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Abstract
The application of menthol has recently been researched as a performance-enhancing aid for various aspects of athletic performance including endurance, speed, strength and joint range of motion. A range of application methods has been used including a mouth rinse, ingestion of a beverage containing menthol or external application to the skin or clothing via a gel or spray. The majority of research has focussed on the use of menthol to impart a cooling sensation on athletes performing endurance exercise in the heat. In this situation, menthol appears to have the greatest beneficial effect on performance when applied internally. In contrast, the majority of investigations into the external application of menthol demonstrated no performance benefit. While studies are limited in number, menthol has not yet proven to be beneficial for speed or strength, and only effective at increasing joint range of motion following exercise that induced delayed-onset muscle soreness. Internal application of menthol may provoke such performance-enhancing effects via mechanisms related to its thermal, ventilatory, analgesic and arousing properties. Future research should focus on well-trained subjects and investigate the addition of menthol to nutritional sports products.
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Affiliation(s)
- Christopher J Stevens
- School of Health and Human Sciences, Southern Cross University, Hogbin Drive, Coffs Harbour, NSW, 2450, Australia.
| | - Russ Best
- School of Social Sciences, Business and Law, Teesside University, Middlesbrough, UK
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Abstract
Menthol is a compound of plant origin and has recently been used to aid exercise performance in hot, humid environments. Menthol creates a sensation of coolness when applied to the skin or mucosal surfaces stimulating the cold receptors. In these environments, fatigue is known to be accelerated and feelings of being hot are one of the main contributors to the early onset of fatigue. However, current research indicates that nonthermal perceptual cooling interventions could alter behavior in the heat by reducing thermal perception. This would allow the athlete to feel cooler when exercising at the same work rate in the heat. Menthol has been investigated as an internal and external intervention. Greater benefits have currently been found for internal interventions than external methods. Future research should focus on the mechanisms, dosage, and timing of both internal and external interventions, and the role menthol could play within speed or strength.
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Affiliation(s)
- Tessa Rose Flood
- University of Chichester, UK College Lane University of Chichester, West Sussex, UNITED KINGDOM
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Best R, Payton S, Spears I, Riera F, Berger N. Topical and Ingested Cooling Methodologies for Endurance Exercise Performance in the Heat. Sports (Basel) 2018; 6:sports6010011. [PMID: 29910315 PMCID: PMC5969198 DOI: 10.3390/sports6010011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 01/14/2023] Open
Abstract
This systematic review and meta-analysis aimed to assess studies which have investigated cooling methodologies, their timing and effects, on endurance exercise performance in trained athletes (Category 3; VO2max ≥ 55 mL·kg·min−1) in hot environmental conditions (≥28 °C). Meta-analyses were performed to quantify the effects of timings and methods of application, with a narrative review of the evidence also provided. A computer-assisted database search was performed for articles investigating the effects of cooling on endurance performance and accompanying physiological and perceptual responses. A total of 4129 results were screened by title, abstract, and full text, resulting in 10 articles being included for subsequent analyses. A total of 101 participants and 310 observations from 10 studies measuring the effects of differing cooling strategies on endurance exercise performance and accompanying physiological and perceptual responses were included. With respect to time trial performance, cooling was shown to result in small beneficial effects when applied before and throughout the exercise bout (Effect Size: −0.44; −0.69 to −0.18), especially when ingested (−0.39; −0.60 to −0.18). Current evidence suggests that whilst other strategies ameliorate physiological or perceptual responses throughout endurance exercise in hot conditions, ingesting cooling aids before and during exercise provides a small benefit, which is of practical significance to athletes’ time trial performance.
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Affiliation(s)
- Russ Best
- School of Social Sciences, Humanities & Law, Teesside University, Middlesbrough TS1 3BX, UK.
- Centre for Sports Science and Human Performance, Waikato Institute of Technology, Hamilton 3288, New Zealand.
| | | | - Iain Spears
- Pro-Football Support Ltd., Huddersfield HD7 5BQ, UK.
| | - Florence Riera
- Laboratoire ACTES⁻EA 3596, Université des Antilles et de la Guyane, 97157 Pointe à Pitre, France.
- Laboratoire LEPSA⁻EA 4604, Université de Perpignan, 66120 Font Romeu, France.
| | - Nicolas Berger
- School of Social Sciences, Humanities & Law, Teesside University, Middlesbrough TS1 3BX, UK.
