[Heat intolerance].
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Heat Stress Disorders↗
Biomedical subjects
Y Epstein
Publications and source records attributed to Y Epstein.
Heat intolerance induced by antidepressants.
A case in which prescription medications induced heat intolerance which led to heat stroke is presented. A subject who suffered from depression and was treated with fluoxetine HCL (prozac) and lithium carbonate was engaged in mild intermittent work for 4 hours under hot/dry climatic conditions (Ta = 37 degrees C, rh = 15%). The subject lost consciousness, was hyperthermic and suffered from disseminated intravascular coagulation. A year later residual cerebellar symptoms were still evident and severe atrophy of the cerebellar tissue was demonstrated in a CT scan. It is suggested that drug-induced heat intolerance was the predisposing factor that reduced the patient ability to sustain exercise-heat stress, and under the favorable environmental circumstances led to excessive heat accumulation which ultimately caused heat stroke. This is the first description, to our knowledge, of heat intolerance of a patient treated by a combination of fluoxetine and lithium carbonate.
Antidepressive Agents↗
Chronic colchicine treatment does not impair glucose tolerance in familial Mediterranean fever patients.
OBJECTIVE: To investigate a long-term colchicine treatment in inhibiting normal release of insulin, in response to a glucose load. SETTING: The Heller Institute of Medical Research, Sheba Medical Center, Tel-Hashomer. PATIENTS: Thirty-one familial Mediterranean fever (FMF) patients, treated continuously with colchicine (1.0-2.0 mg.day-1) for 2-13 years. METHODS: A standard oral glucose tolerance test (OGTT) was performed to study the effect of long-term colchicine treatment on glucose-induced insulin response. An intravenous glucose tolerance test (IVGTT) was then performed on randomly chosen FMF patients (n = 9) and age-matched controls (n = 5). Glucose was administered 30 min after intravenous colchicine (2 mg) infusion. The sum of 1st- and 3rd-min insulin levels served as an index of early-phase insulin release. RESULTS: Based on the Office Guide to Diagnosis of Glucose Intolerance [13], one subject exhibited impaired glucose tolerance and two others had abnormal dynamics of glucose during the test but normal values at 120 min. Insulin values were normal in all participants. No significant differences were found in maximal glucose and insulin concentration, nor in the insulin release index between FMF colchicine-treated and healthy controls. CONCLUSIONS: Based on these findings, no impairment in glucose dynamics could be demonstrated in chronically colchicine treated patients, compared to untreated controls.
Administration, Oral↗
Heat-stroke-induced cerebellar atrophy: clinical course, CT and MRI findings.
We report the clinical course and CT and MRI findings in a case of heat-stroke-induced cerebellar atrophy. Although the cerebellar syndrome was severe concomitant with the onset of heat stroke, no abnormality was observed on brain CT in the first 2 weeks following the event. Cerebellar atrophy was first noted after 10 weeks on MRI; it was progressive during a 1-year follow-up.
Atrophy↗
Reported health concerns of Israeli high school students--differences by age and sex.
Health concerns of high school students in the 10th grade and again in the 12th grade were studied. The students filled out an anonymous questionnaire that included a list of 73 concerns. At both ages their main concerns were reportedly related to school. Concerns relating to army service ranked high particularly in the 12th grade, among both sexes. Concerns relating to sexual relations were frequent among boys at both ages, whereas concerns about mood and loneliness were more frequent among girls. Reports on physical concerns were frequently related to height among the younger boys and weight and diet among girls of both ages. Concerns were grouped into 6 domains. In each of them, except for sexuality, girls had more concerns. A significant decline in the number of concerns was noted from the first to the second survey, indicating a partial resolution of the issues central to adolescent development. Knowledge about concerns of adolescents may help health care providers in counseling and health education program planning.
Adaptation, Psychological↗
[Exertional heatstroke--diagnosis, treatment and prevention].
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Heat Stroke↗
A depressed workman with heatstroke.
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Antidepressive Agents↗
Insulin resistance in paraplegics--effect of one bout of acute exercise.
