söndag 19 juni 2011

Vätskebalans igen

Jag läste just ytterligare en artikel om vätskebalans. Den finns här (men kräver att man registrerar sig, vilket dock är gratis).

Texten nyanserar argumenten. Vätskebrist kan vara nedsättande för prestationsförmågan, men det kräver att man har förlorat mycket, mer än 3% av kroppsvikten. Dock kan presetationen gå ner vid runt 3% (drygt två liter i mitt fall). Forskningen är något motsägeslefull och beror på typ av sport. Här är sammanfattningen av artikeln:


Safety – the current evidence suggests that even 3% dehydration for sustained periods doesn’t pose a health risk for athletes; Over-drinking to ensure you lose no fluid at all during training or competition therefore seems unwarranted;

Performance – this is where it gets tricky. 5% dehydration didn’t seem to adversely affect running economy and perceived rates of exertion at 70 and 85% of VO2max (although it did increase levels of circulating stress hormones). However, a more modest 2% dehydration did adversely affect basketball skills; it could be that athletes performing sports where skill is a major factor are more prone to the detrimental effects of relatively mild dehydration;

Power to weight ratio - in sports such as cycling and running, where power to weight ratio is important, the potential benefits of dehydration-induced weight loss could well be outweighed by performance drop – certainly, 3.5% dehydration appears to be detrimental to endurance performance;

Strength and power – dehydration at 3% and 5% seems to increase levels of circulating stress hormones, which is undesirable for any athlete wishing to maintain or build maximum strength and power. There are also implications here for immunity, as exercise-induced stress hormone release is known to be associated with decreased post-exercise immunity.

Det här bekräftar vad jag misstänkte. Då jag slog PR i halvmaran förra månaden, drack jag bara tre klunkar vatten under hela loppet.

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