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Li C, Li J, Xiong X, Liu Y, Lv Y, Qin S, Liu D, Wei R, Ruan X, Zhang J, Xu L, Wang X, Chen J, Zhang Y, Zheng L. TRPM8 activation improves energy expenditure in skeletal muscle and exercise endurance in mice. Gene 2018; 641:111-116. [DOI: 10.1016/j.gene.2017.10.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 10/06/2017] [Accepted: 10/16/2017] [Indexed: 10/18/2022]
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Flood TR, Waldron M, Jeffries O. Oral L-menthol reduces thermal sensation, increases work-rate and extends time to exhaustion, in the heat at a fixed rating of perceived exertion. Eur J Appl Physiol 2017; 117:1501-1512. [PMID: 28508114 DOI: 10.1007/s00421-017-3645-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 05/10/2017] [Indexed: 12/30/2022]
Abstract
PURPOSE The study investigated the effect of a non-thermal cooling agent, L-menthol, on exercise at a fixed subjective rating of perceived exertion (RPE) in a hot environment. METHOD Eight male participants completed two trials at an exercise intensity between 'hard' and 'very hard', equating to 16 on the RPE scale at ~35 °C. Participants were instructed to continually adjust their power output to maintain an RPE of 16 throughout the exercise trial, stopping once power output had fallen by 30%. In a randomized crossover design, either L-menthol or placebo mouthwash was administered prior to exercise and at 10 min intervals. Power output, [Formula: see text]O2, heart rate, core and skin temperature was monitored, alongside thermal sensation and thermal comfort. Isokinetic peak power sprints were conducted prior to and immediately after the fixed RPE trial. RESULTS Exercise time was greater (23:23 ± 3:36 vs. 21:44 ± 2:32 min; P = 0.049) and average power output increased (173 ± 24 vs. 167 ± 24 W; P = 0.044) in the L-menthol condition. Peak isokinetic sprint power declined from pre-post trial in the L-menthol l (9.0%; P = 0.015) but not in the placebo condition (3.4%; P = 0.275). Thermal sensation was lower in the L-menthol condition (P = 0.036), despite no changes in skin or core temperature (P > 0.05). CONCLUSION These results indicate that a non-thermal cooling mouth rinse lowered thermal sensation, resulting in an elevated work rate, which extended exercise time in the heat at a fixed RPE.
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Affiliation(s)
- T R Flood
- School of Sport, Health and Applied Science, St Mary's University, Waldegrave Road, Twickenham, London, TW1 4SX, UK
- School of Sport and Exercise Science, University of Chichester, Chichester, UK
| | - M Waldron
- School of Sport, Health and Applied Science, St Mary's University, Waldegrave Road, Twickenham, London, TW1 4SX, UK
- School of Science and Technology, University of New England, Armidale, NSW, Australia
| | - O Jeffries
- School of Sport, Health and Applied Science, St Mary's University, Waldegrave Road, Twickenham, London, TW1 4SX, UK.
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Stevens CJ, Bennett KJ, Sculley DV, Callister R, Taylor L, Dascombe BJ. A Comparison of Mixed-Method Cooling Interventions on Preloaded Running Performance in the Heat. J Strength Cond Res 2017; 31:620-629. [DOI: 10.1519/jsc.0000000000001532] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bongers CCWG, Hopman MTE, Eijsvogels TMH. Cooling interventions for athletes: An overview of effectiveness, physiological mechanisms, and practical considerations. Temperature (Austin) 2017; 4:60-78. [PMID: 28349095 PMCID: PMC5356217 DOI: 10.1080/23328940.2016.1277003] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/22/2016] [Accepted: 12/22/2016] [Indexed: 02/08/2023] Open
Abstract
Exercise-induced increases in core body temperature could negative impact performance and may lead to development of heat-related illnesses. The use of cooling techniques prior (pre-cooling), during (per-cooling) or directly after (post-cooling) exercise may limit the increase in core body temperature and therefore improve exercise performance. The aim of the present review is to provide a comprehensive overview of current scientific knowledge in the field of pre-cooling, per-cooling and post-cooling. Based on existing studies, we will discuss 1) the effectiveness of cooling interventions, 2) the underlying physiological mechanisms and 3) practical considerations regarding the use of different cooling techniques. Furthermore, we tried to identify the optimal cooling technique and compared whether cooling-induced performance benefits are different between cool, moderate and hot ambient conditions. This article provides researchers, physicians, athletes and coaches with important information regarding the implementation of cooling techniques to maintain exercise performance and to successfully compete in thermally stressful conditions.
