Fluid replacement in sport and exercise--a consensus statement.

Maughan, Ron; Goodburn, R; Griffin, Jane; Irani, Mike; Kirwan, J P; Leiper, J. B.; MacLaren, Donald; McLatchie, Greg; Tsintsas, K; Williams, Cicely D.

doi:10.1136/bjsm.27.1.34

“…Increased muscle glucose uptake also occurs under these conditions, favouring glycogen storage. Meanwhile, the serum insulin concentrations returned to basal levels before R2 in both trials in the present study, even though it was suggested that at least a 4 h fast is needed for insulin levels to return to the basal values found after an overnight fast [17] . Complete rehydration was achieved after the 4 h recovery in both trials.…”

Section: Discussioncontrasting

confidence: 45%

“…The investigator responsible for data collection was also kept blind to the order of treatment. During the recovery, the subjects also consumed a volume of water equal to 150 % of their fl uid loss during R1 [17,20,32] . The water was ingested at 30 min intervals throughout the fi rst three hours of the recovery in equivolumetric measures.…”

Section: Experimental Protocolmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Glycemic Index Meals on Recovery and Subsequent Endurance Capacity

Wong¹,

Chen²,

Fung³

et al. 2009

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This study examined the effect of ingesting a high or low glycemic index (GI) meal during a short-term recovery period on endurance running capacity. On two occasions, seven men (age 30.0+/-2.6 yr, body mass 60.7+/-1.4 kg, VO (2max) 62.1+/-2.2 ml.kg (-1).min (-1)) ran at 70% VO (2max) on a level treadmill for 90 min (R1), followed by a 4 h recovery (REC) and a further exhaustive run at the same speed (R2). Twenty minutes after R1, each subject consumed an isoenergetic meal containing either high GI (HGI, GI=77) or low GI (LGI, GI=37) carbohydrate providing 1.5 g CHO.kg (-1) BM. During REC, subjects also ingested a prescribed volume of water equal to 150% of their BM loss during R1. The duration of R2 in the HGI trial was 15% longer than in the LGI trial (HGI: 86.6+/-10.7 min vs. LGI: 75.2+/-8.1 min, p<0.05). The subjects also achieved complete rehydration after REC on both occasions. In conclusion, the consumption of a HGI meal during a 4 h recovery improved endurance capacity in a subsequent run; however, the precise mechanism(s) by which this takes place is yet to be clarified.

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“…In the 1980s, the observation that the addition of carbohydrate to water temporarily slowed gastric emptying rate was interpreted to suggest that fluid replacement solutions should not contain much carbohydrate (Coyle et al, 1978). It is now understood that the slight slowing of gastric emptying caused by solutions containing up to 8% carbohydrate is a relatively minor factor in fluid replacement rate compared with the large influence of increased fluid volume for increasing gastric emptying and fluid replacement rate (Maughan, 1991;Maughan and Noakes, 1991;Coyle and Montain, 1992a,b;Maughan et al, 1993). It was also thought, albeit mistakenly, that 'ingested glucose contributes very little to the total energy utilized during exercise' (Costill and Miller, 1980).…”

Section: Background With Prolonged Continuous Exercisementioning

confidence: 99%

Fluid and fuel intake during exercise

Coyle¹

2004

Journal of Sports Sciences

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The amounts of water, carbohydrate and salt that athletes are advised to ingest during exercise are based upon their effectiveness in attenuating both fatigue as well as illness due to hyperthermia, dehydration or hyperhydration. When possible, fluid should be ingested at rates that most closely match sweating rate. When that is not possible or practical or sufficiently ergogenic, some athletes might tolerate body water losses amounting to 2% of body weight without significant risk to physical well-being or performance when the environment is cold (e.g. 5-108C) or temperate (e.g. 21-228C). However, when exercising in a hot environment ( 4308C), dehydration by 2% of body weight impairs absolute power production and predisposes individuals to heat injury. Fluid should not be ingested at rates in excess of sweating rate and thus body water and weight should not increase during exercise. Fatigue can be reduced by adding carbohydrate to the fluids consumed so that 30-60 g of rapidly absorbed carbohydrate are ingested throughout each hour of an athletic event. Furthermore, sodium should be included in fluids consumed during exercise lasting longer than 2 h or by individuals during any event that stimulates heavy sodium loss (more than 3-4 g of sodium). Athletes do not benefit by ingesting glycerol, amino acids or alleged precursors of neurotransmitter. Ingestion of other substances during exercise, with the possible exception of caffeine, is discouraged. Athletes will benefit the most by tailoring their individual needs for water, carbohydrate and salt to the specific challenges of their sport, especially considering the environment's impact on sweating and heat stress.Keywords: carbohydrate, dehydration, fatigue, gastrointestinal function, hyperthermia, sodium. IntroductionWhen athletes exercise during training or while competing, it is clear that they sometimes benefit by ingesting various mixtures of water, carbohydrate and electrolytes (Convertino et al., 1996;Casa, 2000). The benefits can be expressed through improved performance and/or reduced physiological stress, on an athlete's cardiovascular, central nervous and muscular systems. Although ample scientific evidence exists to support the general theory for encouraging athletes to consume water, carbohydrate and electrolytes during exercise, the practical recommendations for optimally applying these general theories is not simple. This is due to the quite varied nature of the physical stresses encountered during training and competition for a wide range of sports, as well as the unique rules of each sport regarding the allowance for fluid and fuel intake during competition. Furthermore, variations in the physical intensity, duration and environment, as well as individual characteristics of a given athlete, might alter their optimal rate of water, carbohydrate and salt intake as well as the rate of gastrointestinal absorption and feelings of fullness. This task of developing consensus for general recommendations becomes less daunting when approached systematical...

