Responses of Motor-Sport Athletes to V8 Supercar Racing in Hot Conditions

2007 ◽  
Vol 2 (2) ◽  
pp. 182-191 ◽  
Author(s):  
Matt B. Brearley ◽  
James P. Finn
Keyword(s):  
Perceived Exertion ◽  
Thermal Sensation ◽  
Sweat Rate ◽  
Thermal Strain ◽  
Body Core Temperature ◽  
Hydration Status ◽  
Borg Scale ◽  
Thermal Discomfort ◽  
Body Core ◽  
Cardiovascular Strain

Background:Despite the thermal challenge of demanding workloads performed in high cabin temperatures while wearing heavy heat-retardant clothing, information on physiological responses to racing V8 Supercars in hot conditions is not readily available.Purpose:To describe the thermal, cardiovascular, and perceptual strain on V8 Supercar drivers competing in hot conditions.Methods:Thermal strain was indicated by body-core temperature using an ingested thermosensitive pill. Cardiovascular strain was assessed from heart rate, hydration status, and sweat rate. Perceptual strain was estimated from self-rated thermal sensation, thermal discomfort (modified Gagge scales), perceived exertion (Borg scale), and perceptual strain index.Results:Prerace body-core temperatures were (mean ± SD) 37.7°C ± 0.4°C (range 37.0°C to 38.2°C), rising to 39.0°C ± 0.4°C (range 38.4°C to 39.7°C) postrace. Driver heart rates were >160 and >170 beats/min for 85.3% and 46.7% of racing, respectively. Sweat rates were 1.06 ± 0.12 L/h or 13.4 ± 1.2 mL · kg−1 · h−1, and postrace dehydration was 0.6% ± 0.6% of prerace body mass. Drivers rated thermal sensation as hot (10.3 ± 0.9), thermal discomfort as uncomfortable (3.1 ± 1.0), and perceived exertion as very hard to very, very hard (8.7 ± 1.7) after the races. Overall physiological and perceptual strain were 7.4 ± 1.0 and 7.1 ± 1.2, respectively.Conclusions:Despite the use of cooling, V8 Supercar drivers endure thermal, cardiovascular, and perceptual strain during brief driving bouts in hot conditions.

scholarly journals The effect of the head or neck cooling on body core temperature and thermal sensation in humans (1104.6)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Mayumi Matsuda‐Nakamura ◽  
Satoshi Wada ◽  
Shuri Marui ◽  
Nobuo Sato ◽  
Kei Nagashima
Keyword(s):  
Core Temperature ◽  
Thermal Sensation ◽  
Body Core Temperature ◽  
Body Core ◽  
Neck Cooling

Endurance Cyclist Fluid Intake, Hydration Status, Thirst, and Thermal Sensations: Gender Differences

2016 ◽  
Vol 26 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Lawrence E. Armstrong ◽  
Evan C. Johnson ◽  
Amy L. McKenzie ◽  
Lindsay A. Ellis ◽  
Keith H. Williamson
Keyword(s):  
Gender Differences ◽  
Body Mass ◽  
Perceived Exertion ◽  
Thermal Sensation ◽  
Drinking Behavior ◽  
Field Investigation ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Exercise Time ◽  
Body Mass Change

This field investigation assessed differences (e.g., drinking behavior, hydration status, perceptual ratings) between female and male endurance cyclists who completed a 164-km event in a hot environment (35 °C mean dry bulb) to inform rehydration recommendations for athletes. Three years of data were pooled to create 2 groups of cyclists: women (n = 15) and men (n = 88). Women were significantly smaller (p < .001) than men in height (166 ± 5 vs. 179 ± 7 cm), body mass (64.6 ± 7.3 vs. 86.4 ± 12.3 kg), and body mass index (BMI; 23.3 ± 1.8 vs. 26.9 ± 3.4) and had lower preevent urinary indices of hydration status, but were similar to men in age (43 ± 7 years vs. 44 ± 9 years) and exercise time (7.77 ± 1.24 hr vs. 7.23 ± 1.75 hr). During the 164-km ride, women lost less body mass (−0.7 ± 1.0 vs. −1.7 ± 1.5 kg; −1.1 ± 1.6% vs. −1.9 ± 1.8% of body weight; p < .005) and consumed less fluid than men (4.80 ± 1.28 L vs. 5.59 ± 2.13 L; p < .005). Women consumed a similar volume of fluid as men, relative to body mass (milliliters/kilogram). To control for performance and anthropomorphic characteristics, 15 women were pair-matched with 15 men on the basis of exercise time on the course and BMI; urine-specific gravity, urine color, and body mass change (kilograms and percentage) were different (p < .05) in 4 of 6 comparisons. No gender differences were observed for ratings of thirst, thermal sensation, or perceived exertion. In conclusion, differences in relative fluid volume consumed and hydration indices suggest that professional sports medicine organizations should consider gender and individualized drinking plans when formulating pronouncements regarding rehydration during exercise.

