Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: DiLeo T[original query] |
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Comparison of estimated core body temperature measured with the BioHarness and rectal temperature under several heat stress conditions
Seo Y , DiLeo T , Powell JB , Kim JH , Roberge RJ , Coca A . J Occup Environ Hyg 2016 13 (8) 0 PURPOSE: Monitoring and measuring core body temperature is important to prevent or minimize physiological strain and cognitive dysfunction for workers such as first responders (e.g., firefighters) and military personnel. The purpose of this study is to compare estimated core body temperature (Tco-est), determined by heart rate (HR) data from a wearable chest strap physiology monitor, to standard rectal thermometry (Tre) under different conditions. METHODS: Tco-est and Tre measurements were obtained in thermoneutral and heat stress conditions (high temperature and relative humidity) during four different experiments including treadmill exercise, cycling exercise, passive heat stress, and treadmill exercise while wearing personal protective equipment (PPE). RESULTS: Overall, the mean Tco-est did not differ significantly from Tre across the four conditions. During exercise at low-moderate work rates under heat stress conditions, Tco-est was consistently higher than Tre at all-time points. Tco-est underestimated temperature compared to Tre at rest in heat stress conditions and at a low work rate under heat stress while wearing PPE. The mean differences between the two measurements ranged from -0.1+/-0.4 to 0.3+/-0.4 degrees C and Tco-est correlated well with HR (r = 0.795 - 0.849) and mean body temperature (r = 0.637 - 0.861). CONCLUSION: These results indicate that, the comparison of Tco-est to Tre may result in over- or under-estimation which could possibly lead to heat-related illness during monitoring in certain conditions. Modifications to the current algorithm should be considered to address such issues. |
Effect of wearing an N95 filtering facepiece respirator on superomedial orbital infrared indirect brain temperature measurements
DiLeo T , Roberge RJ , Kim JH . J Clin Monit Comput 2016 31 (1) 67-73 To determine any effect of wearing a filtering facepiece respirator on brain temperature. Subjects (n = 18) wore a filtering facepiece respirator (FFR) for 1 h at rest while undergoing infrared thermography measurements of the superomedial periobital region of the eye, a non-invasive indirect method of brain temperature measurements we termed the superomedial orbital infrared indirect brain temperature (SOIIBT) measurement. Temperature of the facial skin covered by the FFR, infrared temperature measurements of the tympanic membrane and superficial temporal artery region were concurrently measured, and subjective impressions of thermal comfort obtained simultaneously. The temperature of the skin under the FFR and subjective impressions of thermal discomfort both increased significantly. The mean tympanic membrane temperature did not increase, and the superficial temporal artery region temperature decreased significantly. The SOIIBT values did not change significantly, but subjects who switched from nasal to oronasal breathing during the study (n = 5) experienced a slight increase in the SOIIBT measurements. Wearing a FFR for 1 h at rest does not have a significant effect on brain temperatures, as evaluated by the SOIIBT measurements, but a change in the route of breathing may impact these measurements. These findings suggest that subjective impressions of thermal discomfort from wearing a FFR under the study conditions are more likely the result of local dermal sensations rather than brain warming. |
Baseline evaluation with a sweating thermal manikin of personal protective ensembles recommended for use in West Africa
Coca A , DiLeo T , Kim JH , Roberge R , Shaffer R . Disaster Med Public Health Prep 2015 9 (5) 536-42 OBJECTIVE: Experience with the use of personal protective equipment (PPE) ensembles by health care workers responding to the Ebola outbreak in the hot, humid conditions of West Africa has prompted reports of significant issues with heat stress that has resulted in shortened work periods. METHODS: A sweating thermal manikin was used to ascertain the time to achievement of a critical core temperature of 39 degrees C while wearing 4 different PPE ensembles similar to those recommended by the World Health Organization and Medecins Sans Frontieres (Doctors Without Borders) at 2 different ambient conditions (32 degrees C/92% relative humidity and 26 