markus138 skrev:
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> Dum fråga, men är det inte sockret man är ute
> efter?
>
> Har ett minne av att jag läste en artikel i
> någon cykeltidning om sportdrycker. Något av
> stallen som cyklar tour de France exprimenterade
> med olika sockerarter.
> Använde man bara en typ av socker kunde kroppen
> bara ta upp en vis mängd under en timme. Blandade
> man sockerarter så ökades kroppens mottagning
> med mer än 20%. Tror dom pratade om glukos och
> fruktos. Någon som minns bättre.
Fast rent strösocker är inte optimalt som kolhydratkälla, men helt klart, som jag redan skrivit, är en kombination troligtivis det mest optimala tack vare separata transportmekanismer.
Int J Sport Nutr Exerc Metab. 2008 Apr;18(2):179-90. Carbohydrate-supplement form and exercise performance.
Numerous studies have shown that ingesting carbohydrate in the form of a drink can improve exercise performance by maintaining blood glucose levels and sparing endogenous glycogen stores. The effectiveness of carbohydrate gels or jellybeans in improving endurance performance has not been examined. On 4 separate days and 1-2 hr after a standardized meal, 16 male (8; 35.8 +/- 2.5 yr) and female (8; 32.4 +/- 2.4 yr) athletes cycled at 75% VO(2peak) for 80 min followed by a 10-km time trial. Participants consumed isocaloric (0.6 g of carbohydrate per kg per hour) amounts of randomly assigned sports beans, sports drink, gel, or water only, before, during, and after exercise. Blood glucose concentrations were similar at rest between treatments and decreased significantly during exercise with the water trial only. Blood glucose concentrations for all carbohydrate supplements were significantly, p < .05, higher than water during the 80-min exercise bout and during the time trial (5.7 +/- 0.2 mmol/L for sports beans, 5.6 +/- 0.2 mmol/L for sports drink, 5.7 +/- 0.3 mmol/L for gel, and 4.6 +/- 0.3 mmol/L for water). There were no significant differences in blood glucose between carbohydrate treatments. The 10-km time trials using all 3 carbohydrate treatments were significantly faster (17.2 +/- 0.6 min for sports beans, 17.3 +/- 0.6 min for sports drink, and 17.3 +/- 0.6 min for gel) than water (17.8 +/- 0.7 min). All carbohydrate-supplement types were equally effective in maintaining blood glucose levels during exercise and improving exercise performance compared with water only.
Med Sci Sports Exerc. 2008 Jan 11. Superior Endurance Performance with Ingestion of Multiple Transportable Carbohydrates.
The aim of the present study was to investigate the effect of ingesting a glucose plus fructose drink compared with a glucose-only drink (both delivering carbohydrate at a rate of 1.8 g.min) and a water placebo on endurance performance.
Eight male trained cyclists were recruited (age 32 +/- 7 yr, weight 84.4 +/- 6.9 kg, V O2max 64.7 +/- 3.9 mL.kg.min, Wmax 364 +/- 31 W). Subjects ingested either a water placebo (P), a glucose (G)-only beverage (1.8 g.min), or a glucose and fructose (GF) beverage in a 2:1 ratio (1.8 g.min) during 120 min of cycling exercise at 55% Wmax followed by a time trial in which subjects had to complete a set amount of work as quickly as possible (~1 h). Every 15 min, expired gases were analyzed and blood samples were collected.
Ingestion of GF resulted in an 8% quicker time to completion during the time trial (4022 s) compared with G (3641 s) and a 19% improvement compared with W (3367 s). Total carbohydrate (CHO) oxidation was not different between GF (2.54 +/- 0.25 g.min) and G (2.50 g.min), suggesting that GF led to a sparing of endogenous CHO stores, because GF has been shown to have a greater exogenous CHO oxidation than G.
Ingestion of GF led to an 8% improvement in cycling time-trial performance compared with ingestion of G.
