View clinical trials related to Heat Stress Disorders.
Filter by:Three male and three female semi-professional athletes, ranging in age from 22 to 27, participated in a study that was done at Lund University in Sweden to examine their physiological responses. The temperature and relative humidity were adjusted at 40 degrees Celsius for hot, dry conditions and 31 degrees Celsius for hot, wet conditions, respectively. The participants were instructed to engage in physical activity on a treadmill within the chamber for 70 minutes, or until participants were able to continue their exercise without difficulty within the allotted period. Participants were instructed to walk (5 kph) and run (8 kph). Participants pulse rate, breathing rate, oxygen consumption, and subjective reactions were all recorded. On the basis of the Wet Bulb Globe Temperature (WBGT), a heat stress index, the American College of Sports Medicine has made certain suggestions. The technique used to determine the temperature on a Celsius scale took into account the influences of relative humidity, air temperature, wind, and direct sunlight radiation. The American College of Sports Medicine advises delaying athletic competition when the WBGT is above 28 degrees. In the climate control chamber, the trials were carried out in high-risk circumstances (28 degrees Celsius WBGT). According to the study's findings, exercise is influenced by weather, and as air temperature rises, so do the intensity of exertion and thermal feeling.
Military personnel are called upon to serve in hot, dry or humid climates, which places great demands on their ability to tolerate heat. Induced heat stress can impair performance and lead to pathologies. Faced with the challenges of global warming, this issue is becoming increasingly important in the practice of sport. While hyperthermia is known to impair endurance performance, the underlying thermophysiological responses and regulatory mechanisms during prolonged exercise remain poorly understood. The effects of hyperthermia on mental performance raise questions about the degradation of interoceptive capacities and the deleterious impact on behavioral regulation, an important component of thermal risk management in ultra-endurance exercise. What's more, despite the muscular and hydromineral consequences (rhabdomyolysis, renal failure, dehydration) of prolonged exercise, few data are available on recovery kinetics. A better understanding of the factors conditioning recovery quality could help limit the deleterious consequences of ultra-endurance exercise.
• This study investigates and compares the within and in-between variances of the body responses to different heat stressors in a controlled lab-setting. The participants will be exposed to different heat sources while a variety of physiological heat strain reactions such as heartrate, sweat rate, and core body temperature are recorded using on- and in-body devices. For the participant monitoring during the study, medical grade devices such as a certified ECG and a swallowable sensor-pill to continuously monitor the core body temperature will be applied. A one-for-all wearable device is additionally applied for physiological validation. Further, sweat will be collected to assess (i) the local sweat rate and (ii) the appearance of different heat stress associated molecular markers in this non-invasively collectable biofluid. As a secondary aim, a model will be developed that will enable to predict the different heat stress sources out of the heat strain measurements.
The incidence and severity of hot weather and extreme heat events (heat waves) is increasing. As such, there is an urgent need to develop heat-alleviation strategies that can provide targeted protection for older adults who are at an elevated risk for heat-induced illnesses or death due to impaired body temperature and cardiovascular regulation. While air-conditioning provides the most effective protection from extreme heat, it is inaccessible for many individuals and cannot be used during power outages (e.g., heat-related rolling blackouts). Immersion of the lower limbs in cold water and/or the application of cold towels to the neck have been recommended as simple and sustainable alternatives to air-conditioning. However, empirical data to support the efficacy of these interventions for mitigating physiological strain and discomfort in older adults is lacking. To address this knowledge gap, this randomized crossover trial will evaluate the effect of lower limb immersion with and without application of cold towels to the neck on body core temperature, cardiovascular strain and autonomic function, dehydration, and thermal comfort in adults aged 65-85 years exposed to simulated heat wave conditions (38°C, 35% relative humidity) for 6 hours.
Repeated exposure to heat in a laboratory setting (acclimation) elicits a range of adaptations, which reduce heat illness risk and increase work capacity in the heat. Traditional approaches to heat acclimation require daily heat exposures of 1 to 2 hours over ~7 to 10 consecutive days. Heat acclimation approaches which reduce the number of days to achieve acclimation may have utility. The primary purpose of the proposed research is to determine whether it is possible to achieve a similar degree of heat acclimation to that seen with a traditional longer-term heat acclimation approach by increasing the frequency of heat exposure, utilising multiple daily heat exposures over a smaller number of days. Secondary aims of the research are to examine whether heat acclimation provides cross-adaptation to a hypoxic stressor and whether heat acclimation improves aerobic fitness.
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 primary aim of this study is to compare putative 'chronic' EHI risk factors between a cohort who have suffered a history of EHI and a control cohort with no EHI history. The secondary aim is to examine the influence of these EHI risk factors on thermoregulation during a standard heat tolerance assessment.
The purpose of this study is to measure fatigue and indicators of acute kidney injury during consecutive days of work in a hot environment.
The primary purpose of the proposed study is to evaluate the effects of a topical sodium bicarbonate lotion (PR Lotion, AMP Human, Park City, UT) on measures of hydration status and fluid balance in humans when exposed to the heat while resting and during light/moderate aerobic exercise. A secondary purpose is to examine these same effects with two differing dosage patterns of the lotion. A tertiary purpose is to investigate the effect of an amino acid rehydration beverage in comparison to a placebo on measurements of hydration, subjective assessments of stress, and vestibular as well as musculoskeletal measures of fatigue for up to 24-hours after the completion of both passive and exertional heat stress within a dehydrated state.
Severe heat strain arising from intense physical work under climate conditions that does not allow sufficient heat dissipation may lead to heat stroke. This severe conditions is hypothesized to be secondary to increased gut permeability and leakage of bacterial toxins across the gut membrane, stimulating a systematic inflammatory response and associated organ injury. Repeated such sub-clinical increases in gut permeability has been suggested to contribute to the high burden of chronic kidney disease among heat-stressed workers. Many marathon runners experience a transient increase in kidney injury biomarkers while running. Probiotics have been studied as a way to decrease gut permeability and reduce systemic inflammation in many settings, including in athletes . However, no study has measured renal outcomes among workers or athletes performing strenuous activity. This is of interest as it could test the hypothesis that gut-induced inflammation is a driver of kidney injury during heat stress, and could point to a possible intervention to add on to efforts to relieve heat strain. In the present study, recreational or professional runners will be randomized to take a probiotic supplement or placebo during a 4 week period preceding a strenuous physical exercise (minimum 21 km run). Urine samples will be taken before and after the run, and analyzed for markers of renal injury and inflammation.
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.