View clinical trials related to Heat Stress Disorders.
Filter by:Allergic rhinitis (AR) currently affects ~25% of Canadians, and due to factors of climate change, this number is expected to increase over the coming decade. AR symptoms can significantly impact individuals' quality of life by compromising sleep, productivity, and social interactions. To alleviate AR symptoms, North Americans tend to rely on H1 antihistamine medications available over-the-counter (OTC) at most pharmacies. However, public health authorities currently suggest restraining all antihistamines during heat waves due to beliefs that M3 muscarinic receptor and H1 receptor antagonism, independent pharmacological mechanisms of H1 antihistamines, might suppress thermoregulatory responses to heat stress and increase individuals' susceptibility to heat-related illness/injury. To date, studies using supramaximal doses of antihistamines have demonstrated reductions in sweating, however these doses and administration routes are not the typical use case. Additional studies utilizing fexofenadine, a second-generation H1 antihistamine, have linked H1 receptor antagonism to reductions in skin blood flow, potentially impacting thermoregulation by reducing peripheral blood redistribution. Empirical evidence supporting OTC H1 antihistamines impacting thermoregulatory control at recommended doses is scarce. Thus, this study aims to systematically assess whether three common OTC H1 antihistamines, taken as prescribed, alter thermoregulatory responses during thermal stress.
The study explores a multi-component heat strain prevention program for older agricultural workers in response to climate change. It assesses hydration, rest breaks, reflective clothing, and shade provision. Utilizing a quasi-experimental design, it targets 120 elderly workers, evaluating core temperature, heart rate, and heat strain symptoms. The goal is to establish the program's effectiveness in safeguarding worker health and safety amidst increasing temperatures, offering evidence-based recommendations for this vulnerable group and potentially other occupations affected by climate change.
Workplaces rely on upper heat stress limits provided by the American Conference of Governmental Industrial Hygienists (ACGIH) to manage the health and safety of workers in hot environments. This is primarily achieved by interspersing work with rest periods, the length of which is dictated by environmental conditions and work intensity, to maintain core temperature at or below 38.0°C (equivalent to a 1°C increase in body core temperature above resting levels). However, these guidelines employ a "one size fits all" approach to exposure limits that does not consider individual variation between workers. Moreover, they fail to provide direction on the safe, initial stay times before these heat-mitigation controls should be employed (i.e., rest breaks) in conditions exceeding upper heat stress limits. While recent work has generated estimates of the initial stay times for young to older men before heat-mitigation controls are required for moderate-intensity work, this information is limited to a single work bout and does not consider a second work bout preceded by an extended rest period (e.g., lunch) or next day effects. This is a key consideration, as prolonged work in the heat has been shown to cause next-day impairments in heat dissipation in older men. Further, it remains unclear if the application of the prescribed ACGIH work-rest allocations thereafter would alleviate increases in core temperature for the duration of the work period (e.g., start of shift versus post-lunch period). This project will address these knowledge gaps by determining if refinements in initial stay times for moderate-intensity work (represents the average work effort of physically demanding occupations) in the heat (26°C wet-bulb globe temperature) may be required for young and older adults for i) a second work bout that is preceded by an extended rest period such as a lunch break, and ii) a work bout performed on the next day. This includes assessing the efficacy of the prescribed ACGIH work-rest allocations to mitigate increases in core temperature beyond safe limits (>38.0°C, equivalent to a >1°C increase in body core temperature above resting levels) during these work periods. Given the known sex-differences in heat loss that can modulate core temperature regulation during an exercise-heat stress, the investigators will conduct separate analysis to identify modulating effects of biological sex on the initial stay times and effectiveness of the work-rest allocation as a heat-alleviation control.
Exertional heat stroke (EHS) is the most serious form of heat-illness that can occur during sports and exercise. If not recognized and treated immediately mortality rate of EHS is high. Early recognition and initiation of cooling are paramount. If temperature is reduced to < 40°C within 30 minutes of symptom onset, most patients recover completely. There are several strategies for cooling in EHS, including cooling with rotating in ice water soaked towels which cover the body of a patient. The aim of this research is to investigate the effectiveness and safety of treatment of EHS with ice water soaked towels to lower body temperature.
The purpose of this research study is to better understand ways that women and men differ physiologically, cognitively, physically, and cellularly to better prescribe helpful interventions that will prevent injury and risk of conditions like exertional heat illnesses or heatstroke. The main questions this project aims to answer are: 1. What is the relative stress contributing to performance differences between women and men during intense exercise in extremely hot and humid environments in response to exertional heat stress? 2. What is the relative contribution of responses in adipose tissue, cardiovascular tissue, gut microbiota, and musculoskeletal tissue on heat tolerance in women (vs. men) to exertional heat stress? 3. What is the impact of adding an antioxidant juice consumption regime and will it assist in enhancing performance during an acute bout of exercise-heat stress before and after heat acclimation? Subjects enrolled and approved for participation will perform: 1. a heat acclimation protocol which includes the completion of 5 days of prescribed exercise-heat exposure 2. two separate acute exercise-heat exposures for the assessment of thermotolerance and the investigation of potential enhancements in thermoregulatory performance that may occur after the completion of a 5-day heat acclimation protocol 3. a subset of subjects enrolled and approved for participation who opt in to antioxidant berry supplement consumption will either consume the active or placebo product throughout their participation.
The aim of this initial investigational study is to compare the effect of desloratadine on the inflammatory responses to heat stress in firefighters exercising in their personal protective equipment.
Women are often understudied in thermal physiology research, leaving recommendations for Soldier safety and performance in hot conditions based largely on data collected in men. Female sex hormones estradiol and progesterone clearly have non-reproductive physiological effects, including influences on thermoregulatory and cardiovascular function. However, mechanisms of differing physiological adaptations to repeated heat exposure (i.e., heat acclimation) as a function of reproductive hormone status have yet to be investigated in a systematic way. Understanding possible sex differences in adaptation or mechanisms for adaptation during heat acclimation is important to ultimately optimize interventions to maximize soldier health and safety during training and deployment in the heat. Our goals in the present study are to evaluate physiological and biophysical responses to a standard heat acclimation protocol in a group of young, healthy men and women. Thirty individuals (n=10 males, n=10 women with a low hormonal status (i.e. early follicular phase), n=10 women with a high hormonal status (i.e. midluteal phase)) will complete 10 consecutive days of exercise (treadmill walking: 3.1 mph/2% grade) in the heat (40°C /40% relative humidity) up to 3hr per day. Changes in core temperature, heart rate, and sex hormones will be assessed to examine differences in thermoregulatory response to heat acclimation.
The arduous nature of military training and operations require personnel to encounter high heat load, e.g., during intense physical exertion, particularly in the heat. These conditions reduce operational effectiveness and expose personnel to a risk of incapacitation and death from exertional heat illness (EHI). The aim of this study is to examine traditional and novel risk factors that may increase thermal strain and EHI likelihood in military recruits undergoing strenuous physical exercise.
Patients with autonomic failure are characterized by disabling orthostatic hypotension (low blood pressure on standing), and at least half of them also have high blood pressure while lying down (supine hypertension). Exposure to heat, such as in hot environments, often worsens their orthostatic hypotension. The causes of this are not fully understood. The purpose of this study is to evaluate whether applying local heat over the abdomen of patients with autonomic failure and supine hypertension during the night would decrease their nocturnal high blood pressure while lying down. This will help us better understand the mechanisms underlying this phenomenon, and may be of use in the treatment of supine hypertension.