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Affiliation(s)
- Coen C W G Bongers
- Radboud Institute of Health Sciences, Radboud university medical center, Department of Physiology , Nijmegen, The Netherlands
| | - Maria T E Hopman
- Radboud Institute of Health Sciences, Radboud university medical center, Department of Physiology , Nijmegen, The Netherlands
| | - Thijs M H Eijsvogels
- Radboud Institute of Health Sciences, Radboud university medical center, Department of Physiology, Nijmegen, The Netherlands; Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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Hutchings SC, Horner KM, Dible VA, Grigor JM, O'Riordan D. Modification of aftertaste with a menthol mouthwash reduces food wanting, liking, and ad libitum intake of potato crisps. Appetite 2017; 108:57-67. [DOI: 10.1016/j.appet.2016.09.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 01/12/2023]
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Stevens CJ, Taylor L, Dascombe BJ. Cooling During Exercise: An Overlooked Strategy for Enhancing Endurance Performance in the Heat. Sports Med 2016; 47:829-841. [DOI: 10.1007/s40279-016-0625-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Stevens CJ, Thoseby B, Sculley DV, Callister R, Taylor L, Dascombe BJ. Running performance and thermal sensation in the heat are improved with menthol mouth rinse but not ice slurry ingestion. Scand J Med Sci Sports 2015; 26:1209-16. [PMID: 26408395 DOI: 10.1111/sms.12555] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2015] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to compare the effects of a cooling strategy designed to predominately lower thermal state with a strategy designed to lower thermal sensation on endurance running performance and physiology in the heat. Eleven moderately trained male runners completed familiarization and three randomized, crossover 5-km running time trials on a non-motorized treadmill in hot conditions (33 °C). The trials included ice slurry ingestion before exercise (ICE), menthol mouth rinse during exercise (MEN), and no intervention (CON). Running performance was significantly improved with MEN (25.3 ± 3.5 min; P = 0.01), but not ICE (26.3 ± 3.2 min; P = 0.45) when compared with CON (26.0 ± 3.4 min). Rectal temperature was significantly decreased with ICE (by 0.3 ± 0.2 °C; P < 0.01), which persisted for 2 km of the run and MEN significantly decreased perceived thermal sensation (between 4 and 5 km) and ventilation (between 1 and 2 km) during the time trial. End-exercise blood prolactin concentration was elevated with MEN compared with CON (by 25.1 ± 24.4 ng/mL; P = 0.02). The data demonstrate that a change in the perception of thermal sensation during exercise from menthol mouth rinse was associated with improved endurance running performance in the heat. Ice slurry ingestion reduced core temperature but did not decrease thermal sensation during exercise or improve running performance.
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Affiliation(s)
- C J Stevens
- Applied Sports Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of Newcastle, Ourimbah, Australia.
| | - B Thoseby
- Applied Sports Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of Newcastle, Ourimbah, Australia
| | - D V Sculley
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, Australia
| | - R Callister
- Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, Australia.,School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, Australia
| | - L Taylor
- Applied Sport and Exercise Physiology (ASEP) Research Group, Department of Sport Science and Physical Activity, Institute for Sport and Physical Activity Research (ISPAR), University of Bedfordshire, Bedford, UK
| | - B J Dascombe
- Applied Sports Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of Newcastle, Ourimbah, Australia.,Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, Australia
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Tran Trong T, Riera F, Rinaldi K, Briki W, Hue O. Ingestion of a cold temperature/menthol beverage increases outdoor exercise performance in a hot, humid environment. PLoS One 2015; 10:e0123815. [PMID: 25856401 PMCID: PMC4391868 DOI: 10.1371/journal.pone.0123815] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 03/07/2015] [Indexed: 11/24/2022] Open
Abstract
Purpose A recent laboratory study demonstrated that the ingestion of a cold/menthol beverage improved exercise performance in a hot and humid environment during 20 km of all-out cycling. Therefore, the aim of this study was to determine whether the ingestion of cold water/ice-slurry with menthol would improve performance in hot and humid outdoor conditions. Methods Ten trained males completed three trials of five blocks consisting of 4-km cycling and 1.5-km running. During warm-up, every block and recovery, the athletes drank 190 ml of aromatized (i.e., with 0.05 mL of menthol) beverage at three temperatures: Neutral (ambient temperature) (28.7°C±0. 5°C), Cold (3.1°C±0.6°C) or Ice-slurry (0.17°C±0.07°C). Trial time, core temperature (Tco), heart rate (HR), rate of perceived exertion (RPE), thermal sensation (TS) and thermal comfort (TC) were assessed. Results Ice-slurry/menthol increased performance by 6.2% and 3.3% compared with neutral water/menthol and cold water/menthol, respectively. No between-trial differences were noted for Tco, HR, RPE, TC and TS was lower with ice-slurry/menthol and cold water/menthol compared with neutral water/menthol. Conclusion A low drink temperature combined with menthol lessens the performance decline in hot/humid outdoor conditions (i.e., compared with cold water alone). Performances were better with no difference in psycho-physiological stress (Tco, HR and RPE) between trials. The changes in perceptual parameters caused by absorbing a cold/menthol beverage reflect the psychological impact. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources.
