Active clinical trials for "Heat Stress Disorders"

Arteries are flexible in their structure and function and change in response to a variety of factors. Endothelial cells, are the skin type cells that form a layer inside arteries, and they are very important for arterial health. When they work properly, they produce substances that make the artery enlarge and support a healthy environment; but when they do not work properly, they produce substances that make the artery constrict and lead to a harmful environment. We can measure the function of these cells using an ultrasound machine and a quick test. The application of heat has been shown to change the structure and function of arteries, but we need to understand how these changes happen before we can effectively use heat as a therapy. Limb heating protocols (e.g., leg bath), in contrast with whole-body heating modes (e.g., sauna), are appealing as therapies because they generally cost less and are easier to use; but evidence is needed to demonstrate that they work before widespread use can be considered. Imagine soaking your legs in a bathtub filled with warm water becoming part of the options you have for staying healthy. Clearly, there is a lot of potential for heat to be used as a therapy, particularly for people who are unable to, or have difficulty participating in other health interventions that are known to improve arterial, but we need to do this type of research before we are able to recommend warm foot baths for therapeutic purposes.

Climate change not only affects the planet's natural resources, but also severely impacts human health. An individual's ability to adequately cope with short- or long-term increases in ambient temperature is critical for maintaining health and wellbeing. Prolonged increases in temperature (heatwaves) pose a serious health risk for older adults, who have a reduced capacity to efficiently regulate body temperature. However, information regarding the impact of age on body temperature regulation during prolonged exposure to extreme heat is lacking, as is research on the effectiveness of interventions aimed at reducing heat strain in such situations. This project will address these important knowledge gaps by exposing healthy young and older adults to a prolonged (9 hour) heat exposure, with conditions representative of heatwaves in temperate continental climates. An additional cohort of older adults will complete the same heatwave simulation but will be briefly (2 hours) exposed to cooler conditions (22-23°C) mid-way through the session (akin to visiting a cooling centre or cooled location). The investigators will evaluate age-related differences in the capacity to dissipate heat via direct air calorimetry (a unique device that permits the precise measurement of the heat dissipated by the human body) and their effect on the regulation of body temperature. The investigators anticipate that older adults will exhibit progressive increases in the heat stored in the body throughout the simulated heatwave, resulting in progressive increases in body core temperature. Further, older adults exposed to brief-mid day cooling will rapidly gain heat upon re-exposure to high ambient temperatures. As a result, by the end of exposure body temperatures will be similar to the group not removed from the heat.

The study aims to investigate the effects of including regular heat therapy when included to exercise. Specifically, participants in the sauna intervention group will undergo 15 minutes of sauna exposure immediately after a 50-minute session of exercise, 3 times a week, while participants in the exercise intervention group will follow only the same exercise protocol. The 50-minute exercise session consists of 20 minutes of moderate intensity strength exercise, followed by 30 minutes of moderate-vigorous aerobic exercise on stationary bikes. This exercise intervention protocol was selected in order to meet and adhere to the recommended physical activity guidelines.

An individual's ability to adequately cope with short- or long-term increases in ambient temperature is critical for maintaining health and wellbeing. Prolonged increases in temperature (heatwaves) pose a serious health risk for older adults, who have a reduced capacity to regulate body temperature. Currently, however, there is a lack of information regarding how different environmental conditions experienced during heatwaves impact body temperature regulation and physiological function. This is particularly important in the context of ambient conditions in the home, where older adults spend the majority of their time. This project will address this important issue by exposing healthy older adults to prolonged (8-hour) simulated heatwaves comprising a range of environmental conditions representative of an actively cooled domicile through to a worst-case scenario (i.e., no capacity for home cooling). The investigators will directly measure their ability to regulate their body temperature and the associated impact on the autonomic control of the heart. The investigators anticipate that physiological strain will be mild during prolonged exposure to conditions below the currently recommended thresholds set by Toronto Public Health (26°C). However, at higher indoor temperatures, impairments in body temperature and cardiovascular regulation will be seen.

Israel ministry of defense is examining a new protective undergarment of GORE company (chempark fabric) for the police forces. The goal of this research is to perform a comparative experiment in order to evaluate the physiological strain induced by a BC protective undergarment under exercise-heat stress conditions.

This is primarily an experimental study investigating methods of temperature measurement / heat strain detection. In the calibration study, there are different skin temperature sensor types, and in the prediction study there are different methods for determining heat strain, including conventional methods (rectal, gastro-intestinal), the development of a prediction model, and an index based on heart rate variability.

Workplace heat exposure affects billions of people during their everyday work activities. Occupational heat stress impairs workers' health and capacity to perform manual labour. Therefore, the aim of this study was to observe the heat strain experienced by workers in occupational settings and test different strategies to mitigate it during actual work shifts in agriculture, manufacture, tourism, construction, and other services.

The aim of the study is to study the thermoregulatory responses under real life conditions, such as during wheelchair rugby and basketball matches. A further goal is to develop and validate a standardised field-based protocol, which induces the same thermoregulatory response as during a wheelchair rugby and basketball match. This knowledge allows to investigate strategies to reduce heat stress and to enhance exercise performance (e.g. pre-cooling) in the future, based on standardised conditions.

Increased core temperature (hyperthermia) has been associated with impaired neuromuscular performance; however, the mechanisms associated with these performance decrements and their potential synergies remain unclear. While the majority of research suggests that the observed fatigue is related to the central nervous system, the influence of changes in cerebral blood flow (CBF) and associated changes in cerebral alkalosis (estimated by end-tidal partial pressure of carbon dioxide; PETCO2) remains unexamined. In response to hyperthermia, humans hyperventilate as means of heat dissipation, resulting in a hypocapnia (reduced PETCO2) mediated decrease in CBF and consequently, cerebral alkalosis (increased cerebral pH). Previous research suggests that hyperventilation induces changes in neural excitability and synaptic transmission; however, it remains unclear if these changes are related to hypocapnia mediated decrease in CBF or decreased PETCO2 or both. The purpose of the proposed research program is to examine the influence of changes in CBF and cerebral alkalosis on neuromuscular function during passive heat stress. The research project will consist of 3 separate experimental trials: (a) poikilocapnic hyperthermia (increased core temperature; decrease CBF; decrease PETCO2), (b) isocapnic hyperthermia (increased core temperature; no change CBF; no change PETCO2) and (c) isocapnic hyperthermia + indomethacin (increased core temperature; decrease CBF; no change PETCO2). During each manipulation, neuromuscular function will be evaluated and compared to baseline (normothermic) conditions using a repeated measures design. It is hypothesized that changes in PETCO2 and therefore, changes in cerebral alkalosis will contribute to neuromuscular fatigue independent of changes in CBF or increases in core temperature.

The investigators goal is to monitor and quantify the differential physiologic and biomarker responses of controls to standardized exercise under thermoneutral and thermally challenged conditions and responses of exertional heat stroke (EHS) subjects under a thermal-challenged environment to develop unique bio-signature panels to predict those at risk for exertional heat illness (EHI) and guide return to duty following an episode of EHS.