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Jay O, Périard JD, Clark B, Hunt L, Ren H, Suh H, Gonzalez RR, Sawka MN. Whole body sweat rate prediction: outdoor running and cycling exercise. J Appl Physiol (1985) 2024; 136:1478-1487. [PMID: 38695357 DOI: 10.1152/japplphysiol.00831.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 04/22/2024] [Accepted: 05/01/2024] [Indexed: 06/14/2024] Open
Abstract
Our aim was to develop and validate separate whole body sweat rate prediction equations for moderate to high-intensity outdoor cycling and running, using simple measured or estimated activity and environmental inputs. Across two collection sites in Australia, 182 outdoor running trials and 158 outdoor cycling trials were completed at a wet-bulb globe temperature ranging from ∼15°C to ∼29°C, with ∼60-min whole body sweat rates measured in each trial. Data were randomly separated into model development (running: 120; cycling: 100 trials) and validation groups (running: 62; cycling: 58 trials), enabling proprietary prediction models to be developed and then validated. Running and cycling models were also developed and tested when locally measured environmental conditions were substituted with participants' subjective ratings for black globe temperature, wind speed, and humidity. The mean absolute error for predicted sweating rate was 0.03 and 0.02 L·h-1 for running and cycling models, respectively. The 95% confidence intervals for running (+0.44 and -0.38 L·h-1) and cycling (+0.45 and -0.42 L·h-1) were within acceptable limits for an equivalent change in total body mass over 3 h of ±2%. The individual variance in observed sweating described by the predictive models was 77% and 60% for running and cycling, respectively. Substituting measured environmental variables with subjective assessments of climatic characteristics reduced the variation in observed sweating described by the running model by up to ∼25%, but only by ∼2% for the cycling model. These prediction models are publicly accessible (https://sweatratecalculator.com) and can guide individualized hydration management in advance of outdoor running and cycling.NEW & NOTEWORTHY We report the development and validation of new proprietary whole body sweat rate prediction models for outdoor running and outdoor cycling using simple activity and environmental inputs. Separate sweat rate models were also developed and tested for situations where all four environmental parameters are not available, and some must be subsequently estimated by the user via a simple rating scale. All models are freely accessible through an online calculator: https://sweatratecalculator.com. These models, via the online calculator, will enable individualized hydration management for training or recreational cycling or running in an outdoor environment.
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Affiliation(s)
- Ollie Jay
- Heat and Health Research Center, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Julien D Périard
- Research Institute of Sports and Exercise, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Brad Clark
- Research Institute of Sports and Exercise, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Lindsey Hunt
- Heat and Health Research Center, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Haiyu Ren
- The Coca-Cola Company (USA), Atlanta, Georgia, United States
| | - HyunGyu Suh
- The Coca-Cola Company (USA), Atlanta, Georgia, United States
| | - Richard R Gonzalez
- Gonzalez Advanced Biophysics Associates, Lorenzo, New Mexico, United States
| | - Michael N Sawka
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, United States
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2
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Armstrong LE. Rehydration during Endurance Exercise: Challenges, Research, Options, Methods. Nutrients 2021; 13:887. [PMID: 33803421 PMCID: PMC8001428 DOI: 10.3390/nu13030887] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 01/18/2023] Open
Abstract
During endurance exercise, two problems arise from disturbed fluid-electrolyte balance: dehydration and overhydration. The former involves water and sodium losses in sweat and urine that are incompletely replaced, whereas the latter involves excessive consumption and retention of dilute fluids. When experienced at low levels, both dehydration and overhydration have minor or no performance effects and symptoms of illness, but when experienced at moderate-to-severe levels they degrade exercise performance and/or may lead to hydration-related illnesses including hyponatremia (low serum sodium concentration). Therefore, the present review article presents (a) relevant research observations and consensus statements of professional organizations, (b) 5 rehydration methods in which pre-race planning ranges from no advanced action to determination of sweat rate during a field simulation, and (c) 9 rehydration recommendations that are relevant to endurance activities. With this information, each athlete can select the rehydration method that best allows her/him to achieve a hydration middle ground between dehydration and overhydration, to optimize physical performance, and reduce the risk of illness.