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Affiliation(s)
- Than Tran Trong
- Laboratoire ACTES—EA 3596, Université des Antilles et de la Guyane, Campus de Fouillole, Point à Pitre, France
| | - Florence Riera
- Laboratoire ACTES—EA 3596, Université des Antilles et de la Guyane, Campus de Fouillole, Point à Pitre, France
- * E-mail:
| | - Kévin Rinaldi
- Laboratoire ACTES—EA 3596, Université des Antilles et de la Guyane, Campus de Fouillole, Point à Pitre, France
| | - Walid Briki
- Laboratoire ACTES—EA 3596, Université des Antilles et de la Guyane, Campus de Fouillole, Point à Pitre, France
| | - Olivier Hue
- Laboratoire ACTES—EA 3596, Université des Antilles et de la Guyane, Campus de Fouillole, Point à Pitre, France
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Burke LM, Maughan RJ. The Governor has a sweet tooth - mouth sensing of nutrients to enhance sports performance. Eur J Sport Sci 2014; 15:29-40. [PMID: 25345670 DOI: 10.1080/17461391.2014.971880] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The oral-pharyngeal cavity and the gastrointestinal tract are richly endowed with receptors that respond to taste, temperature and to a wide range of specific nutrient and non-nutritive food components. Ingestion of carbohydrate-containing drinks has been shown to enhance endurance exercise performance, and these responses have been attributed to post-absorptive effects. It is increasingly recognised, though, that the response to ingested carbohydrate begins in the mouth via specific carbohydrate receptors and continues in the gut via the release of a range of hormones that influence substrate metabolism. Cold drinks can also enhance performance, especially in conditions of thermal stress, and part of the mechanism underlying this effect may be the response to cold fluids in the mouth. There is also some, albeit not entirely consistent, evidence for effects of caffeine, quinine, menthol and acetic acid on performance or other relevant effects. This review summarises current knowledge of responses to mouth sensing of temperature, carbohydrate and other food components, with the goal of assisting athletes to implement practical strategies that make best use of its effects. It also examines the evidence that oral intake of other nutrients or characteristics associated with food/fluid intake during exercise can enhance performance via communication between the mouth/gut and the brain.
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Affiliation(s)
- Louise M Burke
- a Sports Nutrition , Australian Institute of Sport , Belconnen , ACT 2616 , Australia
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64
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Riera F, Trong TT, Sinnapah S, Hue O. Physical and perceptual cooling with beverages to increase cycle performance in a tropical climate. PLoS One 2014; 9:e103718. [PMID: 25084009 PMCID: PMC4118924 DOI: 10.1371/journal.pone.0103718] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 07/06/2014] [Indexed: 11/19/2022] Open
Abstract
Purpose This study compares the effects of neutral temperature, cold and ice-slush beverages, with and without 0.5% menthol on cycling performance, core temperature (Tco) and stress responses in a tropical climate (hot and humid conditions). Methods Twelve trained male cyclists/triathletes completed six 20-km exercise trials against the clock in 30.7°C±0.8°C and 78%±0.03% relative humidity. Before and after warm-up, and before exercise and every 5 km during exercise, athletes drank 190 mL of either aromatized (i.e., with 0.5 mL of menthol (5 gr/L)) or a non-aromatized beverage (neutral temperature: 23°C±0.1°C, cold: 3°C±0.1°C, or ice-slush: −1°C±0.7°C). During the trials, heart rate (HR) was continuously monitored, whereas core temperature (Tco), thermal comfort (TC), thermal sensation (TS) and rate of perceived exertion (RPE) were measured before and after warm-up, every 5 km of exercise, and at the end of exercise and after recovery. Results Both the beverage aroma (P<0.02) and beverage temperature (P<0.02) had significant and positive effects on performance, which was considerably better with ice-slush than with a neutral temperature beverage, whatever the aroma (P<0.002), and with menthol vs non-menthol (P<0.02). The best performances were obtained with ice-slush/menthol and cold/menthol, as opposed to neutral/menthol. No differences were noted in HR and Tco between trials. Conclusion Cold water or ice-slush with menthol aroma seems to be the most effective beverage for endurance exercise in a tropical climate. Further studies are needed to explore its effects in field competition.
