Hydration in Bodybuilding

Water is crucial for us to remain healthy and alive, but all too often it is taken for granted as to why it is so important and to what extent it helps us perform better in exercise. Water is the second most important element to life next to oxygen. The body can survive for weeks without food but merely days with out water, and often for a lot less in warm temperatures and high altitudes. The body and all its organs are comprised mainly of water making the average person about 60-75% water.

Bodybuilding drinking water during workout

Water is essential to all bodily functions. It aids our digestive system with the absorption of nutrients, it’s involved in the regulation of body temperature and blood circulation, it helps in the transport of nutrients and oxygen to cells and removes waste products from the body. Alongside these functions water also helps to reduce wear on joints providing lubrication and cushioning, including the spinal cord. Without sufficient water supply (dehydration) we open up our bodies to all kinds of problems. Dr. Fereydoon Batmanghelidj et al noted in the book Your Body’s Many Cries for Water that dehydration can lead to hypertension, asthma, allergies and migraines.

Why is water so important for bodybuilding?

The main function of water is its role in temperature regulation. We generate heat when we train and there are numerous mechanisms which the body calls upon to lose heat. Obviously the surrounding environment plays a role, but a significant method of cooling is sweating: The evaporation of fluid from the skin is very effective. During prolonged exercise it is possible to lose as much as two litres of sweat per hour. This would be ideal in keeping us cool, but unfortunately not all sweat evaporates, as some drops off the skin and is wasted.

Losses of fluid corresponding to as little as 2% of body weight can seriously impair the capacity to perform muscular work. In temperate climates, most athletes lose 1-5% of body weight in prolonged exercise, even when taking regular fluid throughout. In extreme conditions, losses of 8-10% have been reported. In severe dehydration and electrolyte loss, a reduction in blood plasma volume can occur, which could result in circulatory failure.

Water transports oxygen, nutrients, hormones and antibodies through the blood stream and lymphatic system (used to fight cancer, viruses, bacteria and infections). This is obviously important to us as we push our bodies hard in the gym and by doing so we greatly increase the amount of water that our body excretes. When we are dehydrated our immune system is therefore open to invasion from outside entities and we are more susceptible to the attack. Thus good hydration helps to protect us from this.

Brain tissue is 85% water and it uses a twentieth of the body’s blood supply. When you are dehydrated you have less water in the blood and this lack of water can reduce brain functions and can cause fatigue, depression, stress and can also lead to migraines which may be also be an indicator or poor body temperature regulation.

Muscle is 75% water, so it is important that a high water level is maintained in order to prevent muscular dehydration. When muscles become dehydrated they are open to possible loss of strength and cramps. Cramps are a muscle spasm where a muscle contracts abnormally and locks into an awkward position. Although the direct cause of cramp remains unknown, it is known that muscles that are over-worked, injured or exposed to extreme temperatures are more likely to succumb to cramp. Water helps to regulate our body temperature and aids in the transport of nutrients to cells, so by increasing water intake we can reduce the risk of cramp.

Water is a lubricant for the joints and the cartilage between the vertebrae and at the end of long bones at synovial joints there is also a significant amount of water. Cartilage needs to be well hydrated as this prevents abrasive damage occurring when the opposing surfaces of the cartilage make contact with each other. Long term inadequately hydrated joints can lead to friction damage resulting in joint deterioration and pain.

Another reason that water is also important to bodybuilders is due to the fact that when we dehydrate, our body’s solution loses viscosity, which, in turn, reduces the efficiency of the protein and enzyme functions of the body. So when we are trying to increase our protein absorption water is a fundamental aspect as acids and enzymes in the stomach break food down into a more fluid state as part of the digestion process. Lack of fluid means you will not be able to break down the food easily and efficiently.

Water is also essential to us as it is fundamental with regards to strength. Being slightly dehydrated will reduce a muscles lifting capability, and training when in this state will reduce strength gains that you might normally get. If you can’t lift as much as when you are adequately hydrated, then how can you expect to push harder and make gains?

Water can be one of your most useful tools for weight loss. Water is calorie free. When you are on a restricted diet, by drinking water you can fill yourself up and alleviate some of the hunger.

How do you know if you are drinking adequate an amount?

The problem lies in how we know if we are well hydrated? The body will lose nearly 6 pints of water per day under average conditions. Most water is lost through urine and this is the best way to gauge your level of hydration. By checking the quantity and colour of your urine you can roughly measure how well hydrated you are. When your urine is dark and produced in small quantities you know you are dehydrated.

The sensation of thirst is your body’s way of telling you that you are already dehydrated, it is not a reliable indicator of hydration state. By the time this sign emerges it is too late as some damage may have been caused. Also in some people thirst appears thirst through habit, e.g. if you are due a coffee break at work, at other times you may not feel thirsty, even though hydration is suboptimal. By keeping your fluid intake regular and at sufficient levels you will notice that your urine will be virtually colourless and in greater quantities. This is the ideal state to be in.

The kidneys need a large water supply as they remove waste products such as uric acid, urea and lactic acid. The colour of your urine is partly due to the level of urea that is present in your urine. Urea is a bi-product of protein synthesis and, as bodybuilders generally eat a high protein diet, our natural urea levels will be higher than that of an individual following a ‘normal’ diet. It is therefore a good idea to make sure water intake is adjusted to compensate for this extra burden.

