, or sweat rate. These findings differ to previous studies reporting similar heat adaptations following approximately 2 weeks of heat training or heat training combined with LHTL. 2 , 8 The different findings may relate to factors including participant training status and environmental dose. Buchheit
Erin L. McCleave, Katie M. Slattery, Rob Duffield, Philo U. Saunders, Avish P. Sharma, Stephen Crowcroft and Aaron J. Coutts
Thomas Reeve, Ralph Gordon, Paul B. Laursen, Jason K.W. Lee and Christopher J. Tyler
, heart rate (HR), and core temperature to a similar extent as a moderate-intensity/low-volume protocol (∼35 min, 75% maximal oxygen uptake) suggesting that elevating the exercise intensity can reduce the duration required for heat adaptation. 8 The effect of these physiological adaptations on subsequent
Anita M. Rivera-Brown and José R. Quiñones-González
This study determined normative data for sweat rate (SR) and whole-body (WB) sweat sodium concentration [Na+] in athletes indigenous to a tropical climate, categorized by age, gender, and sport classification. We analyzed data from 556 athletes (386 adult and 170 young) in endurance (END), team/ball (TBA), and combat (COM) sports exercising in tropical environments (wet bulb globe temperature = 29.4 ± 2.1 °C). SR was calculated from change in body weight corrected for urine output and fluid/food intake. Sweat was collected using absorbent patches, and regional [Na+] was determined using an ion selective analyzer and normalized to WB sweat [Na+]. Data are expressed as mean ± SD. SR was higher in males compared with females in both young (24.2 ± 7.7 ml·kg−1·hr−1 vs. 16.7 ± 5.7 ml·kg−1·hr−1) and adult (22.8 ± 7.4 ml·kg−1·hr−1 vs. 18.6 ± 7.0 ml·kg−1·hr−1) athletes, in END sports in girls (END = 19.1 ± 6.0 ml·kg−1·hr−1; TBA = 14.6 ± 4.5 ml·kg−1·hr−1), and in adult males (END = 25.2 ± 6.3 ml·kg−1·hr−1; TBA = 19.1 ± 7.2 ml·kg−1·hr−1; COM = 18.4 ± 8.5 ml·kg−1·hr−1) and females (END = 23.5 ± 5.6 ml·kg−1·hr−1; TBA = 14.2 ± 5.2 ml·kg−1·hr−1; COM = 15.3 ± 5.2 ml·kg−1·hr−1); p < .05. WB sweat [Na+] was higher in adult athletes than in young athletes (43 ± 10 mmol/L vs. 40 ± 9 mmol/L, p < .05). These norms provide a reference range for low, low average, average high, and high SR and WB sweat [Na+], which serve as a guide for fluid replacement for athletes who live and train in the tropics.
Samuel T. Tebeck, Jonathan D. Buckley, Clint R. Bellenger and Jamie Stanley
RH. 13 Together, these data suggest an improvement in convective heat dissipation in humid compared with dry STHA. Limited research investigating heat adaptation on skeletal muscle metabolism exists, however muscle glycogen has been reported to be spared, 34 although there is limited evidence for
Gordon G. Sleivert
Wireless microtechnologies are rapidly emerging as useful tools for sport scientists to move their work out of the laboratory and into the field. The purpose of this report is to describe some of the practical aspects of using ingestible radiotelemetric temperature sensors in sport physiology. Information is also presented to demonstrate the utility of this technology in understanding individual differences in coping with environmental stress, optimizing heat adaptation, and fine-tuning competition strategy (pacing). Wireless core-temperature technology has already revolutionized field monitoring of elite athletes training and competing in extreme environments. These technologies are valuable tools for sport scientists to better understand the interaction between the physiology of exercise and the environment.
