This study examined the effects of precooling via ice ingestion on female cycling performance in hot, humid conditions. Ten female endurance athletes, mean age (28 ± 6 y), height (167.6 ± 6.5 cm) and body-mass (68.0 ± 11.5 kg) participated in the study. Participants completed an 800 kJ cycle time-trial in hot, humid conditions (34.9 ± 0.3 °C, 49.8 ± 3.5% RH). This was preceded by the consumption of 7 g∙kg-1 of crushed ice (ICE) or water (CON). There was no difference in performance time (CON 3851 ± 449 s; ICE 3767 ± 465 s), oxygen consumption (CON 41.6 ± 7.0 ml∙kg∙min-1; ICE 42.4 ± 6.0 ml∙kg∙min-1) or respiratory exchange ratio (CON 0.88 ± 0.05; ICE 0.90 ± 0.06) between conditions (p > .05, d < 0.5). Core and skin temperature following the precooling period were lower in ICE (Tc 36.4 ± 0.4 °C; Tsk 31.6 ± 1.2 °C) compared with CON (Tc 37.1 ± 0.4 °C; Tsk 32.4 ± 0.7 °C) and remained lower until the 100 kJ mark of the cycle time-trial (p < .05, d > 1.0). Sweat onset occurred earlier in CON (228 ± 113 s) compared with ICE (411 ± 156 s) (p < .05, d = 1.63). Mean thermal sensation (CON 1.8 ± 2.0; ICE 1.2 ± 2.5, p < .05, d = 2.51), perceived exertion (CON 15.3 ± 2.9; ICE 14.9 ± 3.0, p < .05, d = 0.38) and perceived thirst (CON 5.6 ± 2.2; ICE 4.6 ± 2.4, p < .05, d = 0.98) were lower in ICE compared with CON. Crushed ice ingestion did not improve cycling performance in females, although perceptual responses were reduced.
Matthew Zimmermann, Grant Justin Landers and Karen Elizabeth Wallman
Sandra Fowkes Godek and Arthur R. Bartolozzi
Alexander S.D. Gamble, Jessica L. Bigg, Tyler F. Vermeulen, Stephanie M. Boville, Greg S. Eskedjian, Sebastian Jannas-Vela, Jamie Whitfield, Matthew S. Palmer and Lawrence L. Spriet
∼2% of their body mass (BM) through sweating ( Baker et al., 2007 ; Dougherty et al., 2006 ; Edwards et al., 2007 ; Linseman et al., 2014 ; McGregor et al., 1999 ; Owen et al., 2013 ; Palmer et al., 2017 ). The equipment worn by ice hockey players becomes problematic as sweat rates increase to
Anita M. Rivera-Brown and Roberto A. De Félix-Dávila
Adolescent judo athletes who train in tropical climates may be in a persistent state of dehydration because they frequently restrict fluids during daily training sessions to maintain or reduce their body weight and are not given enough opportunities to drink.
Determine the body hydration status of adolescent judo athletes before, immediately after, and 24 h after (24H) a training session and document sweat Na+ loss and symptoms of dehydration.
Body mass and urine color and specific gravity (USG) were measured before, after, and 24 h after a training session in a high-heat-stress environment (29.5 ± 1.0°C; 77.7 ± 6.1% RH) in 24 adolescent athletes. Sweat sodium loss was also determined. A comparison was made between mid-pubertal (MP) and late pubertal (LP) subjects.
The majority of the subjects started training with a significant level of dehydration. During the training session, MP subjects lost 1.3 ± 0.8% of their pretraining body mass whereas LP subjects lost 1.9 ± 0.5% (P < .05). Sweat sodium concentration was 44.5 ± 23.3 mmol/L. Fluid intake from a water fountain was minimal. Subjects reported symptoms of dehydration during the session, which in some cases persisted throughout the night and the next day. The 24H USG was 1.028 ± 0.004 and 1.027 ± 0.005 g/mL for MP and LP, respectively.