scholarly journals Exercise under heat stress: thermoregulation, hydration, performance implications and mitigation strategies

2021 ◽  
Author(s):  
Julien D. Periard ◽  
Thijs M.H. Eijsvogels ◽  
Hein A.M. Daanen
Keyword(s):  
Heat Stress ◽  
Exercise Performance ◽  
Thermal Strain ◽  
Mitigation Strategies ◽  
Body Core Temperature ◽  
Aerobic Performance ◽  
Future Research ◽  
Hydration Status ◽  
Fatigue Development ◽  
The Impact

A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat, by examining the benefits of heat acclimation, cooling strategies and hyperhydration. Finally, contemporary controversies are summarized and future research directions provided.

scholarly journals The influence of an active microclimate liquid-cooled vest on heat strain alleviation

2020 ◽  
pp. 331-331
Author(s):  
Sveta Cvetanovic ◽  
Srdjan Rutic ◽  
Dejan Krstic ◽  
Stanislav Florus ◽  
Pavel Otrisal
Keyword(s):  
Cooling System ◽  
Sweat Rate ◽  
Heat Exposure ◽  
Thermal Strain ◽  
Experimental Results ◽  
Tympanic Temperature ◽  
Body Core Temperature ◽  
Liquid Cooling ◽  
Strain Testing ◽  
Body Cooling

This research was performed to test the effectiveness of the microclimate body cooling system which belongs to the group of active systems with liquid-cooled technology. The liquid cooling vest efficiency was observed concerning the physiological fitness of the standard protective set used in specific environmental conditions which imply increased thermal strain of the test subjects. Experimental results from the research are based on the examinations carried out in a thermo-physiological laboratory. Ten healthy male volunteers - test subjects aged (23.4 ? 2.4 years, weight 74 ? 7 kg, and height 184 ? 9 cm) were exposed to thermal strain testing (40 ?C temperature, 40?3% relative humidity, without wind) and simultaneously to physical effort caused by walking on the treadmill at a speed of 5 km/h, during 45 minutes. Tests were performed in two variants - without any cooling system (NC) and with the KewlFlow Circulatory Cooling Vest with Cooler Kit (LC). Throughout heat exposure, the subject's body core temperature (tympanic temperature - Tty), mean skin temperature (Tsk) and heart rate (HR) were measured. Furthermore, sweat rate (SwR) was calculated in order to determine all changes in the water and electrolyte status. Experimental results confirm that the results of this study have recognized the benefits of a liquid-cooled vest in lowering the thermal strain.

Effects of Hydration on Febrile Temperature Patterns in Rabbits

2001 ◽  
Vol 2 (4) ◽  
pp. 277-291 ◽  
Author(s):  
Charlotte A. Richmond
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Core Temperature ◽  
Cardiovascular Responses ◽  
Fluid Replacement ◽  
Body Core Temperature ◽  
Hydration Status ◽  
Beneficial Role ◽  
Fluid Supplementation ◽  
Body Core

Patients with fever have a predisposition to experience dehydration, which may alter their thermoregulatory responses to elevated body temperature. In view of the recent discovery of the antipyretic activity of arginine vasopressin (AVP), it is possible that dehydration has a beneficial role during fever. Dehydration may enhance endogenous antipyresis by stimulating AVP release, making aggressive fluid replacement, which may inhibit AVP release, undesirable during fever. This study addressed the effects of manipulation of hydration status on temperature and cardiovascular responses in endotoxin-injected rabbits. Eight unanesthetized chronically instrumented rabbits were exposed to lipopolysaccharide (LPS) while in euhydrated state, after furosemide (5 mg/kg) and 24 hours of water deprivation (dehydrated), after infusion of saline (30 mL/kg) while in euhydrated state (hyperhydrated), and after saline (mL/per overnight body weight loss in grams) while in dehydrated state (rehydrated). Dehydrated rabbits display higher fevers that are biphasic in nature and are accompanied by increased vasoconstriction and duration of mean arterial pressure increases, indicating that activation of antipyretic mechanisms in dehydrated rabbits was not sufficient to reduce body core temperature. In addition, fluid supplementation in euhydrated rabbits did not alter the febrile response; however, a marked decrease in heart rate was noted. Furthermore, fluid supplementation in dehydrated rabbits significantly attenuates the rectal temperature and heart rate response to LPS injection, indicating the possibility that activation of antipyretic mechanisms of AVP in rehydrated rabbits was sufficient to reduce body core temperature. The results suggest that fluid supplementation has a beneficial role in keeping body temperature lower.