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Affiliation(s)
- Lawrence E Armstrong
- Human Performance Laboratory and Korey Stringer Institute, University of Connecticut, Storrs, CT 06269-1110, USA
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3
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Abed MEF, Deshayes TA, Claveau P, Jeker D, Thénault F, Goulet ED. Impact of Mild Hypohydration on 100 m Front Crawl Performance and Starting Block Peak Force Production in Competitive University-Level Swimmers. Sports (Basel) 2020; 8:sports8100133. [PMID: 33066345 PMCID: PMC7602092 DOI: 10.3390/sports8100133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 11/29/2022] Open
Abstract
Unstructured, ad libitum drinking may predispose some athletes to start exercise already slightly hypohydrated (decreased body water). The impact of pre-exercise mild hypohydration on subsequent swimming performance is still unknown. Hence, the goal of this study was to examine its effect on peak force production on the starting block and 100 m front crawl swimming performance in competitive university-level swimmers. At least one hour after having been passively exposed to heat where a body mass loss of 1.5% was induced or euhydration (normal body water) maintained, nine participants (age: 22 ± 2 years) underwent an assessment of their peak force production on the starting block and 100 m front crawl performance. One hour following hypohydration, rectal temperature had returned to baseline in each condition. Urine osmolality and specific gravity were higher (p < 0.05) with hypohydration than euhydration (995 ± 65 vs. 428 ± 345 mOsmol/kg; 1.027 ± 0.003 vs. 1.016 ± 0.007 g/mL) prior to exercise testing, as was perceived thirst. Swimming performance (p = 0.86) and peak force production (p = 0.72) on the starting block did not differ between the hypohydration and euhydrated condition (63.00 ± 4.26 vs. 63.09 ± 4.52 s; 1322 ± 236 vs. 1315 ± 230 N). The current results indicate that mild hypohydration, which may occur with ad libitum drinking, does not impede peak force production on the starting block and 100 m front crawl performance in university-level competitive swimmers. Planned drinking is not required prior to such an event.
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Affiliation(s)
- Mohamed El Fethi Abed
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - Thomas A. Deshayes
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
- Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC J1H 4C4, Canada
| | - Pascale Claveau
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - David Jeker
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - François Thénault
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - Eric D.B. Goulet
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
- Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC J1H 4C4, Canada
- Correspondence: ; Tel.: +1-819-821-8000 (ext. 62728)
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Sánchez-Molina J, Tronero-Aguilera JF, Clemente-Suárez VJ. Psychophysiological respond in a swimming ultra-endurance event. J Sports Med Phys Fitness 2020; 61:140-145. [PMID: 32693561 DOI: 10.23736/s0022-4707.20.11201-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Ultra-endurance events under critical environmental conditions represent unique stress, resulting in acute marked adaptations to the cardiovascular, respiratory, metabolic and neuromuscular systems of the organism. In line with this, no studies in swimming events were found thus far. METHODS This research aimed to analyze the psychophysiological response of swimmers in an ultra-endurance swimming event. Changes in the rate of perceived exertion, blood lactate concentration, 1000m swimming time and cortical arousal were measured in 19 male volunteer swimmers (28.0±5.6 years; 175.0±7.9 cm; 70.1±7.8 kg) in 3 moments during a 24h swimming event. RESULTS We found a significant increase in lactate concentration after series 1, decreasing the values in series 2 and series 3. Cortical arousal decreased significantly in series 3 respect the basal sample. Rate of perceived exertion significantly increased in the swimming ultra-endurance event and 1000m swimming time was maintained during the series analyzed. CONCLUSIONS An ultra-endurance swimming event produced an increase in blood lactate concentration and rated of perceived exertion and a decrease in cortical arousal, not affecting average swimming velocity along the event.
