Water is our life source

The importance of water in general healthy living is evident for all to see, but with so many varying guidelines, it can be difficult to see why water and fluid regulation is important to exercise. Certainly, the recommendations will change depending upon the sport, intensity, duration, environment and the individual, but the support for drinking in sport, particularly in endurance sports is based on Thermoregulation – maintaining an efficient and effective body temperature.

Exercise induced drinking

Exercise results in the production of heat within the body, which if not regulated could cause complications, particularly in the vital organs. The human body manages heat production by sweating. Transporting the exercise generated heat to the extremities and then dealt with through convection, conduction and evaporation; all designed to keep the body at around the normal 37 degrees Celsius. Of course, this sweat response is an individual one and will vary based on individual characteristics, such as genetics, heat acclimatisation, sweat glands and body weight. All of which result in an emphasis for a variety of fluid recommendations.

Sweating could lead to Dehydration

Dehydration as a term is well understood, but for many the consequence and more precisely the bodily response to dehydration is less known. As mentioned, sweating is instigated as a consequence to a rise in body temperature, caused by exercise. If fluid, that is lost as sweat isn’t replaced, dehydration may occur. Internally, dehydration causes a thickening of the blood and ultimately increases heart rate and therefore making exercise harder.   

“Think of it like this. If you were to water your garden, but instead of water you have treacle flowing through your hose pipe. The treacle represents your thicker blood, due to dehydration. What has happened to the flow? It will now be going a lot slower and not covering your garden. Or in the case of your heart, blood isn’t filling the ventricles as quick, so less blood in, per heartbeat. How could you then increase the flow? For your garden that’s easy, just turn the tap up. For your heart, well it will start to beat faster to try and maintain a higher cardiac output and manage the exercise demand.” In fact, for every 1% of body water loss, your heart will beat and extra 5-8 beats per minute. Dehydration is therefore negative to performance and will quicken the onset of fatigue, along with making exercise all the more uncomfortable.

Hydration Recommendations

It’s worth reiterating here that these are general guidelines and individuals need to monitor, assess and refine these guidelines to suit. Drink too much can be as bad as drinking too little. There’s some very interesting work in the world of hydration that hypothesises, a drinking to thirst theory. It’s also worth noting that in the elite endurance performer, all the world’s best times are often achieved with significant levels of dehydration, and finding your balance is the key. In addition, hydration and your hydration strategy needs to account for the exercise modality, intensity, environment, your clothing, duration, your training status, heat acclimatisation, heat tolerance and your genetics. So definitely not, a one sizes fits all, concept.


Hydration Tips

In planning your hydration strategy think about the volume of fluid you will need before, during and after exercise. Think about all the factors such as intensity and duration. Don’t forget the practical things. How are you going to carry all that water?

Here’s a few tips to get you started:

  • Aim to drink at least 2 Litres of fluid per day.
  • Aim to drink 500 ml of fluid 3-4 hours before the start exercising. Check your urine colour, if dark yellow or highly concentrated consume a further 250 ml of fluid.
  • Aim to match your sweat loss with fluid intake during endurance exercise, as a guide drink at least 2-3 sips of your water bottle every 10-15.
  • Aim to maintain a body water loss of less than 2%.
  • Fluid replenishment after running should be 150% of the water lost as sweat. For example, 1 Litre sweat loss would require 1.5 Litres to replenish. This should be consumed over time as opposed to in one go.

It’s not just about water and we need to also talk about your electrolyte balance, changes in your body salts. It’s also worth mentioning that many of your daily food and drinks contain water, but by going over and above will really help. Regular trips to the bathroom will soon let you know when you are drinking too much and tailor it back from there. Hydration is vital for living, it must therefore be equally as important for exercise performance. Now, go and have a glass of water!