Adolescent judo athletes arrive to practice with a fluid deficit, do not drink enough during training, and experience symptoms of dehydration, which may compromise the quality of training and general well-being.
Erin L. McCleave, Katie M. Slattery, Rob Duffield, Philo U. Saunders, Avish P. Sharma, Stephen Crowcroft and Aaron J. Coutts
acclimation reduces thermal and cardiovascular strain during exercise, predominantly by reduced core temperature, increased plasma volume (PV), increased sweat rate, and earlier sweat onset. 3 The benefits of both heat and hypoxia can last for several weeks following exposure. 5 , 6 As heat and hypoxia have
Dawn M. Emerson, Toni M. Torres-McGehee, Susan W. Yeargin, Kyle Dolan and Kelcey K. deWeber
cooling. Average sweat rates during ice hockey practices vary across collegiate (0.8 L/hr), 3 elite juniors (1.5 and 1.8 L/hr), 1 , 4 and professional players (2.1 to 2.5 L/hr). 2 Further, goalies often have the highest practice sweat rates, ranging from 1.7 to 2.9 L/hr. 1 , 2 , 4 Moderate- to high
Samuel T. Tebeck, Jonathan D. Buckley, Clint R. Bellenger and Jamie Stanley
physiological adaptations associated with the heat-acclimated phenotype (ie,plasma volume [PV] expansion, earlier onset of sweat, increased sweat rate, increased skin blood flow, etc). In these studies, the HI ranged from 28 (30°C and 24% RH 17 ) to 61 (39.5°C and 60% RH 16 ), making it difficult to elucidate
Martin J. Barwood, Joe Kupusarevic and Stuart Goodall
and sweat rate were calculated. Performance times were not revealed until the postexperiment debrief. Statistical Analysis Mean (SD) were calculated for perceptual (TS, TC, and RPE); performance (B lac , TTE duration); thermal ( T skin , T rec , and f c ) spray variables (temperature and volume
Elizabeth M. Broad, Louise M. Burke, Greg R. Cox, Prue Heeley and Malcolm Riley
Fluid losses (measured by body weight changes) and voluntary fluid intakes were measured in elite basketball, netball, and soccer teams during typical summer and winter exercise sessions to determine fluid requirements and the degree of fluid replacement. Each subject was weighed in minimal clothing before and immediately after training, weights, and competition sessions; fluid intake, duration of exercise, temperature and humidity, and opportunity to drink were recorded. Sweat rates were greatest during competition sessions and significantly lower during weights sessions for all sports. Seasonal variation in dehydration (%DH) was not as great as may have been expected, particularly in sports played indoors. Factors influencing fluid replacement during exercise included provision of an individual water bottle, proximity to water bottles during sessions, encouragement to drink, rules of the game, duration and number of breaks or substitutions, and awareness of personal sweat rates. Guidelines for optimizing fluid intakes in these three sports are provided.
James M. Green, Phil A. Bishop, Ian H. Muir and Richard G. Lomax
Sweat lactate is at least partly derived from eccrine-gland metabolism. This study examined whether potential age-associated changes in sweat rate and skin blood flow influence sweat lactate. Six middle-aged (51.5 ± 3.8 years) and 6 younger (25.8 ± 1.5 years) men similar in VO2max, height, weight, percent body fat, and surface area completed constant-load (CON) cycling and interval-cycling (INT) trials. During each trial, sweat and blood were analyzed for lactate concentration at 15, 25, 35, 45, and 60 min. Sweat rates and estimated total lactate secretion were not significantly different (p > .05) between trials or groups. Blood-lactate concentrations were not significantly different between groups during CON but were significantly higher in younger men at 35 min and 45 min during INT. Sweat-lactate concentrations were not significantly different (p > .05) between groups during CON or INT. These results suggest that differences in eccrine-gland metabolism between young and middle-aged men are minimal.