Medicine and Health Sciences Commons^™

Assessment Of Iso Heart Rate Method To Estimate Metabolic Rate, Karl Williams

USF Tampa Graduate Theses and Dissertations

Thermal equilibrium is primarily maintained by the body’s ability to dissipate internal heat generated during muscle contraction. A number of methods have been used to quantify this thermal burden such as charts and observation of workplace activities and behavior, however these have varying levels of validity. ISO 8996 defines a more accurate method of metabolic rate estimation that uses heart rate and maximal work capacity (MWC); however this requires the use of laboratory settings and equipment that are rarely available in the field. Equations such as the ACSM metabolic equation for the total energy expenditure of walking, hereafter referred to …

Evaluation Of Two Methods To Estimate Wet Bulb Globe Temperature From Heat Index, Stephi Pofanl

USF Tampa Graduate Theses and Dissertations

The Wet bulb globe temperature (WBGT) is a common method to evaluate environmental factors that contribute to occupational heat stress. The Heat Index (HI) is readily available as an alternative to exposure methods. They both assess the most important contributors that are air temperature and humidity. WBGT also includes radiant heat and air motion. To account for radiant heat and/or air motion, some investigators have suggested adjustments to HI. The purpose of this study is to explore two methods to estimate the usefulness of WBGT from HI.

WBGT data were collected in a variety of locations that included direct sun …

The Effects Of Acute Hyperthermia On The Neurovascular Unit, Brooke Renee Shepley

Electronic Theses and Dissertations

With growing use for hyperthermia as a cardiovascular therapeutic, there is surprisingly little information regarding the acute effects it may have on the integrity of the neurovascular unit (NVU). Indeed, relying on animal data would suggest hyperthermia comparable to levels attained in thermal therapy will disrupt the blood- brain barrier (BBB) and damage the cerebral parenchymal cells. We sought to address the hypothesis that controlled passive hyperthermia is not sufficient to damage the NVU in healthy adults. Eleven young men (age 23 ± 3 years) underwent acute passive heating until +2°C or absolute esophageal temperature of 39.5°C. The presence of …

Does Time-Weighted Averaging For Wbgt And Metabolic Rate Work For Work-Recovery Cycles?, John W. Flach

USF Tampa Graduate Theses and Dissertations

Heat stress affects thousands of works annually by causing heat-related illnesses. Wet bulb globe temperature (WBGT) is a widely accepted metric to assess the environmental contributions to heat stress. WBGT-based occupational exposure limits (OELs) include the ACGIH TLVs and the NIOSH RELs. The OEL threshold is adjusted downward with increasing metabolic rate. Further, there is an OEL for acclimatized and non-acclimatized workers. An often-recommended intervention found within a heat stress management program is work-recovery cycles to manage exposure. To prescribe work-recovery cycles, the common practice is to use time-weighted averaging (TWA) for the WBGT and the metabolic rate. The purpose …

Heat Exposure And Adaptation Strategies Of Outdoor Informal Sector Workers In Urban Bulawayo - Zimbabwe, Bigboy Ngwenya

Theses: Doctorates and Masters

Ambient temperatures have risen over the past few decades and are expected to increase even further due to climate change impacts. Extreme temperatures, accompanied by high humidity levels, will exacerbate occupational heat stress, heat related illnesses and mortality amongst vulnerable groups, particularly among outdoor workers in developing countries in the tropics. In Bulawayo, Zimbabwe, a large portion of the population work outdoors in the informal sector as street vendors (hawkers) due to a lack of employment opportunities. These hawkers spend long hours in the sun or under makeshift sheds with poorly developed adaptation strategies, and no access to cooling systems …

The Effects Of Mild Dehydration On Cycling Performance In The Heat, Elika Hamer

Health, Human Performance and Recreation Undergraduate Honors Theses

Abstract

Introduction: Hypohydration exceeding 2% of body mass (bm), affected by heat and thirst level, leads to decreased athletic performance. Both physiological and psychological factors of dehydration have an impact on an athlete’s perceived performance. However, it is unclear whether the effects of psychological, physiological, or both have a negative impact on athletic performance caused by mild hypohydration. Purpose: The purpose of this study was to determine if mild hypohydration affects exercise performance in trained cyclists while blinding their hydration state. Methodology: Eleven competitive male cyclists participated in two blinded experimental trials, hypohydrated and euhydrated states by intra-venous infusions. The …

Evaluation Of The Effects Of Formaldehyde On Growth Parameters Of Broiler Chicks, Paula Johnson

Graduate Theses and Dissertations

Formaldehyde has been used as a disinfectant in poultry hatching cabinets to aid in controlling key pathogenic organisms, such as Salmonella and Escherichia coli (E.coli). There is some evidence that prolonged exposure of chicks to formaldehyde can reduce tracheal ciliary function and thus reasons to believe that exposure to formaldehyde, in the absence of pathogen challenge, may reduce chick vitality. It has been found that elevated temperatures during incubation may adversely affect body weights of broiler chicks, as well as post-hatch environmental heat stress on performance in poultry. Post-hatch environmental heat stress has been shown to impact performance in poultry. …