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Affiliation(s)
| | - José F Tronero-Aguilera
- Faculty of Sports Sciences, European University of Madrid, Madrid, Spain.,Research Center in Applied Combat (CESCA), Toledo, Spain
| | - Vicente J Clemente-Suárez
- Faculty of Sports Sciences, European University of Madrid, Madrid, Spain - .,Research Center in Applied Combat (CESCA), Toledo, Spain.,Grupo de Investigación en Cultura, Educación y Sociedad (CULTEDUSOC), Coast University, Barranquilla, Colombia
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James LJ, Funnell MP, James RM, Mears SA. Does Hypohydration Really Impair Endurance Performance? Methodological Considerations for Interpreting Hydration Research. Sports Med 2020; 49:103-114. [PMID: 31696453 PMCID: PMC6901416 DOI: 10.1007/s40279-019-01188-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The impact of alterations in hydration status on human physiology and performance responses during exercise is one of the oldest research topics in sport and exercise nutrition. This body of work has mainly focussed on the impact of reduced body water stores (i.e. hypohydration) on these outcomes, on the whole demonstrating that hypohydration impairs endurance performance, likely via detrimental effects on a number of physiological functions. However, an important consideration, that has received little attention, is the methods that have traditionally been used to investigate how hypohydration affects exercise outcomes, as those used may confound the results of many studies. There are two main methodological limitations in much of the published literature that perhaps make the results of studies investigating performance outcomes difficult to interpret. First, subjects involved in studies are generally not blinded to the intervention taking place (i.e. they know what their hydration status is), which may introduce expectancy effects. Second, most of the methods used to induce hypohydration are both uncomfortable and unfamiliar to the subjects, meaning that alterations in performance may be caused by this discomfort, rather than hypohydration per se. This review discusses these methodological considerations and provides an overview of the small body of recent work that has attempted to correct some of these methodological issues. On balance, these recent blinded hydration studies suggest hypohydration equivalent to 2–3% body mass decreases endurance cycling performance in the heat, at least when no/little fluid is ingested.
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Affiliation(s)
- Lewis J James
- School of Sport, Exercise and Health Sciences, National Centre for Sport and Exercise Medicine, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
| | - Mark P Funnell
- School of Sport, Exercise and Health Sciences, National Centre for Sport and Exercise Medicine, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Ruth M James
- Sport, Health and Performance Enhancement Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Stephen A Mears
- School of Sport, Exercise and Health Sciences, National Centre for Sport and Exercise Medicine, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
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Buoite Stella A, Yardley J, Francescato MP, Morrison SA. Fluid Intake Habits in Type 1 Diabetes Individuals during Typical Training Bouts. ANNALS OF NUTRITION AND METABOLISM 2018; 73:10-18. [PMID: 29843124 DOI: 10.1159/000489823] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 04/30/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS Hyperglycemia may influence the hydration status in diabetic individuals. During exercise, type 1 diabetes mellitus (T1DM) individuals may be challenged by a higher risk of dehydration due to a combination of fluid losses from sweat and increased urine output via glycosuria. So far, no study has characterised spontaneous fluid intake in T1DM individuals during active trainings. METHODS A validated questionnaire was used to assess T1DM participants' diabetes therapy, sports characteristics and fluid intake during training; results were then compared to an age- and sport-matched sample of non-diabetic individuals. RESULTS Ninety individuals completed the survey (n = 45 T1DM individuals, n = 45 matched controls). A proportion of T1DM -individuals reported blood glucose levels greater than 10.0 mmol at both the start (28.9%) and end (24.4%) of the exercise. The mean self-reported fluid intake was greater in T1DM (0.60 ± 0.47 L·h-1) compared to that of the control (0.37 ± 0.28 L·h-1, p < 0.05). In spite of drinking fluid volumes in line with international guidelines, 84.4% of those with T1DM reported that they were still feeling thirsty at the end of their training session. CONCLUSIONS T1DM individuals self-report spontaneously consuming fluid adequate volumes suggested by sport nutrition guidelines for non-diabetic athletes. Discrepancies in the T1DM subjectively reported feelings of thirst suggest that more education on hydration during exercise is needed for this population to adequately compensate for elevated blood glucose levels. It remains to be established whether fluid volumes suggested for healthy athletes are adequate for maintaining euhydration in T1DM patients due to their altered diuresis.
