How much water should you really be drinking?

Consuming enough water is a necessity to make sure you keep your body working optimally. Water plays a key role in maintaining cellular fluid balance, which is essential for cells to work efficiently. Allowing ourselves to become dehydrated can have a massive impact on our performance in and out of the in the gym, both physically and mentally.


A loss of greater than 2% of our weight in water can seriously impair exercise performance and even smaller amounts lost during exercise have shown to detrimentally influence immediate performance with the level of performance reduction, and perceptions of fatigue, associated strongly with the level of dehydration1.

The amount of water we require to stay fully hydrated is influenced by the losses that occur on a daily basis. If we don’t drink enough water then our body, through a complex hormonal system, will try to prevent water losses by decreasing the amount of urine we produce… this is why the colour of our urine is a loose indicator of the body’s hydration status2. If we get to a point where our urine is a darker shade of yellow than very diluted orange squash there is every chance that you are becoming dehydrated to the point at which it might impact on your performance.


As I’m sure you are aware, water is lost during exercise through sweat. So one thing we can do is weigh ourselves before and after exercise to determine how much fluid we have to replace. However, this kind of attention to detail is only really important for those who maybe train for long periods, in warm environments and especially when it might not be convenient to take on fluids during exercise/sport.

This is actually pretty simple to do as 1kg of water weighs the same a 1l of water… so if you are 500g down than at the start the training session, then you need at least 500ml of water to top yourself back up. If you are going to do this then obviously being as close to naked as possible would be best as sweat will likely be held in clothing, so this may not always be appropriate!

Another consideration here is the assumption that we were already fully hydrated before we performed exercise! However, if we stick to our urine colour guide as a practical measure, then there’s every chance you are going to be fully hydrated.


For many people thirst is a good enough indicator of when to drink and to stay sufficiently hydrated. If you drink when thirsty, then there is every chance you are drinking enough water. However, for athletes there is the suggestion that if you’ve already hit thirst then you are dehydrated enough to impair performance.

For a ‘normal’ person with a fairly sedentary job, they typically require around 2.5l of water per day. This isn’t just in drinking water and other fluids, food also contributes a good amount, and so most people can ‘get away’ with around 1-1.5l of fluid per day and function at an ok level. However, we aren’t just intent on functioning ‘ok’ we want to function at our very best. This takes us back to making sure we drink when thirsty and ensuring that our urine colour is on the pale side; do this and you will likely be consuming more than enough water to keep your performance levels where you want them to be.


Dehydration may also affect our perception of hunger, so drinking plenty of fluid from this perspective is important when dieting. There is some suggestion that drinking water speeds up metabolism and may aid in fat loss. This is potentially true if you are consistently dehydrated and do not consume much fluids, however if you are drinking plenty of fluid and following basic hydration guidelines then drinking any more than this is not going to have as big an impact as many people think on weight loss from a metabolism point of view3.


In some conditions, such as exercising in hot and humid environments, especially for long periods, then we can lose huge amounts of fluids. In this situation then we not only need to replace fluid losses but also electrolytes as well. Electrolytes are also essential to help to maintain cellular fluid balance and proper function, so may need replacing if a person exercises in these circumstances. It is then that hydration drinks and electrolytes can be important to support performance and promote recovery.

Under normal circumstances most of these electrolytes are replaced in a normal diet, so unless we are exercising in pretty extreme conditions or for very long durations electrolytes are not really required and water is sufficient to make sure we stay hydrated and maintain a normal fluid balance.


Some people really dislike the ‘taste’ (if you can call it that!) of water, but drinking any form of fluid can help ensure you have adequate fluid intake. To promote hydration during a workout then adding amino acid supplements to water can also be a tasty and easy to do this, whilst also providing the body with essential nutrients for recovery and muscle growth.

If you struggle to drink enough water or often ignore your thirst through being on the go, busy or easily distracted, then it is probably a good idea to take a water container or bottle with you at all times so that you have no excuse… this is a really basic but effective habit to get into and will often have a huge impact on improving your concentration levels and performance both at work and in the gym.


1.) Casa et al. (2000) National Athletic Trainers’ Association Position Statement: Fluid Replacement for Athletes. Journal of Athletic Training 35(2):212-224.

2.) Sheriffs (2000) Markers of hydration status. Journal of Sports Medicine and Physical Fitness 40(1):80-84.

3.) Vij and Joshi (2013) Effect of ‘Water Induced Thermogenesis’ on Body Weight, Body Mass Index and Body Composition of Overweight Subjects. Journal of Clinical and Diagnostic Research 7(9):1894-1896.

Did you enjoy this article?

Thank you for your feedback