How Often should I drink??

How often should I drink?

Balancing ‘thirst’ with reality.

How often have you heard that you should drink at least two liters of water, or 8 glasses (who knows how big) every day? If you are an athlete, you could almost assume that you would, therefore, have to double this. At the turn of the century leading Sports Scientists were recommending up to 1 to 1.5 litres of fluid per hour proclaiming the need to match fluid loss with fluid intake. Much of this advice has been driven by the Powerade, Gatorade, and NutrientWaters of the world who have been able to wield substantial influence through their support of nationally recognized institutions and health authorities. Gatorade even gave us the life lesson; “Your brain may know a lot, but it doesn’t know when it’s thirsty”. How very wrong they are and how potentially dangerous this piece of advice is!

The requirement for hydration during exercise is obvious. During exercise, the body sweats to cool down. This sweat is a combination of water and electrolytes, mainly sodium. With increase sweating, water and sodium move out of cells, causing early intercellular dehydration. However, despite what Gatorade wants you to believe, the body is very smart and very resilient. The hypothalamus, our control center for many vital functions, is immediately triggered and stimulates the sensation of ‘thirst’. By no means do you have to completely match your fluid loss with fluid intake during exercise? You just have to maintain an adequate level of hydration in the cells - a level you will know about due to the 'thirst' sensation. Not responding to thirst (a habit of elite athletes) or going over the top (a habit of mid to back-of-the-pack athletes) with it will result in hyponatremia, or dramatically decreased sodium levels. This can not only be bad for your performance by initiating GI upset, it can be fatal as you are effectively drowning your vital organs. 

Image by Korupt Vision

So how much should I drink?

Professor Tim Noakes recommends simply drinking to ‘thirst’. If that is enough for you, amid all the distractions of a race and the influence of nerves, then go forth! However, if you are an elite athlete who understands the dynamics of a race and the need to omit many bodily sensations or a mid-pack athlete who needs some rules to follow, here is an ‘Updated’ plan.

Consume between 450 – 750 milliliters of fluid every hour. Let ‘thirst’ drive your fluid consumption as much as possible but take into consideration variables that will cause you to need more or less fluid. Four factors that can be assumed as your variables are:
1. The intensity of the activity
2. Duration of the activity
3. Your body mass
4. The temperature you are performing in

Being above or below what YOU regard as normal will mean that you should be at the upper or lower end of these recommendations respectively.

If you still need a clearer, more stringent plan, there are online calculators that use this updated research. An example is the Portman Calculator developed by Dr. Robert Portman. Just please show some restraint. Many online calculators are sponsored by nutritional companies (in Portman’s case it is Accelerade) so do not blame me if you find yourself buying a bunch of unwanted Gels.

Hopefully, this helps to clear up some hydration myths currently floating around. Happy training.