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Official Journal of the American College of Sports Medicine Mean Local Sweat Rate (mg/min/cm2) ± SD Drink 15 min 30 min 50 min 60 min 75 min 1.5ºC 0.20 ± 0.09 0.40 ± 0.11 0.53 ± 0.12 0.58 ± 0.14 0.69 ± 0.15 37ºC 0.23 ± 0.11 0.50 ± 0.17 0.61 ± 0.22 0.66 ± 0.24 0.72 ± 0.27 50ºC 0.29 ± 0.15 0.61 ± 0.18 0.74 ± 0.21 0.79 ± 0.22 0.78 ± 0.23 NG 50ºC 0.39 ± 0.23 0.65 ± 0.23 0.70 ± 0.23 0.71 ± 0.23 0.69 ± 0.24 NG 1.5ºC 0.27 ± 0.11 0.43 ± 0.15 0.49 ± 0.16 0.51 ± 0.15 0.57 ± 0.16 SW 50ºC 0.29 ± 0.17 0.50 ± 0.20 0.57 ± 0.24 0.60 ± 0.21 0.61 ± 0.21 SW 1.5ºC 0.36 ± 0.29 0.51 ± 0.24 0.62 ± 0.22 0.60 ± 0.24 0.60 ± 0.24 1493 Board #85 May 30, 3:30 PM - 5:00 PM sweat sodium Content: Concurrent Validity Of The horiba C-122 Tm and Wescor sweat Chek Tm analysers Eric DB Goulet, Tommy Dion, Audrey Asselin, Félix A. Savoie. University of Sherbrooke, Sherbrooke, QC, Canada. (No relationships reported) Currently, there exists two instruments that coaches and scientists can use to measure sweat sodium content under field conditions: the Horiba C-122TM and Wescor Sweat ChekTM. The former device (ion selective electrode technology) is low weight (~ 40g), low cost (~250 US$), pocket-sized and battery operated, whereas the latter (ion conductance technology) is semi portable (~1 kg), medium-priced (~2000 US$) and electrically operated. No studies have yet concurrently compared the validity of both instruments. This is an important issue, given the discrepant cost and physical and technical characteristics of the two devices. PurPOsE: To simultaneously determine the validity of the Horiba C-122TM and Wescor Sweat ChekTM against sweat sodium concentration values obtained with the flame photometry technique, which is the accepted reference method for the measurement of bodily sodium contents. METhOds: Sweat sodium samples (N=74) (patch collection technique, 5 x 7 cm non-adherent pads covered with highly-adhesive transparent dressings) were obtained from 26 exercising, heat-acclimatized soccer players, runners and triathletes, who each provided between 1 to 4 sweat samples from 1 to 4 different anatomical sites (forefront, thigh, upper back or forearm). rEsuLTs: Data were normally distributed (kolmogorov-smirnov test) and showed no sign of heteroscedasticity (standardized residuals vs. dependent variables). Sweat sodium concentration values obtained with the Horiba C-122TM and Wescor Sweat ChekTM correlated highly with those determined by flame photometry (Pearson product-moment correlation coefficient: r=0.98 vs. r=0.99; single measures (two-way random/absolute agreement) intra-class correlation coefficient: r=0.97 vs. r=0.98). In comparison to flame photometry, the Horiba C-122TM and Wescor Sweat ChekTM demonstrated similar biases (-3 mmol/L vs. 1 mmol/L), pure error of measurements (6 mmol/L vs. 5 mmol/L), standard error of the estimates (5.51 mmol/L vs. 3.53 mmol/L) and 95% Bland and Altman level of agreement confidence intervals (-3 ± 12 mmol/L vs. 1 ± 10 mmol/L). CONCLusION: These results indicate that both the Horiba C-122TM and Wescor Sweat ChekTM portable sodium analysers demonstrate a moderate level of agreement with the flame photometry technique. 1494 Board #86 May 30, 3:30 PM - 5:00 PM sweat Electrolyte Content and Fluid Loss in Elite Triathletes Riana R. Pryor, Amy B. Mausser, Douglas J. Casa, FACSM, J Luke Pryor, Lawrence E. Armstrong, FACSM, Evan C. Johnson, Brittanie M. Volk, Amy L. McKenzie, Luke N. Belval. University of Connecticut, Storrs, CT. (No relationships reported) Knowledge of 24-hour sodium and water turnover in trained triathletes during training in a warm environment is important for personalized nutrition, hydration and performance. PurPOsE: This study investigated triathlete urine and sodium 24-hour turnover during a period that included endurance exercise in a warm environment to determine if increases or decreases in consumption are necessary. METhOds: Thirty-three sponsored triathletes (19 men, 14 women; age: 37 ± 11 y, 32 ± 6 y; height: 181 ± 6 cm, 170 ± 4 cm; weight: 75.7 ± 7.6 kg, 60.1 ± 5.9 kg; best half Ironman time 4:16 ± 0:24 hr:min, 4:42 ± 0:20 hr:min, respectively) completed a 43.4 ± 3.8 minute treadmill run or friction resisted cycle ergometer ride (28.0 ± 0.5 ºC; 27.2 ± 4.9 % RH) at a self-selected intensity which was estimated to be similar to half Ironman triathlon race pace for the chosen modality. Whole body wash-down (WBW) determined sweat electrolyte content. Twenty-four hour urine and dietary records were collected to calculate sodium and water intake and losses. rEsuLTs: Both 24-hour water and sodium balance were similar between men and women. Vol. 45 No. 5 Supplement S289 Water (L·d-1 ) Sodium (mg) Male