Renal, metabolic, and circulatory responses to heat and exercise. Studies in military recruits during summer training, with implications for acute renal failure.
TL;DR: The effect of summer training exercises on the urinary sediment, renal excretion of heme pigm... is studied in military recruits during summer basic training.
About: This article is published in Annals of Internal Medicine.The article was published on 1970-08-01. It has received 102 citations till now. The article focuses on the topics: Kidney.
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TL;DR: An explanatory framework is proposed to enhance consideration of how climate change effects may operate and to encourage debate about this important aspect of the health impacts of climate change, to assist in developing public health policy, practice and research.
Abstract: Different aspects of climate change may affect mental health through direct and indirect pathways, leading to serious mental health problems, possibly including increased suicide mortality. We prop ...
578 citations
Cites background from "Renal, metabolic, and circulatory r..."
...The primary cause of these effects is excessive core body temperature (Leithead and Lind 1964); dehydration due to inadequate fluid intake while sweating is also important (Schrier et al. 1970)....
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TL;DR: One result of climate change is a reduced work capacity in heat-exposed jobs and greater difficulty in achieving economic and social development in the countries affected by this somewhat neglected impact ofClimate change.
Abstract: Background: Global climate change is already increasing the average temperature and direct heat exposure in many places around the world. Objectives: To assess the potential impact on occupational health and work capacity for people exposed at work to increasing heat due to climate change. Design: A brief review of basic thermal physiology mechanisms, occupational heat exposure guidelines and heat exposure changes in selected cities. Results: In countries with very hot seasons, workers are already affected by working environments hotter than that with which human physiological mechanisms can cope. To protect workers from excessive heat, a number of heat exposure indices have been developed. One that is commonly used in occupational health is the Wet Bulb Globe Temperature (WBGT). We use WBGT to illustrate assessing the proportion of a working hour during which a worker can sustain work and the proportion of that same working hour that (s)he needs to rest to cool the body down and maintain core body temperature below 38°C. Using this proportion a ‘work capacity’ estimate was calculated for selected heat exposure levels and work intensity levels. The work capacity rapidly reduces as the WBGT exceeds 26-30°C and this can be used to estimate the impact of increasing heat exposure as a result of climate change in tropical countries. Conclusions: One result of climate change is a reduced work capacity in heat-exposed jobs and greater difficulty in achieving economic and social development in the countries affected by this somewhat neglected impact of climate change. Keywords: climate change; work; heat; occupational health; productivity (Published: 11 November 2009) Citation: Global Health Action 2009. DOI: 10.3402/gha.v2i0.2047
566 citations
Cites background from "Renal, metabolic, and circulatory r..."
...The main factor underlying these effects is the increased core body temperature (13), but dehydration due to sweating and inadequate liquid intake is also of major importance (14)....
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...Symptomatic exhaustion and clinical diseases, particularly kidney disease (14), can be the result of excessive dehydration (9)....
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TL;DR: It is concluded that recruits in basic training with the sickle-cell trait have a substantially increased, age-dependent risk of exercise-related sudden death unexplained by any known preexisting cause.
Abstract: Case reports of sudden death during exertion have not established an association between the sickle-cell trait (hemoglobin AS) and exercise-related death To test this association, all deaths occurring among 2 million enlisted recruits during basic training in the US Armed Forces in 1977 to 1981 were classified from autopsy and clinical records as non-sudden deaths or as sudden deaths explained or unexplained by preexisting disease On the basis of known numbers of entering recruits (according to race, age, and sex) and published prevalence rates for hemoglobin AS (8 percent for black and 008 percent for nonblack recruits), death rates (per 100,000) were 322 for sudden unexplained deaths, 27 for sudden explained deaths, and 0 for non-sudden deaths among black recruits with hemoglobin AS, as compared with 12, 12, and 07 among black recruits without hemoglobin S and 07, 05, and 11 among nonblack recruits without hemoglobin S Among black recruits the relative risk of sudden unexplained death (hemoglobin AS vs non-hemoglobin S) was 276 (95 percent confidence interval, 9 to 100; P less than 0001), whereas among all recruits this risk was 398 (95 percent confidence interval, 17 to 90; P less than 0001) The relative risk of sudden unexplained death among all recruits increased with age (P less than 004), from 13 (ages 17 to 18) to 95 (ages 26 to 30) We conclude that recruits in basic training with the sickle-cell trait have a substantially increased, age-dependent risk of exercise-related sudden death unexplained by any known preexisting cause
385 citations
TL;DR: Immunoelectron microscopy has shown that this protein is localized selectively along surface membranes of the thick ascending loop of Henle, and the unique aggregation and gel formation of Tamm-Horsfall protein in response to increasing concentrations of electrolytes within physiologic ranges may influence the permeability characteristics of this nephron segment.
