Thermoregulation, Hydration and Performance over 6 Days of Trail Running in the Tropics

Hue, Olivier; Henri, Stéphane; Baillot, Michelle; Sinnapah, Stéphane; Uzel, A.-P.

doi:10.1055/s-0033-1361186

Cited by 17 publications

(22 citation statements)

References 38 publications

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“…It thus seems clear that these subjects, despite great TBWL (0.5-2.7 L) associated with a mean 0-1.5 L of WI inducing a 0.3-1.3 kg loss (mean 0.4-1.8% of body mass loss), did not present severe dehydration or heat illness while drinking ad libitum as described in the literature in high-level marathoners [10], standard runners [17], and recently in IRP [9]. Taken together, these findings reinforce the view that ad libitum hydration is enough for endurance exercise in a hot environment [17, 21, 22, 23]. These results could be surprising if we consider that average-range athletes normally drink at a higher rate than high-level or more trained ones [24, 25].…”

Section: Discussionsupporting

confidence: 78%

Self-hydration and thermoregulatory processes of average-level paddlers during international surfski events in a tropical climate

Hue¹,

Jeannic²,

Chamari³

2015

Biol Sport

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The aim was to investigate thermal response, hydration behaviour and performance in flatwater kayaking races in tropical conditions (35.9 ± 2.8°C and 64 ± 4% RH). Eight regionally ranked paddlers (ARP) participated in the 2012 Surfski Ocean Racing World Cup in Guadeloupe (an inline 15-km downwind race). Core temperature (Tc) and heart rate (HR) were measured using portable telemetry units, while water intake was deduced from backpack absorption. The kayakers were asked to rate both their comfort sensation and thermal sensation on a scale before and after the race. The performance was not related to any measured parameters, and high values of post-race Tc were related to high pre-race Tc. The present study demonstrated that average-range paddlers are able to perform in a tropical climate, drinking little and paddling at high intensity without any interference from thermal sensations. Core temperature at the end of the race was positively related to pre-race Tc, which reinforces the importance of beginning surfski races with a low Tc and raises the question of pre-cooling strategies for paddlers, and more specifically for those with a low convection body surface.

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Section: Discussionsupporting

confidence: 78%

Self-hydration and thermoregulatory processes of average-level paddlers during international surfski events in a tropical climate

Hue¹,

Jeannic²,

Chamari³

2015

Biol Sport

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“…However, the main factor for heat production is exercise intensity (Racinais et al, 2019) and longer events may be less prone to hyperthermia in a given environment, as they are performed at a lower intensity. For example, a study on 31 heat-acclimated male soldiers participating in a half marathon in tropical environment revealed that 68% of the finishers completed the race with a gastrointestinal temperature > 40 • C (Lee et al, 2010), while in a 142 km trail run performed over 6 days in tropical environment, the maximal gastrointestinal temperature was only 38.3-38.7 • C (Hue et al, 2014). These findings warrant specific field research during ultra-endurance events in hot and humid ambient conditions to characterize the thermal responses to various race situations.…”

Section: Metabolic Heat Production and Core Temperaturementioning

confidence: 99%

Heat Stress Challenges in Marathon vs. Ultra-Endurance Running

Bouscaren

Millet

Racinais

2019

Front. Sports Act. Living

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Several studies have investigated the effect of hot and humid ambient conditions on running exercise up to the marathon. However, studies on exercise longer than marathon are sparse. Events exceeding 6 h can be defined as ultra-endurance and have variable characteristics (e.g., distance, elevation profile, technical difficulty, altitude, night running) making hazardous the transposition of the current knowledge obtained in marathon to ultra-endurance running. Thus, the aim of this manuscript was to discuss the potential differences between marathon and ultra-endurance running in terms of heat stress challenges. The high running intensity (especially for the fastest runners), the urban context with high albedo effect materials, and the hot self-generated microclimate in mass-participation events (especially for the average to slow runners) are specific risk factors associated with marathon running in hot environments. Uphill running/walking (sometimes with poles), exotic destination with long-haul travel, desert environment and the necessity to sustain thermoregulatory and sweating responses for several days are risk factors more specific to ultra-endurance running. These differences call for specific research on the effect of hot ambient conditions in ultra-endurance disciplines to create appropriate recommendations.