Female Male Female Total Intake 4.1 ± 1.9 3.0 ± 1.2 5081 ± 2277 3589 ± 1005* Exercise Intake 0.4 ± 0.4 0.3 ± 0.2 --- --- Sweat Output 1.4 ± 0.3 1.0 ± 0.3* 1423 ± 438 941 ± 476* Urine Output 2.8 ± 0.8 2.4 ± 0.7 4687 ± 1419 2791 ± 1162* Net Balance -0.2 ± 1.9 -0.5 ± 1.4 -1048 ± 2229 -161 ± 1435 Note. *Difference between sexes, p ≤ 0.05. Total water intake includes exercise intake. CONCLusION: Twenty-four hour sodium and water turnover were similar between trained male and female triathletes. When exercising in warm conditions, trained triathletes may need to slightly increase water replacement (5-17%) and moderately increase sodium supplementation (4-21%) to remain homeostatic. Supported by Timex, Inc., Middlebury, CT. 1495 Board #87 May 30, 3:30 PM - 5:00 PM Physiological Effects of Compression Garments during uncompensable heat stress Joshua T. Bautz, David Hostler, FACSM, Priya Khorana, Joe Suyama. Emergency Responder Human Performance Lab, University of Pittsburgh, Pittsburgh, PA. (No relationships reported) Thermal protective clothing (TPC) worn by firefighters protect users from flames but prevent evaporative cooling. Volume lost from sweating combined with heat stress and physical exertion places considerable strain on the cardiovascular system. Lower extremity compression garments (LECGs) have gained popularity with endurance athletes and are purported to improve performance by augmenting venous return. We hypothesized that the use of LECGs would therefore preserve intravascular volume leading to a lower heart rate (HR) while working in a hot environment. PurPOsE. Examine the effect of wearing LECGs under TPC on HR, core temperature (Tc), and markers of hydration during treadmill exercise. METhOds. Ten male subjects (mean age 27± 6 years, height 1.78± 0.092 m, mass 74.75± 6.974 kg, body fat 10.6± 4.22%, VO2 max 57.8± 9.29 mL/kg/min) completed the control (no LECG) and LECG experimental conditions in randomly assigned order. Protocols were separated by a minimum of three days. Subjects exercised for 90 minutes on a treadmill while wearing wilderness firefighter TPC and helmet in a heated room. Venous blood was drawn pre and post exercise to measure hemoglobin (Hgb), hematocrit (Hct), serum OSM (OSM), and serum CPK (CPK). Vital signs and perceptual measures of comfort and exertion were recorded every five minutes during the protocol. Paired samples t-tests were performed to compare the change in metrics between the two conditions. rEsuLTs. In comparing the LECG condition with the control condition, there were no differences in the change in HR (84±27 vs. 85±14 bpm, p=0.9), Hgb (0.49±0.66 vs. 0.33±1.11 g/dL, p=0.7), Hct (1.22±1.92 vs. 1.11±3.62%, p=0.9), or body mass (1.72±0.78 vs. 1.77±0.58 kg, p=0.7). There were no differences in distance walked (3.9±0.5 vs. 4.0±0.5 miles, p=0.2), exercise interval (88.6±3.5 vs. 88.4±3.6 minutes, p= 0.8), or perceptual measures of comfort or exertion. Additionally, there were no differences in Tc rise (1.8±0.6 vs. 1.9±0.5°C, p=0.394), OSM (1.67±6.34 vs. 6.22±11.39 mOsm/kg, p = 0.3), or CPK (22.2±30.2 vs. 29.8±19.4 IU/L, p = 0.5). Conclusions. LECG worn beneath TPC did not acutely alter the physiologic response to exertion in TPC. These data neither encourage nor discourage LECG use during uncompensable heat stress. 1496 Board #88 May 30, 3:30 PM - 5:00 PM Effects of different Types of Clothing on Thermoregulation and Microenvironments during simulated american Football Eric J. Jones, Nathan Frischmann, Mark D. Faries, Wesley Kephart. Stephen F. Austin State University, Nacogdoches, TX. (Sponsor: Thomas J. Pujol, FACSM) (No relationships reported) PurPOsE: This study assessed the effects of two different types of clothing on core temperature (Tc), skin temperature (Ts), and the microenvironments (ME) of collegeaged males during a simulated football game within hot environments. METhOds: Trained college-aged males (n = 10) participated in a series of 5-second ergometer sprints in a climate-controlled chamber (35°C, 55%RH). The sprint protocol was based on the average number and length of plays within NCCA Division I football games. Subjects performed two separate trials, each consisting of 85 minutes, separated by a 48-hour washout period. During trials, either cotton or channeled fabric clothing (CFC) was donned under protective football gear. Tc, Ts, and ME temperature and humidity was monitored throughout trials. rEsuLTs: Paired samples t-test revealed significant differences (p
<strong>Thursday</strong>, May 30, 2013 S290 Vol. 45 No. 5 Supplement CFC was 2.6±0.8 and 2.2±1.1 respectively (p=0.04). ME chest temperature changes for cotton and CFC were 3.7±1.05 and 3.0±0.91, respectively (p
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