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Ian D Cameron - One of the best experts on this subject based on the ideXlab platform.
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Heat Exhaustion in the sun herald city to surf fun run
The Medical Journal of Australia, 1994Co-Authors: David Lyle, Peter R Lewis, David Richards, Rowland Richards, Adrian Bauman, John R Sutton, Ian D CameronAbstract:OBJECTIVE: To investigate the relationship between motivational factors and physical and biological causes of Heat Exhaustion in fun run entrants. DESIGN AND SETTING: Case-control study, The Sun-Herald City to Surf fun runs in Sydney in 1991 and 1992. PARTICIPANTS: There were 63,732 race entrants who completed the run and received a finishing time; 79 runners with Heat Exhaustion and 310 age, sex and performance matched controls were enrolled in the study. MAIN OUTCOME MEASURE: A diagnosis of Heat Exhaustion was made if a runner collapsed and, when first receiving medical care, had a rectal temperature of 38 degrees C or higher. RESULTS: Two readily identifiable groups of runners were at high risk of Heat Exhaustion--accomplished non-elite (preferred) runners and runners of good ability (Group A). The attack rate was highest among accomplished non-elite runners, but a combination of a relatively high rate and the large number of entrants in Group A runners accounted for most cases. Four major risk factors for Heat Exhaustion were identified: motivation to exceed previous performance targets; failure to drink fluids during the run; failure of trained runners to acclimatise for the race by training in the warmer parts of the day; and previous history of Heat Exhaustion. CONCLUSION: Information from this investigation will enable more effective targeting of educational prevention programs in The Sun-Herald City to Surf fun run and provide baseline data for monitoring the effectiveness of these programs to modify high risk behaviour by participants.
Graham P Bates - One of the best experts on this subject based on the ideXlab platform.
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the risk of Heat Exhaustion at a deep underground metalliferous mine in relation to surface temperatures
Occupational Medicine, 2000Co-Authors: A M Donoghue, Graham P BatesAbstract:The risk of Heat Exhaustion at a deep underground metalliferous mine was assessed in relation to thermal conditions prevailing on the surface. For each day of a 1-year prospective case series of Heat Exhaustion, surface 24-h mean wet and dry bulb temperatures were recorded. From this data, 24-h mean wet bulb globe temperatures were derived using certain assumptions. The three surface temperature variables were significantly higher on those days on which Heat Exhaustion occurred, compared to those days on which it did not occur (P < 0.001). The relative risk of Heat Exhaustion on days when the 24-h mean wet bulb globe temperature was in the range 26.0-28.0°C was 4.82 (95% confidence interval 2.12-10.96). Surface temperature data could be used at this mine to warn miners about the risk of Heat Exhaustion.
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the risk of Heat Exhaustion at a deep underground metalliferous mine in relation to body mass index and predicted vo2max
Occupational Medicine, 2000Co-Authors: A M Donoghue, Graham P BatesAbstract:The risk of Heat Exhaustion at a deep underground metalliferous mine was assessed in relation to the body-mass index (BMI) and predicted maximal oxygen uptake (Vo2max) of miners, using case-control methodology. Sixty-five cases of acute Heat Exhaustion and 119 controls were studied. Heat Exhaustion cases had a significantly higher BMI than controls (P=0.006). The odds ratios increased with BMI. For a BMI of 32.00-36.99, compared to a BMI of less than 27.00 the odds ratio was 3.63 (95% confidence interval, 1.42-9.36). Vo2max was not significantly lower in cases than controls. The odds ratios for Heat Exhaustion increased with decreasing Vo2max, but not significantly. The sample size provided 80% power of detecting an odds ratio of 2.5 or greater. Deep underground miners should be advised to maintain a BMI of 24-27. Selection of miners on the basis of BMI should not be used as an alternative to satisfactory engineering controls such as ventilation and refrigeration.