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Affiliation(s)
- Florence Riera
- Laboratoire ACTES - EA 3596, Université des Antilles et de la Guyane Campus de Fouillole, Point à Pitre, France
- * E-mail:
| | - Than Tran Trong
- Laboratoire ACTES - EA 3596, Université des Antilles et de la Guyane Campus de Fouillole, Point à Pitre, France
| | - Stéphane Sinnapah
- Laboratoire ACTES - EA 3596, Université des Antilles et de la Guyane Campus de Fouillole, Point à Pitre, France
| | - Olivier Hue
- Laboratoire ACTES - EA 3596, Université des Antilles et de la Guyane Campus de Fouillole, Point à Pitre, France
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Burdon CA, Easthope CS, Johnson NA, Chapman PG, O'Connor H. The influence of ice slushy on voluntary contraction force following exercise-induced hyperthermia. Appl Physiol Nutr Metab 2014; 39:781-6. [PMID: 24971678 DOI: 10.1139/apnm-2013-0394] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study aimed to investigate the effect of exercise-induced hyperthermia on central fatigue and force decline in exercised and nonexercised muscles and whether ingestion of ice slushy (ICE) ameliorates fatigue. Eight participants (5 males, 3 females) completed 45 s maximal voluntary isometric contractions (MVIC) with elbow flexors and knee extensors at baseline and following an exercise-induced rectal temperature (Trec) of 39.3 ± 0.2 °C. Percutaneous electrical muscle stimulation was superimposed at 15, 30 and 44 s during MVICs to assess muscle activation. To increase Trec to 39.3 °C, participants cycled at 60% maximum power output for 42 ± 11 min in 40 °C and 50% relative humidity. Immediately prior to each MVIC, participants consumed 50 g of ICE (-1 °C) or thermoneutral drink (38 °C, CON) made from 7.4% carbohydrate beverage. Participants consumed water (19 °C) during exercise to prevent hypohydration. Voluntary muscle force production and activation in both muscle groups were unchanged at Trec 39.3 °C with ICE (knee extensors: 209 ± 152 N) versus CON (knee extensors: 255 ± 157 N, p = 0.19). At Trec 39.3 °C, quadriceps mean force (232 ± 151 N) decreased versus baseline (302 ± 180 N, p < 0.001) and mean voluntary activation was also decreased (by 15% ± 11%, p < 0.001). Elbow flexor mean force decreased from 179 ± 67 N to 148 ± 65 N when Trec was increased to 39.3 °C (p < 0.001) but mean voluntary activation was not reduced at 39.3 °C (5% ± 25%, p = 0.79). After exercise-induced hyperthermia, ICE had no effect on voluntary activation or force production; however, both were reduced from baseline in the exercised muscle group. Peripheral fatigue was greater than the central component and limited the ability of an intervention designed to alter central fatigue.
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Affiliation(s)
- Catriona A Burdon
- a Exercise and Sport Science, University of Sydney, 75 East St., Lidcombe 2141, NSW, Australia
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66
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Zhang Y, Balilionis G, Casaru C, Geary C, Schumacker RE, Neggers YH, Curtner-Smith MD, Richardson MT, Bishop PA, Green JM. Effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat. APPLIED ERGONOMICS 2014; 45:510-514. [PMID: 23891504 DOI: 10.1016/j.apergo.2013.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 06/30/2013] [Accepted: 07/05/2013] [Indexed: 06/02/2023]
Abstract
This study examined the separate effects of caffeine and menthol on cognition and mood during simulated firefighting in the heat. Participants (N = 10) performed three trials in a counterbalanced order, either with 400 mg caffeine, menthol lozenges, or placebo. The simulated firefighting consisted of 2 bouts of 20-min treadmill exercise and one bout of 20-min stepping exercise in the heat with two brief 15-min rest periods between each exercise phase. Exercise induced significant dehydration (>3%) and elevated rectal temperature (>38.9 °C), for all three conditions. Neither caffeine nor menthol reduced perceived exertion compared to placebo (p > 0.05). Mood ratings (i.e., alertness, hedonic tone, tension) significantly deteriorated over time (p < 0.05), but there was no difference among the three conditions. Simple reaction time, short-term memory, and retrieval memory did not alter with treatments or repeated evaluations. Reaction accuracy from a math test remained unchanged throughout the experimental period; reaction time from the math test was significantly faster after exposure to the heat (p < 0.05). It is concluded that, exhaustive exercise in the heat severely impacted mood, but minimally impacted cognition. These treatments failed to show ergogenic benefits in a simulated firefighting paradigm in a hot environment.
