The Malaysian Formula 1 GP is considered to be the toughest race on the F1 calendar with the heat and humidity taking its toll on the drivers and race crew. Not surprisingly, according to a recent press release Lucozade prepared a special race formulation drink specific to the Mclaren drivers Button and Hamilton http://paddocktalk.com/news/html/story-186284.  Helen Cowie, Technical Director, GlaxoSmithKline Research & Development admits that '....drivers can lose up to three kilos in sweat – roughly five per cent of their body weight......' But  as the drivers are restricted to 1 litre of drink in the cockpit it is imperative that every drop contributes to performance.  

Although the article is based upon science and supports the basis of what we do at Precision Hydration, it fails to mention that Button and Hamilton (and for that matter every single F1 driver on the start grid) have sweat sodium losses that are genetically determined and vary upto 8-fold. Getting this sodium content in the drink is important as sodium is what determines retention of water in the body.  Bespoke hydration in motorsport is not exclusive to Lucozade either as at Precision Hydration we've been doing it since 2009.  In fact our very first client was an endurance rally driver from Kenya who would typically almost pass out on Day 2 or 3 in the heat despite drinking litres of water.  He was tested using the Precision Hydration sweat sodium analysis system and found to be a very high sodium sweater.  With drinking water alone he would dilute his blood sodium leading to water intoxication (mild hyponatraemia).  On bespoke sodium replacement drinks he is now extremely competitive. Since his success our regular clients include Tuthills Porsche Team, David Brabham (ex-F1 and Le Mans winner) and Bradley Smith in Moto2 as well as numerous drivers in GT racing and rallying where the cockpit temperatures can be incredibly high. 

Taken from the Telegraph 26th March 2012:

Since writing this post the following email landed in my inbox. It seems the Consumer Law Group (CLG) have filed a suit against a coconut water company for making claims that it is a good substitute for a sports drink:

Consumer Law Group files lawsuit against Vita Coco

I felt compelled to post this in response to an article I saw entitled:

DITCH THE SPORTS DRINKS: COCONUT WATER IS NATURES WAY TO REHYDRATE.

See http://frugivoremag.com/2012/03/ditch-the-sports-drink-coconut-water-is-natures-way-to-rehydrate/ 

We're seeing coconut water touted as 'natures electrolyte' more and more often I'm really not sure about this! The article does make some valid observations about the high energy/sugar content of some sports drinks not being needed when you are not training hard but the comments on electrolyte balance are not completely accurate.

While coconut water may be natural I'm not convinced that its the best way to hydrate before, during and after exercise.  For very gentle sessions perhaps it might be ok once in a while but I certainly wouldn't be telling anyone to ditch the sports drinks as recommended by the author.  The article does advise against drinking too much to avoid over-hydration and hyponatraemia (low blood sodium) which it admits can be life-threatening (very true).  However, coconut water typically contains only 160mg sodium per litre which is much less than the average sweat sodium losses in humans of around 920 mg per litre so the issue of hyponatraemia is not really avoided by using it.  Then there's the high potassium content (Potassium is not a bad thing in reasonable quantities in protecting against diabetes and high blood pressure) but one litre of coconut water contains over 60% of your daily potassium requirements.  In long hot events if used as a primary hydrator, even with 3 litres the total potassium load will be 1.8 times the daily requirement plus whatever is taken via sports gels and normal food intake. I use Potassium to stop the heart during cardiac surgery so would be extremely hesitant in advising people to drink large volumes of a potassium rich drink when exercising hard or sweating a lot.

The bottom line is that sodium, not potassium, is the key electrolyte you need to replace when sweating and this is summed up nicely with the quote below:

"The only electrolyte added to drinks consumed during exercise that is known to confer physiological benefit is sodium.”

Report of the Scientific Committee on Food on composition and specification of food intended to meet the expenditure of intense muscular effort, especially for sportsmen. 2001. 

Dr Raj Jutley. CMO Precision Hydration ltd.