A Comparative Study on the Effectiveness of Evaporative and Phase Change Material Cooling Vests for People With Paraplegia

2021 ◽  
Author(s):  
Farah Mneimneh ◽  
Nesreen Ghaddar ◽  
Kamel Ghali ◽  
Charbel Moussalem ◽  
Ibrahim Omeis
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Core Temperature ◽  
Perceived Exertion ◽  
Body Core Temperature ◽  
Light Weight ◽  
Ambient Conditions ◽  
Cord Injury ◽  
Body Core ◽  
Change Material

Abstract Personal cooling vests to alleviate thermal strain in persons with thoracic spinal cord injury (SCI), named paraplegia, were tested. Mainly, phase change material (PCM) cooling vests were the most frequent type applied at different exercises and ambient conditions. Published results of PCM cooling vests indicated its significant effect in reducing body core temperature for persons having more than 50% of their trunk skin as sensate. Nevertheless, preferences of persons with SCI obtained from subjective voting during experimental studies revealed that the use of PCM cooling vests caused additional burden weight on the body and sometimes restricted the movement. It is of interest to investigate the effect of an alternative personal evaporative cooling vest (ECV), characterized by light weight and practical use without hindering body movement of persons with SCI. In this study, it is aimed to compare the effect of ECV on the physiological and psychological responses of persons with SCI compared to that of PCM cooling vests under the same ambient conditions and metabolic rates. The research methodology included human subject experiments for persons with mid-thoracic (T4-T8) and low-thoracic (T9-T12) injury where the sensate skin of the trunk is at least 50% of its area. Thirteen participants were recruited to perform an arm-crank exercise at a constant load of 30 W for 30-min while using ECV inside a controlled climatic chamber of hot conditions (30°C, 4 0% RH). Measurements of body core and skin temperatures as well as thermal comfort and sensation, perceived exertion and skin wettedness were done. Furthermore, Multi-way ANOVA test was conducted to analyse the results of three tests: no vest (NV), with ECV, and with PCM. Findings of mid- and low-thoracic groups showed similar effectiveness of ECV compared to PCM cooling vest in reducing core temperature, yet the change in perceived exertion was better with the use of ECV due to its light weight.

scholarly journals Perceptual Responses While Wearing an American Football Uniform in the Heat

2010 ◽  
Vol 45 (2) ◽  
pp. 107-116 ◽  
Author(s):  
Evan C. Johnson ◽  
Matthew S. Ganio ◽  
Elaine C. Lee ◽  
Rebecca M. Lopez ◽  
Brendon P. McDermott ◽  
...  
Keyword(s):  
Perceived Exertion ◽  
Controlled Trial ◽  
Thermal Strain ◽  
Treadmill Walking ◽  
Rating Of Perceived Exertion ◽  
American Football ◽  
Initial Time ◽  
Hydration Status ◽  
Thermal Perception ◽  
Time Points