235 citations
TL;DR: The hypothesis that ischemia may be the mechanism of rhabdomyolysis with exercise in potassium depletion with respect to men who sustain environmental heat injury during intensive physical training in hot climates is supported.
Abstract: Rhabdomyolysis and myoglobinuria occur commonly in men who sustain environmental heat injury during intensive physical training in hot climates. These also occur in patients with potassium depletion. Since physical training in hot climates may be accompanied by serious losses of body potassium, the possibility was considered that performance of strenuous exercise when potassium deficient might enhance susceptibility to rhabdomyolysis. Potassium is released from contracting skeletal muscle fibers and its rising concentration in interstitial fluid is thought to dilate arterioles thereby mediating the normal rise of muscle blood flow during exercise. If potassium release from deficient muscle were subnormal, exercise would not be accompanied by sufficient muscle blood flow and rhabdomyolysis could occur by ischemia. This hypothesis was examined by comparing the effect of electrically stimulated exercise on muscle blood flow, potassium release, and histology of the intact gracilis muscle preparation in normal and potassium-depleted dogs. In normal dogs, muscle blood flow and potassium release rose sharply during exercise. In contrast, muscle blood flow and potassium release were markedly subnormal in depleted dogs despite brisk muscle contractions. Although minor histologic changes were sometimes observed in nonexercised potassium-depleted muscle, frank rhabdomyolysis occurred in each potassium-depleted animal after exercise. These findings support the hypothesis that ischemia may be the mechanism of rhabdomyolysis with exercise in potassium depletion.
226 citations
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TL;DR: Substantially substituted derivatives of hippuric acid which could be determined by appropriate coupling reactions were prepared and studied under conditions permitting the exact comparison of renal clearances with those of diodrast atnd hippuran.
Abstract: The efficiency with which diodrast (3, 5-diiodo-4-pyridone-1-acetic acid) and hippuran (oiodohippuric acid) are excreted by the renal tubules (1, 2) raises the question to what extent the organically-bound iodine in these molecules is responsible for the phenomenon of tubular excretion. Since suitable quantitative methods for the determination of unsubstituted compounds wvere not available, substituted derivatives of hippuric acid which could be determined by appropriate coupling reactions were prepared 2 and studied under conditions permitting the exact comparison of renal clearances with those of diodrast atnd hippuran. Methods of comparing clearances. When two substances, both of which are excreted by the tubules, are presented to the tubular excretory mechanism simultaneously, one substance may depress the tubular excretion of the other (2, 3).3 Consequently, in the absence of information to
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TL;DR: Having observed that ethanol leads to an elevation of serum uric acid concentration, the mechanisms of this effect are investigated and the amount of ethanol administered is indicated individually with the results observed in each patients.
Abstract: Traditionally, the drinking of large amounts of alcoholic beverages has been considered a common predisposing or precipitating cause of gout (1). Thus far, however, the possibility of a relationship between ethanol and urate metabolism does not seem to have been investigated. In an attempt to evaluate a possible effect of ethanol on uric acid metabolism, we have studied serum uric acid levels in patients intoxicated with ethanol. Having observed that ethanol leads to an elevation of serum uric acid concentration, we investigated the mechanisms of this effect. None had gout or any known cause of secondary hyperuricemia. Renal function was normal as judged by blood urea concentration and urinary sediment, there was no major hematological abnormality, and all except Subject 8 were afebrile. Although all except Subject 14 admitted considerable ethanol intake in the past, at the time of the study none showed clinical or laboratory evidence of liver disease except Subjects 1, 4, and 8, who had compensated hepatic cirrhosis. Subject 14 suffered from chronic idiopathic adrenal insufficiency and was being treated with desoxycorticosterone acetate (DOCA) at the time of the study. Studies in intoxicated patients. Sixteen patients were studied when admitted to the hospital acutely intoxicated with various alcoholic beverages. Venous blood was drawn for chemical determinations at the time of admission and at intervals thereafter. In each patient, the final serum uric acid concentration was compared with the initial value. The mean of the individual differences was calculated and its degree of significance tested by the t test (2). Metabolic Ward before, during, and after ethanol administration. The amount of ethanol administered is indicated individually with the results observed in each of these patients. A. Intravenous infusions. In three subjects, 13, 14, and 15, ethanol was given after an overnight fast as a continuous infusion of a 15 per cent by volume solution in isotonic saline. In Subject 15, this was preceded by a 2½-hour control period during which saline solution was administered. In Subject 13, a control test with isotonic saline solution alone was done on another day. B. Oral tests. After an overnight fast, Subjects 4, 16, 17, and 22 were studied for a 2½-hour control period during which water flavored with grapefruit juice was administered orally to compensate for urinary water losses. Thereafter, in addition to the water, the patients were given ethanol in concentrations varying from 10 to 35 per cent by volume. …
280 citations