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Affiliation(s)
- Yang Zhang
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | - Gytis Balilionis
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Catalina Casaru
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Colleen Geary
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Randall E Schumacker
- Department of Educational Studies in Psychology, Research Methodology, and Counseling, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Yasmin H Neggers
- Department of Human Nutrition, The University of Alabama, Tuscaloosa, AL 35487, USA
| | | | - Mark T Richardson
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Phillip A Bishop
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - James M Green
- Department of Health, Physical Education, and Recreation, University of North Alabama, Florence, AL 35632, USA
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67
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Che Muhamed AM, Mohamed NG, Ismail N, Aziz AR, Singh R. Mouth rinsing improves cycling endurance performance during Ramadan fasting in a hot humid environment. Appl Physiol Nutr Metab 2013; 39:458-64. [PMID: 24669987 DOI: 10.1139/apnm-2013-0276] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the effect of mouth rinsing during endurance cycling in a hot humid environment (32 °C and 75% relative humidity) on athletes in the Ramadan fasted state. Nine trained adolescent male cyclists completed 3 trials that consisted of a carbohydrate mouth-rinse (CMR), a placebo mouth-rinse (PMR), and a no-rinse (NOR) trial during the last 2 weeks of Ramadan. Each trial consisted of a preloading cycle at 65% peak rate of oxygen consumption for 30 min followed by a 10-km time trial (TT10 km) under hot humid condition. During the CMR and PMR trials, each cyclist rinsed his mouth with 25 mL of the solution for 5 s before expectorating the solution pre-exercise, after 5, 15, and 25 min of the preloading cycle, and 15 s prior to the start of TT10 km. Time to complete the TT10 km was significantly faster in the CMR and PMR trials compared with the NOR trial (12.9 ± 1.7 and 12.6 ± 1.7 vs. 16.8 ± 1.6 min, respectively; p < 0.017). Ratings of perceived exertion taken at the end of the TT10 km was lower in both CMR and PMR trials compared with the NOR trial, although the difference was significant only between CMR and NOR (p < 0.05). In conclusion, mouth rinsing with either carbohydrate or placebo solution provided ergogenic benefits compared with a no-rinse condition on TT10 km performance in acute Ramadan fasted subjects during endurance cycling in a heat stress environment.
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Affiliation(s)
- Ahmad Munir Che Muhamed
- a Lifestyle Science Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Bertam, 13200, Kepala Batas Penang, Malaysia
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68
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Precooling methods and their effects on athletic performance : a systematic review and practical applications. Sports Med 2013; 43:207-25. [PMID: 23329610 DOI: 10.1007/s40279-012-0014-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Precooling is a popular strategy used to combat the debilitating effects of heat-stress-induced fatigue and extend the period in which an individual can tolerate a heat-gaining environment. Interest in precooling prior to sporting activity has increased over the past three decades, with options including the application (external) and ingestion (internal) of cold modalities including air, water and/or ice, separately or in combination, immediately prior to exercise. Although many studies have observed improvements in exercise capacity or performance following precooling, some strategies are more logistically challenging than others, and thus are often impractical for use in competition or field settings. OBJECTIVE The purpose of this article was to comprehensively evaluate the established precooling literature, which addresses the application of cooling strategies that are likely to enhance field-based sports performance, while discussing the practical and logistical issues associated with these methods. We undertook a narrative examination that focused on the practical and event-specific application of precooling and its effect on physiological parameters and performance. DATA SOURCES Relevant precooling literature was located through the PubMed database with second- and third-order reference lists manually cross matched for relevant journal articles. The last day of the literature search was 31 January 2012. STUDY SELECTION Relevant studies were included on the basis of conforming to strict criteria, including the following: (i) cooling was conducted before exercise; (ii) cooling was conducted during the performance task in a manner that was potentially achievable during sports competition; (iii) a measure of athletic performance was assessed; (iv) subjects included were able bodied, and free of diseases or disorders that would affect thermoregulation; (v) subjects