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“…Průměrný pozorovaný příjem sledovaných sportovců 0,55 ± 0,34 l/h sice koresponduje s doporučeními ACSM z r. 2007 (0,4-0,8 l/h), ovšem odhadované ztráty tělesné hmotnosti (dehydratace) v rozsahu 6,6-11,7 % 1 v relativně příznivých klimatických podmínkách ~15 °C je zcela mimo "tolerovaný limit 2 %". Nepřímá závislost mezi mírou poklesu hmotnosti a výsledným časem je doložena také u rekreačních maratonských běžců (Zouhal et al, 2010), 6denního horského běžeckého závodu v tropických podmínkách (Hue, Henri, Baillot, Sinnapah, & Uzel, 2014), ale i u kratších běžeckých distancí (11,3 km) (Adams et al, 2016). Uvedené příklady jsou reálným důkazem rozporu mezi teorií a praxí zejména ve vrcholovém sportu.…”

Section: Existuje Hranice Dehydratace Limitující Výkon?unclassified

“…dálkové plavání). Autoři dále konstatují, že dehydratace se pouze minimálně podílí na vzestupu tělesné teploty v průběhu zatížení, s výjimkou vzestupu intragastrické teploty, která sice vzrůstá lineárně s poklesem tělesné hmotnosti, ovšem její potenciální dopady na sportovní výkon nejsou blíže popsány (Hue et al, 2014).…”

Section: Autonomní Příjem Tekutin a Vytrvalostní Výkonunclassified

Příjem tekutin během vytrvalostního zatížení – pít podle pocitu žízně, ano nebo ne?

Kumstát

2019

StS

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AbstraktPři nedostatečném příjmu tekutin, při nadměrných ztrátách vody z těla pocením nebo kombinací obou faktorů dochází u sportovců k dehydrataci. Individuálně řízený příjem tekutin během zatížení založený na znalostech míry pocení je optimální strategií, která umožnuje sportovcům kontrolovat rozsah dehydratace a minimalizuje negativní dopady na sportovní výkon. Současná doporučení jsou však soudobou literaturou podrobena kritice pro přeceňování nežádoucích účinků dehydratace na sportovní výkon. "Benevolentní" strategie příjmu t ekutin během sportovního zatížení regulovaná diktátem žízně prochází renesancí a je podložena dostupnou literaturou. Cílem teoretického sdělení je kritická diskuse dvou kontrastních strategií příjmu tekutin během vytrvalostního zatížení, jejich dopad na rozvoj dehydratace a výkon sportovce. Východiskem diskuse jsou recentní publikace k tématu autonomního a předpisovaného příjmu tekutin ve sportu. Na základě dostupné literatury je možné autonomní model příjmu tekutin považovat za hydratační strategii bránící nežádoucímu vzestupu tělesné hmotnosti během zatížení v délce trvání do 90 min. Autonomní příjem je využitelný zejména u rekreačních sportovních aktivit. Předpisovaný příjem tekutin by měli preferovat především účastníci vytrvalostních závodů s délkou trvání nad 90 min a při vysoké okolní teplotě (>30 °C), dále vrcholoví sportovci během pravidelného vícefázového tréninku. AbstractIn case of insufficient fluid intake, excessive water loss from the body by sweating or a combination of both factors results in dehydration in athletes. Individually controlled fluid intake during exercise based on the knowledge of sweating rate is an optimal strategy that allows athletes to control the extent of dehydration and minimises the negative impact on sports performance. However, current recommendations are criticised by contemporary literature due to the overestimation of the undesirable effects of dehydration on sports performance. The "benevolent" strategy of fluid intake during an exercise, regulated by the dictate of thirst, is being re-evaluated with evidence-based support in the available scientific literature. The theoretical work aims to critically discuss two contrasting strategies of fluid intake during endurance exercise, their impact on the progression of dehydration and on athlete's performance. Recent publications on the topic of autonomous and prescribed fluid intake in the sport were the background for the discussion. Based on the current literature, autonomous drinking behaviour is recommended to majority of athletes participating in an exercise with a duration of < 90 min as it sufficiently prevents from overdrinking. Prescribed drinking regime should be adopted by endurance athletes in hot environments (> 30 °C) when exercise duration exceeds 90 min and by an elite athlete during daily multiple-session training.

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Thermoregulation, Hydration and Performance over 6 Days of Trail Running in the Tropics

Cited by 17 publications

References 38 publications

Self-hydration and thermoregulatory processes of average-level paddlers during international surfski events in a tropical climate

Self-hydration and thermoregulatory processes of average-level paddlers during international surfski events in a tropical climate

Heat Stress Challenges in Marathon vs. Ultra-Endurance Running

Příjem tekutin během vytrvalostního zatížení – pít podle pocitu žízně, ano nebo ne?

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