Shona L. Halson, Louise M. Burke and Jeni Pearce
Domestic and international travel represents a regular challenge to high-performance track-and-field athletes, particularly when associated with the pressure of competition or the need to support specialized training (e.g., altitude or heat adaptation). Jet lag is a challenge for transmeridian travelers, while fatigue and alterations to gastrointestinal comfort are associated with many types of long-haul travel. Planning food and fluid intake that is appropriate to the travel itinerary may help to reduce problems. Resynchronization of the body clock is achieved principally through manipulation of zeitgebers, such as light exposure; more investigation of the effects of melatonin, caffeine, and the timing/composition of meals will allow clearer guidelines for their contribution to be prepared. At the destination, the athlete, the team management, and catering providers each play a role in achieving eating practices that support optimal performance and success in achieving the goals of the trip. Although the athlete is ultimately responsible for his or her nutrition plan, best practice by all parties will include pretrip consideration of risks around the quality, quantity, availability, and hygiene standards of the local food supply and the organization of strategies to deal with general travel nutrition challenges as well as issues that are specific to the area or the special needs of the group. Management of buffet-style eating, destination-appropriate protocols around food/water and personal hygiene, and arrangement of special food needs including access to appropriate nutritional support between the traditional “3 meals a day” schedule should be part of the checklist.
Carl J. Petersen, Marc R. Portus, David B. Pyne, Brian T. Dawson, Matthew N. Cramer and Aaron D. Kellett
Cricketers are often required to play in hot/humid environments with little time for heat adaptation.
We examined the effect of a short 4-d hot/humid acclimation program on classical physiological indicators of heat acclimation.
Male club cricketers were randomly assigned into heat acclimation (ACC, n = 6) or control (CON, n = 6) groups, and 30 min treadmill trials (10 km/h, approx. 30 ± 1.0°C, approx. 65 ± 6% RH) were conducted at baseline and postacclimation. The ACC group completed four high intensity (30–45 min) acclimation sessions on consecutive days at approx. 30°C and approx. 60% RH using a cycle ergometer. The CON group completed matched cycle training in moderate conditions (approx. 20°C, approx. 60% RH). Physiological measures during each treadmill trial included heart rate; core and skin temperatures; sweat Na+, K+ and Cl– electrolyte concentrations; and sweat rate.
After the 4-d intervention, the ACC group had a moderate decrease of -11 (3 to -24 beats/min; mean and 90% CI) in the 30 min heart rate, and moderate to large reductions in electrolyte concentrations: Na+ -18% (–4 to -31%), K+ -15% (0 to -27%), Cl– -22% (-9 to -33%). Both ACC and CON groups had only trivial changes in core and skin temperatures and sweat rate. After the intervention, both groups perceived they were more comfortable exercising in the heat. The 4-d heat intervention had no detrimental effect on performance.
Four 30–45 min high intensity cycle sessions in hot/humid conditions elicited partial heat acclimation. For full heat acclimation a more intensive and extensive (and modality-specific) acclimation intervention is needed for cricket players.
Blake D. McLean, Kevin White, Christopher J. Gore and Justin Kemp
. As previous longitudinal data show that PV is suppressed during colder months, 11 this cold exposure may have contributed to lower PV. In addition to cold environments, positive heat adaptations can be blunted when heat training interventions are combined with living in hypoxia. 12 McCleave et
Amelia J. Carr, Philo U. Saunders, Laura A. Garvican-Lewis and Brent S. Vallance
-LHTL recovery period. Concurrently, 1 heat acclimation session was completed per week, consistent with published recommendations for inducing heat adaptations in athletes, especially when combined with heat acclimatization performed immediately prior to major competitions, 1 , 9 and therefore, 6 sessions in
Michael J. Zurawlew, Jessica A. Mee and Neil P. Walsh
, Moran D , Shapiro Y , Epstein Y . Changes in heart rate variability following acclimation to heat . J Basic Clin Physiol Pharmacol . 2001 ; 12 ( 1 ): 19 – 32 . PubMed ID: 11414505 doi:10.1007/s00421-014-2935-5 10.1515/JBCPP.2001.12.1.19 11414505 5. Taylor NS . Human heat adaptation