In practice therefore, you should get used to drinking plenty of water and/or other fluids throughout the day, even when you do not feel thirsty.

Other factors affecting hydration

The main limitation to fluid replacement, is not merely how much you can drink, but how quickly the drink can leave the stomach (Wootton 1988). This is known as the rate of gastric emptying and is influenced by:

  • How much you drink
  • The temperature of the drink
  • How hard you are exercising
  • Current hydration state of the body
  • How much water is in the stomach
  • Relative concentration of electrolytes in the fluid
  • Relative concentration of carbohydrate in the fluid (less an effect, but does significantly affect the rate of fluid absorption directly)

Although larger volumes, up to 600ml, are emptied from the stomach more rapidly than smaller portions, it is generally more uncomfortable to exercise with too much fluid in the stomach. It may cause nausea and reflux, or may interfere with breathing. It is generally better to drink little and often, but how much and how often depends on the individual. Sip water during training, as it feels comfortable.

Colder solutions empty form the stomach more rapidly than warm ones. A cup of tea or coffee during your workout lies on your stomach more, and hot drinks pre workout are a big no-no. Optimum water temperature during exercise is 8 – 13°C, but it is better to have a drink too cold than too warm. Don’t worry about over-chilling the stomach, as cramps are more likely to occur as a result of an over-concentrated solution than from a cold drink. There is also psychological relief from drinking lovely cold water during a hard training session, especially on a hot day – this is therefore advantageous!

Exercise duration has little effect on the rate of gastric emptying, but exercise intensity is very important. The harder you are working, the more difficult it is to replace fluids lost as sweat. Remember, though, that bodybuilding is a train-rest pastime, i.e. during a workout, you may do a very ferocious and intense set, but then you rest for a couple of minutes. This helps gastric emptying, and explains why during weight training we do not need as much water as when we are doing cardio session.

Fluids containing electrolytes at optimum rations can be of use during and after training, they do not replenish lost electrolytes, but do help the rate of gastric emptying and the absorption of water in the intestine. Also small amounts of carbohydrate in water will speed up the rate of gastric emptying, and benefit hydration after exercise.

How much should a bodybuilder drink?

The 6 pints of water loss per day previously mentioned is based on an average person’s activity. Bodybuilders are far more active physically and many of us are also bigger than average people, thus our bodies will lose a much greater percentage of fluid through perspiration. With this in mind it is a good idea to break your daily intake down and try to follow some guidelines as to when and why to drink water.

  1. First thing in the morning is essential as over night your body will lose water and this needs to be replaced. It will also help to aid your digestive system at breakfast. Have at least a cup of fluid before or during breakfast.
  2. Before a meal. It is also a good idea to consume fluid 30-45 minutes before a meal again to increase the efficiency of your digestive system.
  3. During the day it is advisable to consume a cup every hour. This will maintain a constant level of fluid in your system and help to keep your hunger at bay.
  4. Before a workout. Somewhere around 250 – 500 ml of fluid about twenty minutes before training is roughly optimal. This is not too much fluid taken too soon before exercise to make you feel bloated, but sufficient in order to keep you well hydrated for an intense workout.
  5. During training. Sipping water during training as it feels comfortable will help to keep the body hydrated and increase muscular performance.
  6. Before bed. Although being woken in the night needing the toilet can be annoying, it is a good idea to consume a cup of water before going to sleep to help maintain bodily functions over night.
  7. After alcohol. Alcohol is a diuretic so will increase your body’s excretion. It is recommendable to drink a pint of water before bed (assuming you are coming home from a bar or a club) as a minimum as your body will be highly depleted of water. This will also reduce the severity of a hangover!

One final side note for males: By remaining well hydrated you can actually increase your natural libido by increase alertness and raising energy levels and you can make your private life more enjoyable by being able sustain an erection for longer periods of time (will that make you drink more water??!!).


A diuretic acts to reduce water retention in the body by increasing the rate of excretion of water through the kidneys. Diuretics can be prescribed medically but there are some commonly consumed diuretics. Alcohol and caffeine are two commonly used diuretics. It may take up to 48 hours to fully re-hydrate after a heavy drinking session – so, avoid the booze! Caffeine is a diuretic in larger amounts but a cup or tea or coffee or two will not provide enough caffeine to have any effect on hydration state. Caffeine is very topical in its use in bodybuilding, hence there is an article devoted to it – See Caffeine, Health and Bodybuilding.

Final note

Don’t wipe sweat off during training (unless it’s getting in your eyes), and splashing water on the skin is also a useful way to aid the loss of heat through evaporation. Wear suitable gym clothing, to help keep cool – avoid heavy sweaters and thick training bottoms, just because they make you look bigger!

Photo of author

James Collier

James first started bodybuilding as a teenager back in the 1980s and obtained his degree in Nutrition and Dietetics from the University of Surrey back in 1995. After qualifying he worked as a clinical Dietitian for the NHS in various UK hospitals.

Having competed several times during the 1990s, his passion now lies in helping other bodybuilders, strength and fitness trainees reach their goals.

He is a Registered Nutritionist and a full member of The Nutrition Society in the UK. James is also co-founder and developer of Huel, nutritionally complete food.

As an Amazon Associate we earn from qualifying purchases.