Temperature of Ingested Water and Thermoregulation During Moderate-Intensity Exercise

Wimer, Gregory S.; Lamb, D. R.; Sherman, W. M.; Swanson, Scott C.

doi:10.1139/h97-031

Cited by 46 publications

(51 citation statements)

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“…Environmental conditions in the studies were also quite varied, from cool (25 °C) to extremely hot (40 °C), with humidity ranging from 28% to 70%. The four studies reporting a significant effect of beverage temperature on either T c or performance tended to use a greater exercise stimulus (>65% VO 2peak ) and warmer, more humid conditions (Lee, Shirreffs, & Maughan, 2008;Mundel et al, 2006;Szlyk et al, 1989;Wimer et al, 1997). Studies (Lee, Maughan, & Shirreffs, 2008;Lee & Shirreffs, 2007) conducted in relatively cool, low-humidity environments all failed to show a significant effect of beverage temperature on performance.…”

Section: Discussionmentioning

confidence: 95%

“…Other studies (Armstrong et al, 1985;Mundel et al, 2006;Szlyk et al, 1989) allowed participants to drink ad libitum, so differential hydration status may have been a confounder. Two studies (Lee & Shirreffs, 2007;Wimer et al, 1997) gave a large, single bolus (1 L and 10 ml/kg, respectively) at one point during exercise, which is not characteristic of race practice, when athletes are more likely to intermittently drink smaller fluid volumes. No study has used a protocol that controlled fluid ingestion per kilogram of body weight or used fluid replacement to maintain hydration for the participants as is recommended practice (American College of Sports Medicine, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…Lower thermal stress may help modify the rise in heart rate and cardiovascular strain observed with exercise in the heat. Skin temperature and blood flow seem to be reduced after consuming a cold fluid (Lee, Shirreffs, & Maughan, 2008;Lee & Shirreffs, 2007;Wimer et al, 1997), which would decrease heat dissipation, but overall heat-storage capacity seems to increase, evidenced by a more gradual evolution of T c .…”

Section: Discussionmentioning

confidence: 99%

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Influence of Beverage Temperature on Exercise Performance in the Heat: A Systematic Review

Burdon

O’Connor²,

Gifford³

et al. 2010

International Journal of Sport Nutrition and Exercise Metabolism

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Purpose: Increased core temperature (T c ), impaired cardiovascular function, and dehydration contribute to fatigue during prolonged exercise in the heat. Although many studies have examined mechanisms addressing these factors, few have investigated the effect of cold beverage temperature on thermoregulation and exercise performance in the heat. Methods: Citations from MEDLINE (Ovid), Sport Discus (EBSCOhost), AUSPORT and AusportMed (Informit), Web of Science, and SCOPUS were identified from the earliest record until September 2008 using the search terms drink temperature, beverage temperature, fluid temperature, water temperature, and cold fluid combined with body temperature and thermoregulation. To be included, studies needed to assess core or rectal temperature during exercise in moderate or hot environmental conditions. After quality rating was completed by two reviewers, the difference in mean T c and exercise performance was calculated. Results: Ten studies meeting search inclusion criteria were available for analysis. Three were excluded because sufficient detail or statistical data were not reported. A meta-analysis was not performed because the studies were deemed too different to group. Three of the remaining 7 studies found modulated T c with cold beverage consumption, and from the 4 that conducted exercise performance tests, performance improved by 10% with cold fluids. Conclusion: Cold fluid may attenuate T c rise and improve exercise performance in the heat; however, study findings are mixed. Research using well-trained athletes and fluid-ingestion protocols replicating competition scenarios is required. Potential sensory effects of cold fluid in maintaining motivation also need to be assessed as a mechanism underpinning improved performance.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Influence of Beverage Temperature on Exercise Performance in the Heat: A Systematic Review

Burdon

O’Connor²,

Gifford³

et al. 2010

International Journal of Sport Nutrition and Exercise Metabolism

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“…Some studies have examined the effect of the temperature of drinks consumed during exercise on core temperature and exercise performance (Lee et al 2008a, b;Lee and Shirreffs 2007;Mundel et al 2006;Wimer et al 1997). Few studies, however, have focused specifically on reducing core temperature (Lee et al 2008b;Mundel et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Thermoregulatory responses to ice-slush beverage ingestion and exercise in the heat