Insulin action was assessed in spinal cord injured (SCI) male individuals (n = 5) and compared to controls (C) (n = 5). Mean (+/-SD) age and body weight were 27.0 +/- 5.1 and 24.5 +/- 1.6 years and 68.6 +/- 3.2 and 76.6 +/- 5.0 kg for SCI and C group, respectively. Subjects performed physical activities 2-3 times/week on a non-competitive basis. Using the euglycemic clamp, metabolic clearance rate of glucose (g-MCR) was measured twice, one week apart; at a basal state and then 1 h after aerobic exercise. Exercise consisted of 60 min arm-crank at 20-25 watt and 60 rpm. During the hyperinsulinemic clamp, insulin concentration was 76 +/- 14 and 67 +/- 9 microU.ml-1, in SCI and in controls, respectively. At baseline, g-MCR was comparable in SCI and C individuals (8.1 +/- 2.4 and 8.0 +/- 2.1 ml.kg-1.min-1, respectively). After exercise, g-MCR remained at 7.9 +/- 2.0 and 8.5 +/- 2.6 ml.kg-1.min-1 in SCI and C, respectively. In spite of muscle atrophy, peripheral sensitivity to insulin was not impaired in paraplegics. No increase in insulin response to the exercise stimulus was seen in any of the groups. It may thus be suggested that the daily level of activity and the physical training performed by paraplegics, are sufficient to eliminate a state of insulin resistance, which often develops in extremely sedentary populations.
Adult↗
American College of Sports Medicine position stand. Heat and cold illnesses during distance running.
Many recreational and elite runners participate in distance races each year. When these events are conducted in hot or cold conditions, the risk of environmental illness increases. However, exertional hyperthermia, hypothermia, dehydration, and other related problems may be minimized with pre-event education and preparation. This position stand provides recommendations for the medical director and other race officials in the following areas: scheduling; organizing personnel, facilities, supplies, equipment, and communication; providing competitor education; measuring environmental stress; providing fluids; and avoiding potential legal liabilities. This document also describes the predisposing conditions, recognition, and treatment of the four most common environmental illnesses: heat exhaustion, heatstroke, hypothermia, and frostbite. The objectives of this position stand are: 1) To educate distance running event officials and participants about the most common forms of environmental illness including predisposing conditions, warning signs, susceptibility, and incidence reduction. 2) To advise race officials of their legal responsibilities and potential liability with regard to event safety and injury prevention. 3) To recommend that race officials consult local weather archives and plan events at times likely to be of low environmental stress to minimize detrimental effects on participants. 4) To encourage race officials to warn participants about environmental stress on race day and its implications for heat and cold illness. 5) To inform race officials of preventive actions that may reduce debilitation and environmental illness. 6) To describe the personnel, equipment, and supplies necessary to reduce and treat cases of collapse and environmental illness.
Frostbite↗
Energy expenditure variations in soldiers performing military activities under cold and hot climate conditions.
This study assessed the energetic status of soldiers exposed to intense physical activities in cold and warm weather. Thirty subjects participated in a two-phase study group A (n = 18) in the winter phase and group B (n = 12) in the summer phase. Energy expenditure (EE) was measured by the doubly labeled water technique; after a single, oral dosing of 2H(2)18O, daily urine samples were collected for 12 successive days. Energy intake (EI) was assessed from detailed food records analyzed by computerized food charts. Energy balance was calculated as the difference between EI and EE for each subject. Mean (+/- SE) daily EE was 4,281 +/- 170 and 3,937 +/- 159 kcal/day for the winter and summer groups, respectively. Daily EI was 2,792 +/- 124 kcal/day in group A and almost identical in group B. A negative energy balance of 1,422 +/- 163 kcal/day and 924 +/- 232 kcal/day (not significant) was calculated for groups A and B, respectively. Energy expenditure is primarily determined by the level of activity rather than by climate conditions; EI is insufficient to offset the high energy requirements under these conditions.
Adult↗
Concerns and risk behaviors and the association between them among high-school students in Jerusalem.