Analyzing Indoor And Outdoor Heat Index Measurements In Kitchens, Allison Welch

USF Tampa Graduate Theses and Dissertations

Occupationally induced heat-related illnesses (HRI) can play a huge part in the lives of employees working within outdoor kitchens. According to the National Institute for Occupational Safety and Health [NIOSH] (2016), “exposure to heat can result in injuries, disease, reduced productivity and death”. When working in outdoor environments, it is important to limit exposure time of direct sun or heat as well as to stay properly hydrated. One way to ensure limited occupational heat exposure is by measuring the Heat Index of the worker's environmental conditions.

The purpose of this study is to determine whether there was a difference between …

Effect Of Fluid Temperature And Volume On Thermoregulation In The Heat, Michelle M. Johannsen

Graduate Student Theses, Dissertations, & Professional Papers

The link between thermoregulation, hydration status, and exercise performance in hot humid environments is controversial. The purpose of this study was to evaluate the effects of volume and temperature of ingested fluid on hydration status, thermoregulation and exercise performance. Recreationally active males (N=11, 24.7±5.9 years; VO₂max=58.2±6.0 mL/kg/min) completed two 3-hour intermittent exercise trials in the heat (31^o WBGT=35.5°C with 50% humidity). Participants consumed either 1 mL/kg body weight (BW) of room temperature water (35.5°C; ROOM) or 0.5 mL/kg of an ice slurry mixture (~0°C; COLD) every ten minutes throughout the trials in a randomized crossover design. Subjects …

Influence Of Maternal Age On The Effects Of Organic Selenium In The Animal Model Daphnia Pulex, Jordan E. Roberts

All ETDs from UAB

As a necessary micronutrient, seleno-L-methionine (SeMet) exhibits a U-shaped dose-response with deficiency and toxicity leading to adverse health outcomes. Some studies suggest dietary selenium may offer protection against toxicity from other metals, but excessive dietary levels can also lead to toxicity. In addition, increased maternal age has been shown to increase the risk of adverse developmental outcomes. We hypothesize that older maternal age will increase susceptibility in offspring exposed to toxic concentrations of SeMet. The goal of this project was to evaluate the effects of SeMet treatment on lifespan and determine if the effects are altered by maternal age using …

Heat Stress Prevention Program For Workers In Demilitarization Protective Ensemble At Pueblo Chemical Agent-Destruction Pilot Plant Training Facility, Joseph Padayhag

Graduate Theses & Non-Theses

The Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) is being constructed to dispose of the entire stockpile of sulfur mustard contained in munitions stored at Pueblo Chemical Depot, Colorado. The PCAPP Training Facility provides courses on protective measures necessary for making entries into areas with hazardous concentrations of chemical warfare agents in air. Students are trained to work in Demilitarization Protective Ensemble (DPE), an encapsulating, impermeable, and positive pressure suit. The course includes wearing the suit and performing tasks to simulate work in PCAPP toxic areas.

Wearing DPE will increase the heat stress load for workers making entries. The PCAPP heatstress …

Effects Of Mild Hypohydration And Hyperthermia On Cognition And Mood In Obese And Non-Obese Females, Jenna Marie Burchfield

Graduate Theses and Dissertations

INTRODUCTION: Information regarding effects of hypohydration (HY) and hyperthermia (HT) on cognition, mood and development of symptoms is conflicting since the two conditions often confound each other. Further, although obese individuals may have physiological impairments during heat stress, whether psychological impairments occur with HY and HT is unknown. PURPOSE: To assess the independent and combined effects of mild HY and HT on cognition, mood, and the development of symptoms in obese and non-obese females. METHODS: Twenty-two healthy females (11 non-obese, 22±2y, 61±6kg, 25±4% body fat; 11 obese, 22±2y, 80±18kg, 44±5% body fat) volunteered in two randomized, repeated-measures trials, involving passive …

Heat Stress: A Risk Factor For Skin Carcinogenesis, Leslie Calapre

Theses: Doctorates and Masters

BACKGROUND: The incidence of skin cancer in Australia has increased rapidly in the last few decades. Ultraviolet radiation (UV) is a major risk factor for skin carcinogenesis. UV, particularly the UVB spectrum, causes formation of cyclobutane pyrimidine dimers (CPD) in cellular DNA. Persistent and incorrectly repaired CPDs lead to DNA mutations and consequently, formation of cutaneous lesions. Interestingly, recent epidemiological studies have shown a significant increase in skin cancer incidence in geographical locations with high environmental temperatures. Thus, heat stress may potentiate the effects of UV exposure and act as an additional risk factor for skin cancer. Previous studies …

