Current Hydration Guidelines May Well Be Wrong

Picture by richseow from Flickr

We've been told in the past by articles, journals and research scientists that if you lose more than 2 percent of your body weight (through sweating) during endurance exercise/ racing your performance will be affected.

Moreover, advertisements from Sports drinks companies keep harping on the fact the you need to drink up or else you get dehydrated.

However, some recent studies (as well as anecdotal evidence from the world's top distance runners) suggest that it may be possible to lose more than 2 percent of your body weight (from sweating) with little or no loss in your performance.

Research scientists from New Zealand's High Performance department have suggested that previous published dehydration studies were conducted in "relatively windless environments (i.e. wind speed less than 12.9km/h) with participants being aware their hydration status." They stated that such conditions do not simulate real race conditions.

In their own (albeit) small study of 10 cyclists, they found that weight loss of up to 3 percent did not slow down the cyclists nor their power output decrease in a 25 km time trial.

Another study on elite male marathoners examined their drinking behavior during 13 major city marathons. Haile Gebreselassie was found to have lost 9.8 percent (and that's a lot) of his body weight during the 2009 Dubai Marathon and still won in 2:05:29 hrs. All drinking by the elite runners were ad libitum (or at their own time and pleasure).

Granted the above study was done on elite runners. Does that even apply to mere mortals like us? Especially in hot and super humid Singapore.

Here are my own thoughts. From the time I started running cross country as a twelve year old kid, I've noticed that I tend to drink less than my team mates and other competitors. And definitely less than what the Sports drinks companies recommend. In fact I often had a side stitch after drinking. That also deterred me from drinking too much then.

So despite what you've heard or read before, at least give it a try in your next few long bike or run sessions. Try to get through those long sessions drinking as little as you can. You'll be pleasantly surprised that you may not need as much fluid as you think.

References

Beis LY, Wright-Whyte M, et al (2012). Drinking Behaviours Of Elite Male Runners During Marathon Competition. Clin J Sport Med. 22(3): 254-261. DOI: 10.1097/JSM.0b013e31824a55d7.

Wall BA, Watson G et al (2015). Current Hydration Guidelines Are Erroneus: Dehydration Does Not Impair Performance In The Heat. BJSM. 49(16): 1077-1083. http://dx.doi.org/10.1136bjsports-2013-092417.