were endurance-trained humans (maximal oxygen uptake [[Formula: see text]O(2max)] >50 ml/kg/min for endurance protocols); (vi) cooling was not performed on already hyperthermic subjects that were in immediate danger of heat-related illnesses or had received passive heating treatments; (vii) drink ingestion protocols were used for the intended purpose of benefiting thermoregulation as a result of beverage temperature; and (viii) investigations employed ≥ six subjects. Initial searches yielded 161 studies, but 106 were discarded on failing to meet the established criteria. This final summary evaluated 74 precooling treatments, across 55 studies employing well trained subjects. STUDY APPRAISAL AND SYNTHESIS METHODS Key physiological and performance information from each study was extracted and presented, and includes respective subject characteristics, detailed precooling methods, exercise protocols, environmental conditions, along with physiological and performance outcomes. Data were presented in comparison to respective control treatments. For studies that include more than one treatment intervention, the comparative results between each precooling treatment were also presented. The practical benefits and limitations of employing each strategy in the field and in relation to sports performance were summarized. RESULTS Clear evidence of the benefits for a range of precooling strategies undertaken in the laboratory setting exists, which suggest that these strategies could be employed by athletes who compete in hot environmental conditions to improve exercise safety, reduce their perceived thermal stress and improve sports performance. LIMITATIONS This review did not include a systematic assessment of the study quality rating and provided a subjective assessment of the pooled outcomes of studies, which range in precooling methodologies and exercise outcomes. The wide range of research designs, precooling methods, environmental conditions and exercise protocols make it difficult to integrate all the available research into single findings. CONCLUSION Most laboratory studies have shown improvements in exercise performance following precooling and the emergence of strategies that are practically relevant to the field setting now allow scientists to individualize relevant strategies for teams and individuals at competition locations. Future research is warranted to investigate the effectiveness of practical precooling strategies in competition or field settings.
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Byrne C, Owen C, Cosnefroy A, Lee JKW. Self-paced exercise performance in the heat after pre-exercise cold-fluid ingestion. J Athl Train 2012; 46:592-9. [PMID: 22488183 DOI: 10.4085/1062-6050-46.6.592] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Precooling is the pre-exercise reduction of body temperature and is an effective method of improving physiologic function and exercise performance in environmental heat. A practical and effective method of precooling suitable for application at athletic venues has not been demonstrated. OBJECTIVE To confirm the effectiveness of pre-exercise ingestion of cold fluid without fluid ingestion during exercise on pre-exercise core temperature and to determine whether pre-exercise ingestion of cold fluid alone without continued provision of cold fluid during exercise can improve exercise performance in the heat. DESIGN Randomized controlled clinical trial. SETTING Environmental chamber at an exercise physiology laboratory that was maintained at 32°C, 60% relative humidity, and 3.2 m/s facing air velocity. PATIENTS OR OTHER PARTICIPANTS Seven male recreational cyclists (age = 21 ± 1.5 years, height = 1.81 ± 0.07 m, mass = 78.4 ± 9.2 kg) participated. INTERVENTION(S) Participants ingested 900 mL of cold (2°C) or control (37°C) flavored water in 3 300-mL aliquots over 35 minutes of pre-exercise rest. MAIN OUTCOME MEASURE(S) Rectal temperature and thermal comfort before exercise and distance cycled, power output, pacing, rectal temperature, mean skin temperature, heart rate, blood lactate, thermal comfort, perceived exertion, and sweat loss during exercise. RESULTS During rest, a greater decrease in rectal temperature was observed with ingestion of the cold fluid (0.41 ± 0.16°C) than the control fluid (0.17 ± 0.17°C) over 35 to 5 minutes before exercise (t(6) = -3.47, P = .01). During exercise, rectal temperature was lower after ingestion of the cold fluid at 5 to 25 minutes (t(6) range, 2.53-3.38, P ≤ .05). Distance cycled was greater after ingestion of the cold fluid (19.26 ± 2.91 km) than after ingestion of the control fluid (18.72 ± 2.59 km; t(6) = -2.80, P = .03). Mean power output also was greater after ingestion of the cold fluid (275 ± 27 W) than the control fluid (261 ± 22 W; t(6) = -2.13, P = .05). No differences were observed for pacing, mean skin temperature, heart rate, blood lactate, thermal comfort, perceived exertion, and sweat loss (P > .05). CONCLUSIONS We demonstrated that pre-exercise ingestion of cold fluid is a simple, effective precooling method suitable for field-based application.