Abstract Context: The protective equipment worn during American football has been shown to increase thermal strain; however, the perception of this increased heat has not been examined. Objective: To evaluate perceptual responses of American football players while wearing different uniforms during exercise in the heat and to evaluate how these responses may be used to monitor athlete safety. Design: Randomized controlled trial. Setting: Human Performance Laboratory. Patients or Other Participants: Ten men with more than 3 years of competitive experience as football linemen (age  =  23.8 ± 1.3 years, height  =  183.9 ± 1.8 cm, mass  =  117.4 ± 3.5 kg, body fat  =  30.1% ± 1.7%) participated. Intervention(s): On 3 occasions in hot, humid (33°C, 48%–49% relative humidity) environmental conditions, participants completed 10 minutes of strenuous repetitive box lifting (RBL), 10 minutes of seated rest, and up to 60 minutes of treadmill walking. At each trial, they wore a different uniform condition: control (CON) clothing comprising shorts, socks, and sneakers; partial (PART) National Football League (NFL) uniform comprising the uniform without helmet or shoulder pads; or full (FULL) NFL uniform. Exercise, meals, and hydration status were controlled. Main Outcome Measure(s): Rectal temperature (Tre), skin temperature (Tsk), rating of perceived exertion (RPE), thermal perception (THM), perception of thirst (TST), and perception of muscle pain (MPN) were obtained for time points matched across trials. Results: Nineteen of the 30 trials ended before 60 minutes of treadmill walking as a result of participant exhaustion. Mean treadmill time was longer for the CON condition (51.7 ± 13.4 minutes) than for the PART (43.1 ± 15.6 minutes; t9  =  3.092, P  =  .01) or the FULL (36.2 ± 13.2 minutes; t9  =  4.393, P  =  .002) conditions. Neck and forearm Tsk increased between the initial time point and the end of exercise in the PART (33.6 ± 0.9°C and 35.0 ± 0.6°C, respectively; F2,18  =  9.034, P &lt; .001) and the FULL (33.4 ± 0.9°C and 35.2 ± 0.6°C, respectively; F2,18  =  21.011, P  =  .002) conditions. Rate of Tre rise was greater in the FULL (0.042 ± 0.010°C/min) than in the PART (0.034 ± 0.006°C/min) condition (F2,27  =  10.69, P  =  .04). We found a relationship at the post-RBL and final time points between RPE and THM (r  =  0.75, P &lt; .001 and r  =  0.59, P &lt; .001, respectively), RPE and TST (r  =  0.76, P &lt; .001 and r  =  0.61, P &lt; .001, respectively), and RPE and MPN (r  =  0.63, P &lt; .001 and r  =  0.64, P &lt; .001, respectively). The RPE was greater at the end of exercise in the PART (17 ± 2) and FULL (18 ± 1) conditions than in the CON (15 ± 3) condition (F2,18  =  7.403, P  =  .005). Conclusions: Although no differences in perceptual scales existed between the PART and FULL conditions, the Tsk and rate of Tre increase differed, indicating that football athletes find it difficult to perceptually rate exercise conditions as potentially dangerous hyperthermia develops. In addition, correlations between the perceptual scales further defined perceptual responses during exercise in the heat.

scholarly journals Intermittent sprint performance in the heat is not altered by augmenting thermal perception via L-Menthol or Capsaicin mouth rinses

2018 ◽  
Author(s):  
Oliver Gibson ◽  
James Graeme Wrightson ◽  
Mark Hayes
Keyword(s):  
Perceived Exertion ◽  
Thermal Sensation ◽  
Sweat Rate ◽  
Sprint Performance ◽  
Thermal Perception ◽  
Mouth Rinses ◽  
Experimental Trials ◽  
Mouth Rinsing ◽  
The Impact ◽  
Over Time

Purpose. Cooling sensations elicited by mouth rinsing with L-Menthol have been reported as ergogenic. Presently, responses to L-Menthol mouth rinsing during intermittent sprint performance (ISP) in the heat are unknown and the impact of increased thermal perception on ISP via Capsaicin has also not been quantified. This experiment aimed to identify whether eliciting cooling/warming sensations via L-Menthol/Capsaicin would alter ISP in the heat.Method. Fourteen participants [mass=72±9 kg, V̇O2peak=3.30±0.90 L.min-1], undertook four experimental trials, involving 40 min of ISP in hot conditions (40.2±0.6°C, 42±2%R.H.) with mouth rinsing (25 mL, 6 sec) at the protocol onset, and every 10 min thereafter. Cooling (0.01%L-Menthol; MEN), warming (0.2%Capsaicin; CAP), placebo (0.3 sham-CHO; PLA) and control (water; CON) mouth rinses were utilised. Performance was quantified via power (PP) and work done (WD) during sprints. Heart rate (HR), core (Trec) and skin (Tskin) temperature, perceived exertion (RPE), thermal sensation (Tsens) and comfort (Tcom) were measured at 10 min intervals. Sweat rate (WBSR) was calculated from ∆mass. Result. PP reduced over time (P&lt;0.05), however no change was observed between trials for PP or WD (P&gt;0.05). Tcom increased over time and was lower in MEN (2.7±1.1; P&lt;0.05) with no difference between CAP (3.1±1.2), PLA (3.2±1.3) and CON (3.1±1.3). RPE, Tsens HR, Trec, Tskin increased over time (P&lt;0.05) with no between trial differences (P&gt;0.05). Conclusion. Despite improved thermal comfort via L-Menthol, ISP did not improve. Capsaicin did not alter thermal perception or ISP. The reduction in ISP over time in hot conditions is not influenced by thermal perception.