PURPOSE: To study the distribution, prevalence, determinants, and association between the health, social, and environmental concerns and risk behaviors of high school students in Jerusalem in order to provide a better basis for preventive and health promotion services. METHODS: 1078 tenth grade high school students, 15-16 years old answered an anonymous questionnaire including, perceived concerns and risk behaviors, (e.g., smoking, alcohol, drugs, and sexual activity). Concerns were grouped into six domains. RESULTS: The most frequently reported concerns related to school, weight, coping with aggression, fatigue, war, enlistment into army, and relationships with peers. Girls had more concerns in the domains of self-image, anxiety, and relationships with peers (p < .05). Adolescents with mothers who had less education had significantly more concerns in the domains of anxiety and relationships with peers and adults (p < .05). Forty-seven percent engaged in at least one risk behavior (boys 63% and girls 34%). The Guttman scalogram indicated the following sequence of risk behaviors: alcohol, cigarettes, sex, and drugs. There were statistically significant associations between concerns and risk behaviors in the domains of anxiety, sex, and relationships with adults and peers. CONCLUSION: Many adolescent concerns are universal, although the ranking and prevalence may vary based on different regional and population characteristics (e.g., in this population a high rate of concerns relating to aggression and war were identified). The results support the need to develop prevention and health promotion programs relating to the concerns and risk behaviors in the school and community, and individual counseling programs in primary care settings.
Adolescent↗
Validation and adjustment of the mathematical prediction model for human sweat rate responses to outdoor environmental conditions.
Under outdoor conditions this model was over estimating sweat loss response in shaded (low solar radiation) environments, and underestimating the response when solar radiation was high (open field areas). The present study was conducted in order to adjust the model to be applicable under outdoor environmental conditions. Four groups of fit acclimated subjects participated in the study. They were exposed to three climatic conditions (30 degrees, 65% rh; 31 degrees C, 40% rh; and 40 degrees C, 20% rh) and three levels of metabolic rate (100, 300 and 450 W) in shaded and sunny areas while wearing shorts, cotton fatigues (BDUs) or protective garments. The original predictive equation for sweat loss was adjusted for the outdoor conditions by evaluating separately the radiative heat exchange, short-wave absorption in the body and long-wave emission from the body to the atmosphere and integrating them in the required evaporation component (Ereq) of the model, as follows: Hr = 1.5SL0.6/I(T) (watt) H1 = 0.047Me.th/I(T) (watt), where SL is solar radiation (W.m-2), Me.th is the Stephan Boltzman constant, and I(T) is the effective clothing insulation coefficient. This adjustment revealed a high correlation between the measured and expected values of sweat loss (r = 0.99, p < 0.0001).
Adolescent↗
Validation and adjustment of the mathematical prediction model for human rectal temperature responses to outdoor environmental conditions.
Models to predict rectal temperature (Tre) have been based on indoor laboratory studies. The present study was conducted to validate and adjust a previously suggested model for outdoor environmental conditions. Four groups of young male volunteers were exposed to three different climatic conditions (30 degrees C, 65% rh; 31 degrees C, 41% rh; 40 degrees C, 20% rh). They were tested both in shaded and open field areas (radiation: 80 and 900 W.m-2, respectively) at different work loads (100, 300 and 450 watt). Exercise consisted of two bouts of 10 minutes rest and 50 minutes walking on a treadmill, at a constant speed (1.4 m.s-1) and different grades. The subjects were tested wearing cotton fatigues and protective garments. Their Tre and heart rate were monitored every 5 min and skin temperature every 15 min, oxygen uptake was measured towards the end of each bout of exercise; concomitantly, ambient temperature, relative humidity and solar load were monitored. We concluded that: (a) the corrected model to predict rectal temperature overestimates the actual measurements when applied outdoors; (b) radiative and convective heat exchanges should be considered separately when using the model outdoors; (c) radiative heat exchange should also be considered separately for short-wave radiation (solar radiation) and long-wave emission from the body to the atmosphere. Finally, an adjusted model to be used outdoors was suggested.
Adolescent↗
Follow-up study of anonymous ovum donors.
A follow-up study was conducted to determine the emotional and medical responses of anonymous ovum donors to participation in an ovum donation procedure. Medically, donors reported significant discomfort, particularly relating to bloating, immediately prior to retrieval and for a brief period following retrieval. However, donors indicated that these effects no longer persisted at the time of follow-up. They also mentioned how unusual and initially anxiety-arousing it was to be in charge of their own injections. Few donors reported serious adverse emotional responses; many reported positive emotional responses to participation. Donors felt proud of their contribution, talked about their participation with friends and relatives, would be willing to participate again and would recommend ovum donation to other women. However, since the sample included only 43% of the 74 women who donated, caution is necessary in generalizing from the results of our study.