degrees C/80% relative humidity) compared with a control ensemble. RESULTS: PPE ensembles that utilized coveralls with moderate to high degrees of impermeability attained the critical core temperature in significantly shorter times than did other ensembles. Encapsulation of the head and neck region resulted in higher model-predicted subjective impressions of heat sensation. CONCLUSIONS: To maximize work capacity and to protect health care workers in the challenging ambient conditions of West Africa, consideration should be given to adjustment of work and rest schedules, improvement of PPE (e.g., using less impermeable and more breathable fabrics that provide the same protection), and the possible use of cooling devices worn simultaneously with PPE. |
Salivary and serum cortisol levels during recovery from intense exercise and prolonged, moderate exercise
Powell J , DiLeo T , Roberge R , Coca A , Kim JH . Biol Sport 2015 32 (2) 91-95 The aim of this study was to compare serum (SERc) and salivary cortisol (SALc) responses during recovery from two different exhaustive exercises to determine peak cortisol sampling time and the agreement between SERc and SALc levels. Twelve healthy men underwent a maximal treadmill graded exercise to exhaustion (MEx) and a prolonged, submaximal cycle exercise in the heat for 90 min (PEx) while SERc and SALc samples were taken in parallel at baseline, end of exercise, and 15 min intervals over one hour of recovery. MEx and PEx significantly increased SERc and SALc levels (p<0.01) while absolute SERc levels were approximately 7-10 folds higher than SALc. SERc and SALc showed highly positive correlation (R=0.667-0.910, p<0.05) at most sampling times and only a few individual values were out of 95% limit of agreement when analyzed by Bland-Altman plots. However, peak SERc levels (MEx: 784.0+/-147, PEx: 705.5+/-212.0 nmol · L-1) occurred at 15 min of recovery, whereas peak SALc levels (MEx: 102.7+/-46.4, PEx: 95.7+/-40.9 nmol· L-1) were achieved at the end of exercise in MEx and PEx. The recovery trend of SERc and SALc also differed following MEx and PEx. Activity of 11beta-hydroxysteroid dehydrogenase type 2 enzymes may be suppressed following MEx compared to PEx. In conclusion, sampling for peak SERc and SALc levels should take into account their evolution and clearance characteristics as well as type of exercise performed, whereas SALc appeared to be a more sensitive marker than SERc for the measurement of cortisol responses during exercise recovery. |
Effect of short-term heat acclimation training on kinetics of lactate removal following maximal exercise
DiLeo TD , Powell JB , Kang HK , Roberge RJ , Coca A , Kim JH . J Sports Med Phys Fitness 2014 56 70-8 AIM: Heat acclimation (HA) evokes numerous physiological adaptations, improves heat tolerance and has also been shown to enhance lactate (LA) responses during exercise, similar to that seen with endurance training. The purpose of this study was to examine whether HA improves the body's ability to remove LA during recovery following maximal exercise. METHODS: Ten healthy men completed two trials of maximal treadmill exercise (PRE- and POST-HA) separated by 5 days of HA. Each day of HA consisted of two 45 minute periods of cycling at ~50% VO2max separated by a 15min rest period in an environmental chamber (Tdb 45 degrees C, RH 20%). In PRE-/POST-HA trials, venous blood was collected during 60 minutes of recovery to determine LA concentrations and removal kinetics (A2: amplitude and y2: velocity constant) using bi-exponential curve fitting. RESULTS: Physiological adaptation to heat was significantly developed during HA, as evidenced by end-exercise Tre (DAY1 vs. 5) (38.89+/-0.56 vs. 38.66+/-0.44 degrees C), Tsk (38.07+/-.51 vs. 37.66+/-.48 degrees C),HR (175.0+/-9.9 vs. 165.0+/-18.5 beats.min-1), and sweat rate (1.24 +/-.26 vs. 1.47 +/-.27 L.min-1) (p<.05). However, there was no significant difference in either LA concentrations (LA0min: 8.78+/-1.08 vs. 8.69+/-1.23; LApeak: 10.97+/-1.77 vs. 10.95+/-1.46; and La60min; 2.88+/-.82 vs. 2.96+/-.93 mmol.L-1) or removal kinetics (A2: -13.05+/-7.05 vs -15.59+/-7.90 mmol.L-1 and y2: .02+/-.01 vs .03+/-.01 min-1). CONCLUSION: The present study concluded that, while effective in inducing thermo-physiological adaptations to heat stress, short-term HA does not improve the body's ability to remove LA following maximal exercise. Therefore, athletes and workers seeking faster LA recovery from intense physical activity may not benefit from short-term HA. |
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