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Heat Exhaustion in a deep underground metalliferous mine
Occupational and Environmental Medicine, 2000Co-Authors: Michael A Donoghue, Murray J Sinclair, Graham P BatesAbstract:OBJECTIVES To examine the incidence, clinical state, personal risk factors, haematology, and biochemistry of Heat Exhaustion occurring at a deep underground metalliferous mine. To describe the underground thermal conditions associated with the occurrence of Heat Exhaustion. METHODS A 1 year prospective case series of acute Heat Exhaustion was undertaken. A history was obtained with a structured questionnaire. Pulse rate, blood pressure, tympanic temperature, and specific gravity of urine were measured before treatment. Venous blood was analysed for haematological and biochemical variables, during the acute presentation and after recovery. Body mass index (BMI) and maximum O 2 consumption (V˙o 2 max) were measured after recovery. Psychrometric wet bulb temperature, dry bulb temperature, and air velocity were measured at the underground sites where Heat Exhaustion had occurred. Air cooling power and psychrometric wet bulb globe temperature were derived from these data. RESULTS 106 Cases were studied. The incidence of Heat Exhaustion during the year was 43.0 cases / million man-hours. In February it was 147 cases / million man-hours. The incidence rate ratio for mines operating below 1200 m compared with those operating above 1200 m was 3.17. Mean estimated fluid intake was 0.64 l/h (SD 0.29, range 0.08–1.50). The following data were increased in acute presentation compared with recovery (p value, % of acute cases above the normal clinical range): neutrophils (p 2 (SD 49, range 33–290) Mean psychrometric wet bulb globe temperature was 31.5°C (SD 2.0, range 25.2–35.3). Few cases ( 1.56 m/s, air cooling power >248 W/m 2 , or psychrometric wet bulb globe temperature CONCLUSION Heat Exhaustion in underground miners is associated with dehydration, neutrophil leukocytosis, eosinopenia, metabolic acidosis, increased glucose and ferritin, and a mild rise in creatine kinase, aspartate transaminase, and lactate dehydrogenase. Heat cramps are associated with dehydration but not hyponatraemia. The incidence of Heat Exhaustion increases during summer and at depth. An increased fluid intake is required. Heat Exhaustion would be unlikely to occur if ventilation and refrigeration achieved air cooling power >250 W/m 2 at all underground work sites.
A M Donoghue - One of the best experts on this subject based on the ideXlab platform.
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type a lactic acidosis in occupational Heat Exhaustion
Occupational Medicine, 2003Co-Authors: A M DonoghueAbstract:BACKGROUND: This paper presents a further analysis of biochemical data collected during a 1 year prospective study of 106 cases of Heat Exhaustion at a deep underground metalliferous mine. RESULTS: Multiple regression analysis results indicate that the haemoglobin, serum creatinine and plasma lactate concentrations are statistically significant predictors of the anion gap. Together, they explain 65% of the variance in the anion gap (R(2) = 0.650). Spearman's rho correlation results also confirm that haemoglobin, creatinine and lactate are each statistically significantly correlated with the anion gap (P < 0.001). CONCLUSIONS: These results indicate that dehydration and lactate are important determinants of the metabolic acidosis previously observed in occupational Heat Exhaustion. It is likely that dehydration in these workers has resulted in poor muscle perfusion, anaerobic conditions and elevated lactate. This constitutes Type A lactic acidosis. Creatine kinase is not a statistically significant predictor of the anion gap in multiple regression (P = 0.956). Furthermore, the Spearman's rho correlation coefficient for creatine kinase versus the anion gap is weak (r(s) = 0.175) and is not statistically significant (P = 0.073). These results suggest that there was no rhabdomyolysis contributing to the metabolic acidosis.
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the risk of Heat Exhaustion at a deep underground metalliferous mine in relation to surface temperatures
Occupational Medicine, 2000Co-Authors: A M Donoghue, Graham P BatesAbstract:The risk of Heat Exhaustion at a deep underground metalliferous mine was assessed in relation to thermal conditions prevailing on the surface. For each day of a 1-year prospective case series of Heat Exhaustion, surface 24-h mean wet and dry bulb temperatures were recorded. From this data, 24-h mean wet bulb globe temperatures were derived using certain assumptions. The three surface temperature variables were significantly higher on those days on which Heat Exhaustion occurred, compared to those days on which it did not occur (P < 0.001). The relative risk of Heat Exhaustion on days when the 24-h mean wet bulb globe temperature was in the range 26.0-28.0°C was 4.82 (95% confidence interval 2.12-10.96). Surface temperature data could be used at this mine to warn miners about the risk of Heat Exhaustion.
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the risk of Heat Exhaustion at a deep underground metalliferous mine in relation to body mass index and predicted vo2max
Occupational Medicine, 2000Co-Authors: A M Donoghue, Graham P BatesAbstract:The risk of Heat Exhaustion at a deep underground metalliferous mine was assessed in relation to the body-mass index (BMI) and predicted maximal oxygen uptake (Vo2max) of miners, using case-control methodology. Sixty-five cases of acute Heat Exhaustion and 119 controls were studied. Heat Exhaustion cases had a significantly higher BMI than controls (P=0.006). The odds ratios increased with BMI. For a BMI of 32.00-36.99, compared to a BMI of less than 27.00 the odds ratio was 3.63 (95% confidence interval, 1.42-9.36). Vo2max was not significantly lower in cases than controls. The odds ratios for Heat Exhaustion increased with decreasing Vo2max, but not significantly. The sample size provided 80% power of detecting an odds ratio of 2.5 or greater. Deep underground miners should be advised to maintain a BMI of 24-27. Selection of miners on the basis of BMI should not be used as an alternative to satisfactory engineering controls such as ventilation and refrigeration.
Sineng Chia - One of the best experts on this subject based on the ideXlab platform.