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Affiliation(s)
- Alex Buoite Stella
- Department of Medicine, University of Udine, Udine, Italy.,Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy
| | - Jane Yardley
- Department of Social Sciences, Augustana Campus, University of Alberta, Edmonton, Alberta, Canada
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Katch RK, Scarneo SE, Adams WM, Armstrong LE, Belval LN, Stamm JM, Casa DJ. Top 10 Research Questions Related to Preventing Sudden Death in Sport and Physical Activity. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2017; 88:251-268. [PMID: 28805553 DOI: 10.1080/02701367.2017.1342201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Participation in organized sport and recreational activities presents an innate risk for serious morbidity and mortality. Although death during sport or physical activity has many causes, advancements in sports medicine and evidence-based standards of care have allowed clinicians to prevent, recognize, and treat potentially fatal injuries more effectively. With the continual progress of research and technology, current standards of care are evolving to enhance patient outcomes. In this article, we provided 10 key questions related to the leading causes and treatment of sudden death in sport and physical activity, where future research will support safer participation for athletes and recreational enthusiasts. The current evidence indicates that most deaths can be avoided when proper strategies are in place to prevent occurrence or provide optimal care.
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8
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Cheuvront SN, Montain SJ. Myths and methodologies: Making sense of exercise mass and water balance. Exp Physiol 2017; 102:1047-1053. [DOI: 10.1113/ep086284] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/01/2017] [Indexed: 11/08/2022]
Affiliation(s)
| | - Scott J. Montain
- US Army Research Institute of Environmental Medicine; Natick MA USA
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Chlíbková D, Nikolaidis PT, Rosemann T, Knechtle B, Bednář J. Reported Hydration Beliefs and Behaviors without Effect on Plasma Sodium in Endurance Athletes. Front Physiol 2017; 8:259. [PMID: 28512433 PMCID: PMC5411442 DOI: 10.3389/fphys.2017.00259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/10/2017] [Indexed: 11/13/2022] Open
Abstract
Purpose: Little information is available on the association of hydration beliefs and behaviors in endurance athletes and exercise-associated hyponatremia (EAH). The aim of the present study was to determine hydration beliefs and behaviors in endurance athletes. Method: A 100 and 38 recreational athletes [107 mountain bikers (MTBers) and 31 runners] competing in seven different endurance and ultra-endurance races completed pre- and post-race questionnaires, and a subgroup of 113 (82%) participants (82 MTBers and 31 runners) also provided their blood samples. Result: More than half of the participants had some pre-race (59%), mid-race (58%), and post-race (55%) drinking plan. However, the participants simultaneously reported that temperature (66%), thirst (52%), and plan (37%) affected their drinking behavior during the race. More experienced (years of active sport: p = 0.002; number of completed races: p < 0.026) and trained (p = 0.024) athletes with better race performance (p = 0.026) showed a more profound knowledge of EAH, nevertheless, this did not influence their planned hydration, reported fluid intake, or post-race plasma sodium. Thirteen (12%) hyponatremic participants did not differ in their hydration beliefs, race behaviors, or reported fluid intake from those without post-race EAH. Compared to MTBers, runners more often reported knowledge of the volumes of drinks offered at fluid stations (p < 0.001) and information on how much to drink pre-race (p < 0.001), yet this was not associated with having a drinking plan (p > 0.05). MTBers with hydration information planned more than other MTBers (p = 0.004). In comparison with runners, more MTBers reported riding with their own fluids (p < 0.001) and planning to drink at fluid stations (p = 0.003). On the whole, hydration information was positively associated with hydration planning (n = 138) (p = 0.003); nevertheless, the actual reported fluid intake did not differ between the group with and without hydration information, or with and without a pre-race drinking plan (p > 0.05). Conclusion: In summary, hydration beliefs and behaviors in the endurance athletes do not appear to affect the development of asymptomatic EAH.
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Affiliation(s)
- Daniela Chlíbková
- Centre of Sports Activities, Brno University of TechnologyBrno, Czechia
| | | | - Thomas Rosemann
- Institute of Primary Care, University of ZurichZurich, Switzerland
| | - Beat Knechtle
- Institute of Primary Care, University of ZurichZurich, Switzerland.,Gesundheitszentrum St. GallenSt. Gallen, Switzerland
| | - Josef Bednář
- Faculty of Mechanical Engineering, Brno University of TechnologyBrno, Czechia
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COUNTERVIEW: Is Drinking to Thirst Adequate to Appropriately Maintain Hydration Status During Prolonged Endurance Exercise? No. Wilderness Environ Med 2016; 27:195-8. [DOI: 10.1016/j.wem.2016.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/09/2016] [Accepted: 03/09/2016] [Indexed: 11/24/2022]
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