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TYLER CHRISTOPHERJAMES, SUNDERLAND CAROLINE. Neck Cooling and Running Performance in the Heat. Med Sci Sports Exerc 2011; 43:2388-95. [DOI: 10.1249/mss.0b013e318222ef72] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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71
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Body regional influences of L-menthol application on the alleviation of heat strain while wearing firefighter's protective clothing. Eur J Appl Physiol 2011; 112:2171-83. [PMID: 21964942 DOI: 10.1007/s00421-011-2192-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Accepted: 09/21/2011] [Indexed: 12/16/2022]
Abstract
The purpose of this study was to investigate the influences of menthol application according to the amount of surface area on physiological and psychological heat strains, along with body regional influences. Male students underwent two stages of experiments: [Experiment 1] Cutaneous thermal threshold test at rest on eight body regions with/without a 0.8% menthol application at T (a) 28°C and 50% RH; [Experiment 2] Six exercise tests with/without a 0.8% menthol spray at T (a) 28°C and 40% RH, while wearing firefighter's protective clothing (No menthol, PC(NO); Face and neck menthol, PC(FN); Upper body menthol, PC(UP); Whole body menthol application, PC(WB)) or wearing normal clothing (No menthol, NC(NO); Upper body menthol, NC(UP)). Experiment 1 showed that menthol caused no significant influence on cutaneous warm thresholds, while menthol applications evoked earlier detection of cool sensations, especially on the chest (P = 0.043). Experiment 2 revealed that NC(UP), PC(UP) and PC(WB) caused lower mean skin temperature, especially with higher peripheral vasoconstrictions on the extremities at rest. During exercise, NC(UP), PC(UP) and PC(WB) induced greater and earlier increases in rectal temperatures (T (re)) and a delayed sweat response, but lessened psychological burdens (P < 0.05). Both physiological and psychological effects of PC(FN) were insignificant. For a composite analysis, individual Menthol Sensitivity Index at cooling in Experiment 1 had significant relationships with the threshold for T (re) increase and changes in heart rate in NC(UP) of Experiment 2 (P < 0.05). Our results indicate that menthol's topical influence is body region-dependent, as well as depending on the exposed body surface area.
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Cheuvront SN, Kenefick RW, Montain SJ, Sawka MN. Mechanisms of aerobic performance impairment with heat stress and dehydration. J Appl Physiol (1985) 2010; 109:1989-95. [DOI: 10.1152/japplphysiol.00367.2010] [Citation(s) in RCA: 284] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Environmental heat stress can challenge the limits of human cardiovascular and temperature regulation, body fluid balance, and thus aerobic performance. This minireview proposes that the cardiovascular adjustments accompanying high skin temperatures (Tsk), alone or in combination with high core body temperatures (Tc), provide a primary explanation for impaired aerobic exercise performance in warm-hot environments. The independent (Tsk) and combined (Tsk + Tc) effects of hyperthermia reduce maximal oxygen uptake (V̇o2max), which leads to higher relative exercise intensity and an exponential decline in aerobic performance at any given exercise workload. Greater relative exercise intensity increases cardiovascular strain, which is a prominent mediator of rated perceived exertion. As a consequence, incremental or constant-rate exercise is more difficult to sustain (earlier fatigue) or requires a slowing of self-paced exercise to achieve a similar sensation of effort. It is proposed that high Tsk and Tc impair aerobic performance in tandem primarily through elevated cardiovascular strain, rather than a deterioration in central nervous system (CNS) function or skeletal muscle metabolism. Evaporative sweating is the principal means of heat loss in warm-hot environments where sweat losses frequently exceed fluid intakes. When dehydration exceeds 3% of total body water (2% of body mass) then aerobic performance is consistently impaired independent and additive to heat stress. Dehydration augments hyperthermia and plasma volume reductions, which combine to accentuate cardiovascular strain and reduce V̇o2max. Importantly, the negative performance consequences of dehydration worsen as Tsk increases.
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Affiliation(s)
- Samuel N. Cheuvront
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Robert W. Kenefick
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Scott J. Montain
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Michael N. Sawka
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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Exercise, Heat Stress and the Interleukin-6 Response: Support for Temperature-Mediated Neuroendocrine Regulatory Mechanisms. ACTA ACUST UNITED AC 2010. [DOI: 10.2478/v10036-010-0018-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Burdon C, O'Connor H, Gifford J, Shirreffs S, Chapman P, Johnson N. Effect of drink temperature on core temperature and endurance cycling performance in warm, humid conditions. J Sports Sci 2010; 28:1147-56. [DOI: 10.1080/02640414.2010.489197] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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