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prognosis of adult men with Heat Exhaustion with regard to postural stability and neurobehavioral effects a 6 month follow up study
Neurotoxicology and Teratology, 2003Co-Authors: Sineng ChiaAbstract:Abstract The medical complications of Heat disorders, including hematological, cardiovascular and renal damage, have been well documented. However, very little has been written on its neurological complications. In an earlier study, we reported that men with Heat Exhaustion, studied 2 weeks after the acute episode, had significantly more symptoms of neurasthenia, poorer performance in short-term memory and slower reaction time. The cases (as a group) had significantly poorer postural stability. The objective of this study was to assess the prognosis of men with Heat Exhaustion with regard to postural stability and neurobehavioral functions 1 2 , 3 and 6 months after the acute episode. The study is prospective in design and spans a 2-year period. All soldiers who were diagnosed to have Heat Exhaustion (cases) from 1 March 1998 were included in the study. For each case, a healthy soldier (matched for age, ethnicity, years of education and military vocation) was recruited to serve as control. Each subject had a neurobehavioral assessment by using the Swedish Performance Evaluation System (SPES), a computerized test battery. The postural stability of the subjects was assessed using a computerized postural sway system. Each subject took the test 2 weeks after the acute episode and repeated the test 3 and 6 months later for duration of 2 years. We report here the findings of 21 Heat Exhaustion cases and 18 controls, which completed all the three tests (i.e. done 2 weeks after the acute episode and 3 and 6 months later). Significant differences were only detected in some of the neurobehavioral and neurophysiological parameters between the cases and the control for first two tests but not the third test. The prognosis of adult with Heat Exhaustion is good. There were no significant differences in neurobehavioral tests and postural stability among the cases and controls 6 1 2 months after the episode.
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postural stability and neurobehavioural effects of Heat Exhaustion among adult men
Neurotoxicology and Teratology, 2001Co-Authors: Sineng ChiaAbstract:Abstract The medical complications of Heat disorders, including haematological, cardiovascular and renal damage, have been well documented. However, very little has been written on its neurological complications. The objective of this study was to assess the effects of Heat Exhaustion on postural stability and neurobehavioral functions of men. The study is prospective in design and spans a 3-year period. All soldiers who were diagnosed to have Heat Exhaustion (cases) from 1 March 1998 to 31 August 1998 were included in the study. For each case, a healthy soldier (matched for age, ethnicity, years of education and military vocation) was recruited to serve as control. Each subject had a neurobehavioral assessment by using the Swedish Performance Evaluation System (SPES), a computerized test battery. The postural stability of the subjects was assessed using a computerized postural sway system. Findings for 37 Heat Exhaustion cases and 37 controls revealed that cases had a significantly higher prevalence of neurasthenia symptoms compared to the controls. There were significant (small) differences between the cases and controls in the neurobehavioral tests of choice reaction time, digit span and some parts of colour word stress and logical series measures. Postural stability in the cases was significantly poorer when in the “eyes-closed” condition, compared with the controls. Men with Heat Exhaustion, studied 2 weeks after the acute episode, had significantly more symptoms of neurasthenia, poorer performance in short-term memory and slower reaction time. The cases (as a group) had significantly poorer postural stability.
David Lyle - One of the best experts on this subject based on the ideXlab platform.
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Heat Exhaustion in the sun herald city to surf fun run
The Medical Journal of Australia, 1994Co-Authors: David Lyle, Peter R Lewis, David Richards, Rowland Richards, Adrian Bauman, John R Sutton, Ian D CameronAbstract:OBJECTIVE: To investigate the relationship between motivational factors and physical and biological causes of Heat Exhaustion in fun run entrants. DESIGN AND SETTING: Case-control study, The Sun-Herald City to Surf fun runs in Sydney in 1991 and 1992. PARTICIPANTS: There were 63,732 race entrants who completed the run and received a finishing time; 79 runners with Heat Exhaustion and 310 age, sex and performance matched controls were enrolled in the study. MAIN OUTCOME MEASURE: A diagnosis of Heat Exhaustion was made if a runner collapsed and, when first receiving medical care, had a rectal temperature of 38 degrees C or higher. RESULTS: Two readily identifiable groups of runners were at high risk of Heat Exhaustion--accomplished non-elite (preferred) runners and runners of good ability (Group A). The attack rate was highest among accomplished non-elite runners, but a combination of a relatively high rate and the large number of entrants in Group A runners accounted for most cases. Four major risk factors for Heat Exhaustion were identified: motivation to exceed previous performance targets; failure to drink fluids during the run; failure of trained runners to acclimatise for the race by training in the warmer parts of the day; and previous history of Heat Exhaustion. CONCLUSION: Information from this investigation will enable more effective targeting of educational prevention programs in The Sun-Herald City to Surf fun run and provide baseline data for monitoring the effectiveness of these programs to modify high risk behaviour by participants.
