We will test the hypothesis that increasing skin wetness, and thus evaporative cooling, will attenuate the increase in core body temperature and accompanying cardiac stress during heat wave conditions in individuals with congestive heart failure. Secondly, we propose that wearing a water-saturated T-shirt will also be beneficial to attenuate the increase in core body temperature and accompanying cardiac stress during heat wave conditions in individuals with congestive heart failure. To accomplish these objectives, individuals with congestive heart failure and otherwise healthy control individuals will be exposed to the simulated heat wave condition (hot and dry) with the following cooling modalities: A) control trial (no limb immersion or skin wetting), B) skin wetting only trial, and C) water-saturated T-shirt trial in a randomized crossover fashion. Thermoregulatory and cardiovascular responses will be evaluated throughout these simulated heat wave exposures. Primary outcomes variables will be skin and core temperatures, while secondary variables will include measures of cardiovascular stress, myocardial perfusion, heart rate, and echo-based measures of cardiac function.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
88
All participants will be exposed to a period of hyperthermia (hot and dry). In this condition, participants will not be given an experimental cooling modality.
All participants will be exposed to a period of hyperthermia (hot and dry). In this condition, participants will also wear a T-shirt that has been saturated with water.
All participants will be exposed to a period of hyperthermia (hot and dry). In this condition, participants will also be sprayed with water periodically.
Institute for Exercise and Environmental Medicine - Texas Health Presbyterian Hospital Dallas
Dallas, Texas, United States
RECRUITINGChange in Core Body Temperature while wearing a water-saturated T-shirt
Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill or rectal temperature via telemetric pill suppository or rectal thermistor. Core body temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in core body temperature.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Core Body Temperature in Skin-Wetting Trial
Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill or rectal temperature via telemetric pill suppository or rectal thermistor. Core body temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in core body temperature.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Core Body Temperature in Control Trial
Core body temperature will be measured from gastrointestinal temperature via an ingestible telemetric pill or rectal temperature via telemetric pill suppository or rectal thermistor. Core body temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in core body temperature.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Skin Temperature in while wearing a water-saturated T-shirt
Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin. Skin temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in skin temperature.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Skin Temperature in Skin-Wetting Trial
Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin. Skin temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in skin temperature.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Skin Temperature in Control Trial
Skin temperature will be measured from small temperature sensitive electrodes attached to the participant's skin. Skin temperature will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those temperatures will reflect the change in skin temperature.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Heart Rate while wearing a water-saturated T-shirt
Heart rate will be measured from ECG electrodes attached to the participant. Heart rate will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in heart rate.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Heart Rate in Skin-Wetting Trial
Heart rate will be measured from ECG electrodes attached to the participant. Heart rate will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in heart rate.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210minutes.)
Change in Heart Rate in Control Trial
Heart rate will be measured from ECG electrodes attached to the participant. Heart rate will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in heart rate.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210minutes.)
Rate Pressure Product while wearing a water-saturated T-shirt
Rate Pressure Product is calculated by multiplying Systolic Blood Pressure and Heart Rate.
Time frame: At the end of each heat wave exposure. Approximately 210minutes after the start of the heat wave simulation.
Rate Pressure Product in Skin-Wetting Trial
Rate Pressure Product is calculated by multiplying Systolic Blood Pressure and Heart Rate.
Time frame: At the end of each heat wave exposure. Approximately 210minutes after the start of the heat wave simulation.
Rate Pressure Product in Control Trial
Rate Pressure Product is calculated by multiplying Systolic Blood Pressure and Heart Rate.
Time frame: At the end of each heat wave exposure. Approximately 210minutes after the start of the heat wave simulation.
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Change in Cardiac Output while wearing a water-saturated T-shirt
Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography. Cardiac output will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in cardiac output.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Change in Cardiac Output in Skin-Wetting Trial
Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography. Cardiac output will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in cardiac output.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)
Cardiac Output in Control Trial
Cardiac output (how much blood is ejected from the heart) will be measured using echocardiography. Cardiac output will be measured at baseline as well as at the end of the hyperthermia simulation. The difference of those heart rates will reflect the change in cardiac output.
Time frame: Prior to and after each simulated heat wave exposure (approximately 210 minutes.)