2010

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We compared the effects of an ice-slush beverage (ISB) and a cool liquid beverage (CLB) on cycling performance, changes in rectal temperature (T (re)) and stress responses in hot, humid conditions. Ten trained male cyclists/triathletes completed two exercise trials (75 min cycling at ~60% peak power output + 50 min seated recovery + 75% peak power output × 30 min performance trial) on separate occasions in 34°C, 60% relative humidity. During the recovery phase before the performance trial, the athletes consumed either the ISB (mean ± SD -0.8 ± 0.1°C) or the CLB (18.4 ± 0.5°C). Performance time was not significantly different after consuming the ISB compared with the CLB (29.42 ± 2.07 min for ISB vs. 29.98 ± 3.07 min for CLB, P = 0.263). T (re) (37.0 ± 0.3°C for ISB vs. 37.4 ± 0.2°C for CLB, P = 0.001) and physiological strain index (0.2 ± 0.6 for ISB vs. 1.1 ± 0.9 for CLB, P = 0.009) were lower at the end of recovery and before the performance trial after ingestion of the ISB compared with the CLB. Mean thermal sensation was lower (P < 0.001) during recovery with the ISB compared with the CLB. Changes in plasma volume and the concentrations of blood variables (i.e., glucose, lactate, electrolytes, cortisol and catecholamines) were similar between the two trials. In conclusion, ingestion of ISB did not significantly alter exercise performance even though it significantly reduced pre-exercise T(re) compared with CLB. Irrespective of exercise performance outcomes, ingestion of ISB during recovery from exercise in hot humid environments is a practical and effective method for cooling athletes following exercise in hot environments.

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“…The effectiveness of fluid replacement depends on a number of factors such as volume 23,53) and temperature 41,54) of the fluid ingested, the rate of gastric emptying from the stomach, the rate at which fluid is absorbed from the small intestine 55,56) and type of exercise being performed 57) . In addition, as thermal strain and dehydration increase, there is a decrease in the rate of gastric empting due to decreased stomach secretion and contraction 58) .…”

Section: Fluid Replacementmentioning

confidence: 99%

The Management of Heat Stress for the Firefighter: A Review of Work Conducted on Behalf of the Toronto Fire Service

McLellan

Selkirk

2006

Ind Health

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This report provides a summary of research conducted through a grant provided by the Workplace Safety Insurance Board of Ontario. The research was divided into two phases; first, to define safe work limits for firefighters wearing their protective clothing and working in warm environments; and, the second, to examine strategies to reduce the thermal burden and extend the operational effectiveness of the firefighter. For the first phase, subjects wore their protective ensemble and carried their self-contained breathing apparatus (SCBA) and performed very light, light, moderate or heavy work at 25°C, 30°C or 35°C. Thermal and evaporative resistance coefficients were obtained from thermal manikin testing that allowed the human physiological responses to be compared with modeled data. Predicted continuous work times were then generated using a heat strain model that established limits for increases in body temperature to 38.0°C, 38.5°C and 39.0°C. Three experiments were conducted for the second phase of the project. The first study revealed that replacing the duty uniform pants that are worn under the bunker pants with shorts reduced the thermal strain for activities that lasted longer than 60 min. The second study examined the importance of fluid replacement. The data revealed that fluid replacement equivalent to at least 65% of the sweat lost increased exposure time by 15% compared with no fluid replacement. The last experiment compared active and passive cooling. Both the use of a mister or forearm and hand submersion in cool water significantly increased exposure time compared with passive cooling that involved only removing most of the protective clothing. Forearm and hand submersion proved to be most effective and produced dramatic increases in exposure time that approximated 65% compared with the passive cooling procedure. When the condition of no fluid replacement and passive cooling was compared with fluid replacement and forearm and hand submersion, exposure times were effectively doubled with the latter condition. The heat stress wheel that was generated can be used by Commanders to determine safe work limits for their firefighters during activities that involve wearing their protective clothing and carrying their SCBA.

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Temperature of Ingested Water and Thermoregulation During Moderate-Intensity Exercise

Cited by 46 publications

References 0 publications

Influence of Beverage Temperature on Exercise Performance in the Heat: A Systematic Review

Influence of Beverage Temperature on Exercise Performance in the Heat: A Systematic Review

Thermoregulatory responses to ice-slush beverage ingestion and exercise in the heat

The Management of Heat Stress for the Firefighter: A Review of Work Conducted on Behalf of the Toronto Fire Service

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