The Significance of Body Surface Area to Mass Ratio for Thermal Responses to a Standardized Exercise-Heat Stress Test.

PURPOSE: To evaluate the significance of body surface area-to-mass ratio (BSA/mass) on the heat-tolerance test (HTT) results. We hypothesized that individuals defined as heat tolerant (HT) would have on average higher BSA/mass compared to heat intolerant (HI) individuals. METHODS: A retrospective reanalysis of the HTT results of 517 soldiers (age: 18-38 yrs., M/F: 96/4%), who were tested by the Israel Defense Forces (IDF) HTT protocol. The criterion for heat tolerance in the current analysis was a rectal temperature (Tre) plateau during the second hour of the test. A logistic regression analysis to evaluate the predictive power of BSA/mass for heat intolerance was performed; the spline model was applied to show the odds for heat intolerance across BSA/mass. RESULTS: In men BSA/mass of HI individuals was lower than HT individuals (248 ± 19 vs. 262 ± 18 cm2/kg, p < 0.01, d = 0.76). In women a similar trend was noted but with no statistical significance between HT and HI groups. The odd ratio for heat intolerance for every unit increase in BSA/mass was 0.97 (CI 95% 0.95-0.99). The spline model plateaued above BSA/mass of 270 cm2/kg. CONCLUSIONS: The results imply that body-core temperature responses to a standard exercise-heat stress (fixed external work rate and climatic conditions) are influenced by BSA/mass. More specifically, lack of a steady state in Tre (indicating heat intolerance) was more likely to occur with every unit decrease in BSA/mass. These findings contribute to a better understanding of the role of body anthropometry in the response to a standard exercise-heat task that might have an implication on clinical decision-making about return to duty/play of soldiers, athletes and others who deemed to be identified as HI.

Stuttering in adolescence and the risk for dysglycemia in early adulthood.

AIMS: To investigate the association between stuttering during adolescence and the onset of dysglycemia (prediabetes or type 2 diabetes) in early adulthood among men and women. MATERIALS AND METHODS: This cohort study included Maccabi Health Services members assessed for mandatory military service at ages 16-19 during 1990-2019 and followed until 31 December 2020. Stuttering status was recorded in the baseline medical evaluation. Incident cases of dysglycemia were identified systematically using prediabetes and diabetes registries. Cox proportional hazard models were applied for men and women separately, adjusting for sociodemographics and medical status. RESULTS: The study cohort comprised 866,304 individuals (55% men; 0.21% with stuttering) followed for a total of 12,696,250 person-years. During the study period, 7.6% (n = 36,603) of men and 9.0% (n = 34,723) of women were diagnosed with dysglycemia. The mean ages at diagnosis were 34 and 32 years for men and women, respectively. Women with stuttering exhibited the highest dysglycemia incidence rate (102.3 per 10,000 person-years) compared with the other groups (61.4, 69.0, and 51.9 per 10,000 person-years for women without stuttering, men with stuttering, and men without stuttering, respectively). For both men and women, those with stuttering showed an increased risk of being diagnosed with dysglycemia compared with those without (adjusted hazard ratios 1.18 [1.01-1.38] and 1.61 [1.15-2.26], respectively). The associations persisted in extensive sub-analyses. CONCLUSIONS: Stuttering in adolescence is associated with a higher risk of dysglycemia in early adulthood for men and women. Screening and targeted prevention in this population, especially women, may be beneficial.

Practicing Emergency Medicine in the Metaverse: A Novel Mixed Reality Casualty Care Training Platform.

BACKGROUND: Current casualty care training modalities present several challenges, including limited simulation facilities, instructor dependence, lack of standardization, documentation of trainees' performance and training personalization. The study presents the design, development and preliminary evaluation of a novel hybrid training platform to address these challenges. METHODS: A mixed reality platform was chosen and developed to address field operators' requirements. The platform is easy to operate and can be set up by laypeople within 20-min in multiple environments. Individual-level training documentation is generated autonomously following each session, evaluating 30 aspects of performance. From this, a unique aggregated dataset emerges as a substrate for executives' dashboards and intelligent planning of future sessions. RESULTS: An evaluation process took part using simulator-based training in different stages along the project using a questionnaire (Likert-scale based). Fifty military physicians took part in an identical head injury scenario requiring airway management by endotracheal intubation and were immediately surveyed. CONCLUSION: TrauMR is an agile hybrid training that harbors the potential to address many of the emerging challenges of training for prehospital care in combat and civilian environments.

Heat Intolerance, Body Size, and Return to Duty.

BACKGROUND: Exertional heatstroke affects athletes and soldiers and can lead to temporary heat intolerance. The heat tolerance test (HTT) was developed to assist in the return-to-duty decisions of military personnel. Although there are several possible causes for heat intolerance, a soldier who fails the test is prevented from returning to serve in a front-line combat unit, regardless of the underlying reason.CASE REPORT: A 19-yr-old special infantry male soldier with unremarkable medical history collapsed during an afternoon hand-to-hand combat training session in the gym. The medic on site promptly initiated inefficient tap water cooling and measured a rectal temperature of 38.7 °C; he returned to duty the same evening. A few weeks later, after intensive physical training, he experienced exhaustion during a stretcher-carrying foot march. He was referred by the unit's physician, who suspected a condition of heat intolerance, to an HTT. The soldier underwent two HTTs, which were found to be positive. Consequently, he was discharged from serving in his infantry unit. No congenital or functional underlying causes could explain the diagnosis of heat intolerance.DISCUSSION: We discuss the possibility that the only explaining cause for the two positive HTTs was the soldier's anthropometric measures, particularly the low body surface area to body weight ratio. We raise the question of whether this soldier could have been returned safely to duty.Rabotin A, Epstein Y, Ketko I. Heat intolerance, body size, and return to duty. Aerosp Med Hum Perform. 2023; 94(7):546-549.