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“…The question is whether these athletes should attempt full fluid replacement compared with their typical practice of incurring dehydration of approximately 2% or more of body weight (Bangsbo et al, 1991;Maughan, 1991;Maughan et al, 1993;Bangsbo, 1994;Maughan and Leiper, 1994). The situation is not unlike marathon running in terms of whether there is an allowable level of dehydration relative to the environment and the individual athlete and the practical realities involved in drinking large volumes of fluid.…”

Section: Fluid Intake and Performance During Sports And Intermittent mentioning

confidence: 99%

Fluid and fuel intake during exercise

COYLE¹

Food, Nutrition and Sports Performance II

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The amounts of water, carbohydrate and salt that athletes are advised to ingest during exercise are based upon their effectiveness in attenuating both fatigue as well as illness due to hyperthermia, dehydration or hyperhydration. When possible, fluid should be ingested at rates that most closely match sweating rate. When that is not possible or practical or sufficiently ergogenic, some athletes might tolerate body water losses amounting to 2% of body weight without significant risk to physical well-being or performance when the environment is cold (e.g. 5-108C) or temperate (e.g. 21-228C). However, when exercising in a hot environment ( 4308C), dehydration by 2% of body weight impairs absolute power production and predisposes individuals to heat injury. Fluid should not be ingested at rates in excess of sweating rate and thus body water and weight should not increase during exercise. Fatigue can be reduced by adding carbohydrate to the fluids consumed so that 30-60 g of rapidly absorbed carbohydrate are ingested throughout each hour of an athletic event. Furthermore, sodium should be included in fluids consumed during exercise lasting longer than 2 h or by individuals during any event that stimulates heavy sodium loss (more than 3-4 g of sodium). Athletes do not benefit by ingesting glycerol, amino acids or alleged precursors of neurotransmitter. Ingestion of other substances during exercise, with the possible exception of caffeine, is discouraged. Athletes will benefit the most by tailoring their individual needs for water, carbohydrate and salt to the specific challenges of their sport, especially considering the environment's impact on sweating and heat stress.Keywords: carbohydrate, dehydration, fatigue, gastrointestinal function, hyperthermia, sodium. IntroductionWhen athletes exercise during training or while competing, it is clear that they sometimes benefit by ingesting various mixtures of water, carbohydrate and electrolytes (Convertino et al., 1996;Casa, 2000). The benefits can be expressed through improved performance and/or reduced physiological stress, on an athlete's cardiovascular, central nervous and muscular systems. Although ample scientific evidence exists to support the general theory for encouraging athletes to consume water, carbohydrate and electrolytes during exercise, the practical recommendations for optimally applying these general theories is not simple. This is due to the quite varied nature of the physical stresses encountered during training and competition for a wide range of sports, as well as the unique rules of each sport regarding the allowance for fluid and fuel intake during competition. Furthermore, variations in the physical intensity, duration and environment, as well as individual characteristics of a given athlete, might alter their optimal rate of water, carbohydrate and salt intake as well as the rate of gastrointestinal absorption and feelings of fullness. This task of developing consensus for general recommendations becomes less daunting when approached systematical...

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Fluid replacement in sport and exercise--a consensus statement.

Cited by 16 publications

References 1 publication

Effect of Glycemic Index Meals on Recovery and Subsequent Endurance Capacity

Effect of Glycemic Index Meals on Recovery and Subsequent Endurance Capacity

Fluid and fuel intake during exercise

Fluid and fuel intake during exercise

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