Thursday-Abstracts

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