Hydration Blog

Sugihara and colleagues have just published online in the European Journal of Applied Physiology (link to paper here) their 8-subject study that looked into the effect of ramping up the sodium content of a drink on hydration status. The hypothesis being that if the athlete is hyperhydrated with a higher sodium drink then performance increases. Or at least performance degradation is slowed. The drinks used were of fairly high sodium content (1380mg/L, 2760mg/L and 4140mg/L) when you consider sea water is around 10,000mg/L, Gatorade is 450mg/L while Powerade stands at 225mg/L.

The results supports previous work that showed the higher sodium drinks induced hyperhydration with an increase in plasma volume and net water gain. But the higher levels of sodium in the drinks also induced diarrhoea and gut upset. Not pleasant if you're competing and in fact defeats the purpose of taking the drinks in the first place. 

What is interesting from our point of view was to see was that the 1380mg/L drink, at 90 min after consumption increased plasma volume compared to water and that the net water gain was maintained at 120 - 150 min after ingestion, without causing excessive gut issues.  So overall it suggests that there is no great need to take sodium in really high quantities, and that using H2Pro Hydrate 1500 (1500mg sodium per litre) as many athletes do to enhance pre-event hydration, should be sufficient.