scholarly journals Effect of Clothing Fabric on 20-km Cycling Performance in Endurance Athletes

2022 ◽  
Vol 3 ◽  
Author(s):  
Jared Ferguson ◽  
Amir Hadid ◽  
Yoram Epstein ◽  
Dennis Jensen
Keyword(s):  
Perceived Exertion ◽  
Thermal Sensation ◽  
Sweat Rate ◽  
Time Trial ◽  
Cycling Performance ◽  
Experimental Conditions ◽  
Cycling Time Trial ◽  
Competitive Cyclists ◽  
Skin Temperatures ◽  
Simulated Wind

Purpose: Examine the effect of synthetic fabrics (SYN, 60% polyester: 40% nylon) vs. 100% cotton fabric (CTN) on the 20-km cycling time trial (20 kmCTT) performance of competitive cyclists and triathletes.Methods: In this randomized controlled crossover study, 15 adults (5 women) aged 29.6 ± 2.7 years (mean ± SE) with a peak rate of O2 consumption of 60.0 ± 2.0 ml/kg/min completed a 20 kmCTT under ambient laboratory conditions (24.3 ± 0.7°C and 17 ± 7% relative humidity) with a simulated wind of ~3 m/s while wearing SYN or CTN clothing ensembles. Both ensembles were of snowflake mesh bi-layer construction and consisted of a loose-fitting long-sleeved shirt with full-length trousers.Results: Participants maintained a significantly (p &lt; 0.05) higher cycling speed and power output over the last 6-km of the 20 kmCTT while wearing the SYN vs. CTN ensemble (e.g., by 0.98 km/h and 18.4 watts at the 20-km mark). Consequently, 20 kmCTT duration was significantly reduced by 15.7 ± 6.8 sec or 0.8 ± 0.3% during SYN vs. CTN trials (p &lt; 0.05). Improved 20 kmCTT performance with SYN vs. CTN clothing could not be explained by concurrent differences in esophageal temperature, sweat rate, ratings of perceived exertion and/or cardiometabolic responses to exercise. However, it was accompanied by significantly lower mean skin temperatures (~1°C) and more favorable ratings of perceived clothing comfort and thermal sensation during exercise.Conclusion: Under the experimental conditions of the current study, athletic clothing made of synthetic fabrics significantly improved the 20 kmCTT performance of endurance-trained athletes by optimizing selected thermoregulatory and perceptual responses to exercise.

scholarly journals Effects of Casein Hydrolysate Ingestion on Thermoregulatory Responses in Healthy Adults during Exercise in Heated Conditions: A Randomized Crossover Trial

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 867
Author(s):  
Yasuyuki Sakata ◽  
Chikako Yoshida ◽  
Yuka Fujiki ◽  
Yutaka Matsunaga ◽  
Hirohiko Nakamura ◽  
...  
Keyword(s):  
Amino Acid ◽  
Skin Temperature ◽  
Core Temperature ◽  
Acid Concentration ◽  
Crossover Trial ◽  
Sweat Rate ◽  
Casein Hydrolysate ◽  
Amino Acid Concentration ◽  
Body Core Temperature ◽  
Body Core

Food ingestion has been shown to affect thermoregulation during exercise, while the impact of protein degradant consumption remains unclear. We investigated the effects of casein hydrolysate ingestion on thermoregulatory responses during exercise in the heat. In a randomized, placebo-controlled, double-blind, crossover trial, five men and five women consumed either 5 g of casein hydrolysate or placebo. Thirty minutes after ingestion, participants cycled at 60% VO2max until voluntary exhaustion wearing a hot-water (43 °C) circulation suit. Exercise time to exhaustion, body core temperature, forearm sweat rate, and forearm cutaneous vascular conductance did not differ different between the conditions. However, chest sweat rate and mean skin temperature increased upon casein hydrolysate ingestion compared with placebo during exercise. Increased chest sweat rate upon casein hydrolysate ingestion was associated with elevated sudomotor sensitivity to increasing body core temperature, but not the temperature threshold for initiating sweating. A positive correlation was found between chest sweat rate and plasma total amino acid concentration during exercise. These results suggest that casein hydrolysate ingestion enhances sweating heterogeneously by increasing peripheral sensitivity of the chest’s sweating mechanism and elevating skin temperature during exercise in the heat. However, the physiological link between plasma amino acid concentration and sweat rate remains unclear.

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