An Appraisal Of Experiences Of Climate Change And Adaptive Response To Heat Stress By Farmers In Rural Ghana, Kwasi Frimpong

Theses: Doctorates and Masters

With the increase in average global temperatures, heat-related illnesses and deaths have unfolded as occupational and health issues. Periods of high to extreme temperatures are becoming more common and are a leading cause of weather-related deaths in many countries. In agricultural settings of African countries, heat stress is a major concern as many smallholder farmers work outdoors with limited access to cooling systems even in their resting and living environments. This study, conducted in the Bawku East part of Northern-East Ghana in 2013, examines, in the context of climate change, the trends and impacts of heat stress on smallholder farmers, …

Can The Usa National Weather Service Heat Index Substitute For Wet Bulb Globe Temperature For Heat Stress Exposure Assessment?, Ivory Iheanacho

USF Tampa Graduate Theses and Dissertations

Heat stress occurs when the body cannot adequately cool itself due to the combined contributions of metabolic heat, environmental factors and clothing. Heat stress found in the workplace puts employees at risk of developing heat-related illnesses, disorders and could be fatal. The wet bulb globe temperature (WBGT) index is the current method used to assess environmental contributions to heat stress in an occupational setting. The purpose of this thesis was to explore whether the National Weather Service's Heat Index (HI) could substitute for the WBGT Index during occupational heat stress exposure assessment. The possibility of using the HI for heat …

Oxidative Stress For An Acute Bout Of Bikram Yoga In Healthy, Trained Adults, Kimberly Anne Trocio

UNLV Theses, Dissertations, Professional Papers, and Capstones

BACKGROUND:Generation of free radicals resulting in oxidative damage has been linked to cellular damage, aging, and human disease. Many studies have reported that physical exercise can contribute to oxidative stress. Further, exercise in a hyperthermic environment can promote additional oxidative stress. It is important to consider that practices in yoga may be beneficial in reducing oxidative stress according to some studies. The compound effects of exercise and hyperthermic exposure are experienced in the practice of Bikram yoga, the original "hot" yoga. Because Bikram yoga and other hot exercise classes are an increasingly growing fitness trend, it is necessary to investigate …

Evaluation Of Heat Stress In Migrant Farmworkers, Stephen L. Mcqueen

Electronic Theses and Dissertations

The rate of heat-related fatalities in crop production workers is almost 20 times that of other industries. Heat stress was investigated in migrant tomato workers in July, 2012, using measurements of body temperature, heart rates, body weight loss, evaluation of the thermal environment, and survey data. Using occupational safety criteria, these workers were found to work in an environment that should require protective measures to prevent heat strain. Increases in body temperature, heart rate, and physiological strain correlated with heat exposure. One third of workers had body weight percentage losses that indicated dehydration. However, working in hot environments appears to …

Performance Assessment Of Predicted Heat Strain In High Heat Stress, Ronald Eugene Long

USF Tampa Graduate Theses and Dissertations

Heat stress is a common physical agent associated with many occupations. The most commonly used method of assessing heat stress exposure is an empirical method using the Wet Bulb Globe Temperature Index but his method is limited in its ability to parse out individual contributors to the heat stress. The International Organization for Standardization (ISO) published a rational model called Predicted Heat Strain (PHS) in 2004, and rational methods have the advantage of separating out the individual pathways for heat exchange. The objective of this research was a performance assessment of the current PHS model. This experimental design consisted of …

Heat Stress Evaluation Of Protective Clothing Ensembles, Amanda Lee Pease

USF Tampa Graduate Theses and Dissertations

Clothing directly affects the level of heat stress exposure. Useful measures to express the thermal characteristics are WBGT (wet bulb globe temperature) clothing adjustment factor (CAF) or apparent total evaporative resistance (R_e,T,_a). The CAF is assigned through laboratory wear trials following a heat stress protocol in which the air temperature and humidity are progressively increased until the participant clearly loses the ability to maintain thermal equilibrium. The critical condition is the point of thermal transition and from these conditions both the CAF and Re,T,a are computed. The first objective of this study is to compare the …

Industrial Heat Stress : Using Ice Slurry Ingestion As A Practical Approach To Reducing Heat Strain In Workers, Joseph E. Maté

Theses: Doctorates and Masters

Personnel working in industry can encounter hot and humid conditions where uncompensable heat loads are experienced; an inability to dissipate stored heat increases the risk of developing a heat illness. In order to minimise the incidence of heat illnesses, several heat stress reduction interventions have been developed which aim to allow for safe repeated bouts of exposure to high thermal heat loads. These vary from modification of the working environment, wearing of personal protective equipment designed to cool, heat stress indices and/or hydration regimens. Despite these interventions, personnel still experience heat stress related illnesses. Consequently, the overall aim of the …