Confidentiality↗
Predicting heart rate response to various metabolic rates, environments, and clothing.
A mathematical model that describes heart rate (HR) responses to different combinations of metabolic levels, climatic conditions, and clothing ensembles was developed. The database that served to construct the model consisted of 48 variations representing a wide range of environmental conditions, clothing ensembles, and metabolic rates. The model, which correlates highly with the observed values (r = 0.88, P < 0.0001), is based on physiological and environmental parameters: HR = 57.1 + 0.6HRi + [0.07M - 19.06 - 0.011(Emax - Ereq)] log t, where HRi is initial HR in beats per minute (at rest before the exposure), t is the time of exposure in minutes, M is the metabolic rate in watts, Ereq is the required sweat evaporation for thermal equilibrium in watts, and Emax is the maximal evaporative capacity of the environment in watts. The model's validity was tested by using two independent databases representing wide ranges of conditions; the correlation between measured and predicted values was found to be highly significant (r = 0.83, P < 0.001 and r = 0.77, P < 0.001, respectively). In summary, the present study suggests a valid predictive model for HR that overcomes some of the difficulties observed in other models.
Adult↗
Calculation of mean arterial pressure during exercise as a function of heart rate.
Mean arterial blood pressure (MAP) is a common characteristic of the cardiac cycle. Usually it is evaluated by assuming that the left ventricular ejection time (systole) constitutes a constant proportion of the cardiac cycle (i.e. 1/3), regardless of the heart rate (HR). However, elevation of HR during exercise results in a reduction of the duration of the ejection period and even a greater reduction of the ventricular filling period. Therefore, a constant diastole/systole proportion at various heart rates may be misleading. The purpose of this study was therefore to evaluate the accurate proportion of the systolic period from the cardiac cycle at different metabolic rates and calculate MAP accordingly. Twenty healthy subjects (age: 20-50 yr.) exercised at different work intensities on a cycle ergometer to elicit HR in the range of 55-180 bpm. During the ride the mitral and aortic flow velocity wave form were recorded by Doppler echocardiography; the mitral flow from the apical view and the aortic flow from the apical long axis view. Blood pressure was measured using a sphygmomanometer. The fraction of systole (St) from the heart cycle was related to HR and was described in mathematical terms as: St = 0.01exp(4.14-40.74/HR) MAP was then calculated from the diastolic blood pressure (dBP) and the pulse pressure (PP) adjusted for St as follows: MAP = dBP+St.PP; (mmHg) The use of the suggested model reduces errors in the evaluation of various cardiac parameters which are related to arterial pressure, such as peripheral resistance, especially under exercise-heat stress.
Adult↗
Glucose utilization in morbidly obese subjects before and after weight loss by gastric bypass operation.
OBJECTIVE: To investigate the effect of weight reduction induced by gastric bypass operation (GBO), on the peripheral resistance to insulin in extremely obese subjects. DESIGN: A three-stage euglycemic clamp was applied to assess the metabolic clearance rate of glucose (g-MCR) in lean controls and in obese subjects, prior to and 6-12 months post operation. SUBJECTS: Six obese subjects (four obese normoglycemics-ON and two obese non-insulin dependent diabetics-OD) before and after GBO and six healthy, lean controls (LC) were compared. MAIN OUTCOME MEASURES: Body mass index after GBO, metabolic clearance rate of glucose under increasing insulin concentrations. RESULTS: GBO resulted in a significant change in body mass index from a pre-operation value (mean +/- s.d.) of 45.0 +/- 8.5 to 30.4 +/- 5.9 kg m-2 and remained significantly greater than controls (23.3 +/- 2.3 kg m-2). Glucose MCR increased from a mean baseline value of 3.0 +/- 1.6 to 6.7 +/- 3.9 ml kg-1 min-1 at post GBO (P) (P < 0.02). Similar effects were obtained under the two higher insulin concentration. CONCLUSIONS: GBO resulted in a massive reduction in BMI, that still remained above normal controls. This could explain the effect of weight reduction to decrease, but not completely reverse, peripheral resistance to insulin associated with obesity.
Adolescent↗
Clinical significance of serum creatine phosphokinase activity levels following exercise.
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Creatine Kinase↗