Aging, Beta Blockers, and Thermoregulatory Responses
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Ambient Heat.
- Who it may be relevant to
- Registry conditions: Heat Stress, Aging. Basic parameters: from 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- United States
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
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.
Detailed description
Older individuals are more likely to die or become ill during heat waves. During the 1995 Chicago heat wave, there was 35% increase in hospital admissions for individuals older than 65 years of age. Moreover, adults over the age of 65 have a heat-related death rate that is more than double any other age group. Therefore, with an increasing elderly population that is expected to rise by 60% (to 78 million) by 2035, the causes of this excess mortality must be understood to better protect the ageing United States population. It is notable that selective and non-selective beta blocker drugs are commonly prescribed to older individuals with cardiovascular diseases. In younger individuals exposed to a heat stress, beta blocker administration reduced whole-body sweat rate and skin blood flow responses resulting in greater increases in core body temperature. Notably, nothing is known regarding the effects of beta blockers on thermoregulatory responses during heat exposure in older individuals.
This project will evaluate core body temperature responses to selective and non-selective beta blocker drugs during simulated heat wave exposure in older individuals.
Interventions
- Other Ambient Heat
Subjects will spend 3-hours in a heat chamber at 41°C and 40% humidity.
Primary outcome measures
- Internal temperature [Time frame: Continuously throughout the 3-hour heat exposure.]
- Whole body sweat rate [Time frame: Nude body mass will be measured before and after the 3-hour heat exposure.]
Secondary outcome measures (2)
- Heart rate [Time frame: Continuously throughout the 3-hour heat exposure.]
- Arterial blood pressure [Time frame: Continuously throughout the 3-hour heat exposure.]
Eligibility criteria
Inclusion criteria
- Healthy and free of any significant medical problems
- Normal resting electrocardiogram
- 65+ years of age
- Controlled cholesterol of less than 200 mg/dl
- Controlled blood pressure of less than 140/90 mmHg
Exclusion criteria
- 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
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Randomized
- Model
- Crossover
- Masking
- Double blind
- Primary purpose
- Basic science
Study locations
United States · 1 center
- IEEM Texas Health Presbyterian Hospital Dallas — Dallas
Identifiers
NCT: NCT06582680 · STU-2024-0644