metoprolol, then Propranolol, then Placebo

EXPERIMENTAL

Other: Ambient Heat

Interventions

Ambient Heat OTHER

Subjects will spend 3-hours in a heat chamber at 41°C and 40% humidity.

Metoprolol, then Placebo, then Propranolol; Metoprolol, then Propranolol, then Placebo; Placebo, then Metoprolol, then Propranolol; Placebo, then Propranolol, then Metoprolol; Propranolol, then Metoprolol, then Placebo; Propranolol, then Placebo, then Metoprolol

Eligibility Criteria

• Age: 65 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Older Adult (65+)

You may qualify if:

• Healthy and free of any significant medical problems
• Normal resting electrocardiogram
• + years of age
• Controlled cholesterol of less than 200 mg/dl
• Controlled blood pressure of less than 140/90 mmHg

You may not qualify if:

• Known diseases or other chronic conditions requiring regular medical therapy including cancer, diabetes, neurological diseases, uncontrolled hypertension, and uncontrolled hypercholesterolemia
• Serious abnormalities detected on routine screening
• Taking prescribed medications or over-the-counter medications that have known influences on either cardiac function or sweating
• Current smokers, as well as individuals who regularly smoked within the past 3 years
• body mass index ≥31 kg/m2

Sponsors & Collaborators

• University of Texas Southwestern Medical Center: lead

Study Sites (1)

IEEM Texas Health Presbyterian Hospital Dallas

Dallas, Texas, 75231, United States

RECRUITING

MeSH Terms

Conditions

Heat Stress Disorders

Condition Hierarchy (Ancestors)

Wounds and Injuries

Study Officials

• Craig Crandall, PhD

  Univ of Texas Southwestern Med Ctr

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Erin Harper, MS

CONTACT

214-345-4737; erinharper@texashealth.org

Courtney Kirby, RN

CONTACT

214-345-6502; courtneykirby@texashealth.org

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Neither the participants nor the researchers will know whether the participant received the placebo or one of the beta blocking drugs. Masking will be performed by the research nurse who will know which drug the participant received.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Internal Medicine

Model Details: We will first collect participant demographics, medical history, anthropometrics (body mass, height and composition). Individuals will be exposed to 3 hours in a hot environmental condition after receiving the placebo, propranolol, or metoprolol. Prior to entering the environmental chamber, baseline data will be collected while resting in a thermoneutral environment. Drug or placebo will be administered. Participants will then enter the environmental chamber and will be seated in a semi-recumbent position on a chair with breathable fabric to minimize impediments to heat dissipation. Periodically throughout the simulated heat-wave participants will lightly exercise to simulate metabolic heat production associated with activities of daily living (\~3 metabolic equivalents; METS). Throughout the heat-wave simulation trials we comprehensively evaluate the thermoregulatory and cardiovascular responses.

Study Record Dates

• First Submitted: August 30, 2024
• First Posted: September 3, 2024
• Study Start: October 4, 2024
• Primary Completion (Estimated): September 30, 2026
• Study Completion (Estimated): September 30, 2026
• Last Updated: October 23, 2025

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)