In the first part of this post I highlighted what hydration is and the effects of hyperhydration and dehydration. The importance of maintaining fluid balance during exercise is essential. However, we looked at how we can just take on lots of water in one go. In the following post I want to talk about how much & when you may take on board fluids.


Pre Exercise Hydration

We have already talked about adding Glycerol to your drink. Unfortunately you may not have any to hand! If that is the case, try these protocols.

Before taking part in exercise try to take in 400-600ml of fluid to promote hydration. This should be drunk at least 2 hours before initiating any exercise. Thus allowing enough time to get rid of excess through excretion. Endurance events or activities with little time to stop and drink may require hyperhydrating (talked about in Part 1). Although water is a good form of fluid consuming a sports drinks can help ensure you stay fully hydrated. Additionally it provides pre- exercise carbohydrates which can give you more energy when taking part in the forthcoming activity.


Hydration During Exercise

During exercise it’s important that you try to consume 150-350ml of fluid for every 15-20 minutes of exercise you do. The more sweat lost during exercise, the more fluid you will need to maintain good levels of hydration. By replacing at least 80-90% of your sweat loss with fluid, it is possible to maintain optimal levels for the events duration.

When performing exercise that lasts less than 30 minutes, you can get away with drinking nothing or only water. Similarly, low intensity activities that are lasting less than an hour may only require water. In contrast, exercise at a high intensity for up to an hour, may require hypotonic or isotonic sports drinks. These provide you with energy as well as fluids. Energy can be provided in the form of carbohydrates.


Post Exercise Hydration

Post exercise, should start as soon as possible. It is vital to replace approximately 1.5 times the fluid that you lose during exercise. However, avoid drinking the entire amount of fluid in one go! This will induce a bloated feeling and the majority of the fluid will not be digested.

To ensure effective rehydration, the fluid should be consumed in small doses over a sustained period. A basic method of working out how much you need to replace, is by weighing yourself before and after exercise. 1 litre of sweat is the equivalent to a 1kg body weight loss. Therefore, a loss of 1 kg in weight requires 1.5 litres of fluid.

Sports drinks are the most effective forms of fluid rehydration as they speed up your recovery after exercise. This is due to the addition of carbohydrates they contained. This carbohydrates help replace glycogen stores lost during exercise. Part 3 of this blog will go into more depth about the different types of sports drinks and there effects on the body.


If you are thinking about Personal Training in Twickenham, you will want to make sure you are hydrated! Optimise your performance and get the most out of each workout.