Staying hydrated with water

Water: some can’t do without it, while others consume it as minimal as possible. This colourless, odourless and tasteless liquid consists of two hydrogen molecules and one oxygen molecule (scientifically known as H2O).

Irrespective of how you feel about water, this liquid is vital for life. Without water, humans can survive only for a few days, as it makes up 75% body weight in infants, and up to 55% in the elderly. Your muscles even consist of 75% water.


Water helps with the following:

  • Balancing and normalising bodily functions, as well as preventing overall dehydration and maintaining electrolyte balance.
  • Flushing out waste and bacteria from your body, through perspiration, urination, and bowel movements. Poor hydration may increase the risk of developing kidney stones in some individuals. Studies have also shown that drinking adequate amounts of water may reduce the risk of urinary tract infections.
  • Regulating your body temperature.
  • Helping your brain function optimally and assisting with cognitive capabilities, while also improving your mood. 
  • Protecting your tissues, organs and spinal cord, and lubricating cushions and joints.
  • Assisting with digestion and nutrient absorption.
  • Maintain weight. Research has shown that having water before a meal may promote weight loss through suppressing your appetite. This was also noted in another study in which diet drinks were swapped for water. The results showed that this may lead to greater reduction in weight.
  • Keeping skin radiant.


It is important to drink water before, during and after exercise. The exact amounts of water needed will vary from individual to individual. The following is only a basic guide:

  • Before: 500 ml to 600 ml of water at least two hours prior exercise
  • During: 200 ml to 300 ml of water for every 10 to 20 minutes of exercise
  • After: 500 ml to 750 ml of water for each 0.5 kg lost due to sweating.

Staying hydrated before training

It can take time for fluids to be absorbed into your body. So, drink at least 500 ml to 600 ml of water before training. After that, drink more if you feel thirsty.

Staying hydrated during training

It is important to drink water during a workout, as dehydration can affect your energy levels.  You can lose up to two litres of fluid an hour through sweating and breathing while exercising. Drinking little and often will give you the best chance of reaching your exercise goals. 

The amount you need to drink will depend on how much you sweat and how long you exercise for. How much you sweat is influenced by your:

  • Size: larger people tend to sweat more than smaller people.
  • Gender: men tend to sweat more than women.
  • Fitness level: fitter people sweat more and earlier in exercise because their bodies are accustomed to needing to cool down.
  • Temperature and environment: the main way the body maintains optimal body temperature during exercise is by sweating. Heat is removed from the body when beads of sweat on the skin evaporate, resulting in a loss of body fluid. Sweat production, and therefore fluid loss, increases with a rise in ambient temperature and humidity.
  • Exercise intensity: you sweat more as you exercise harder.

One way to know when to drink water is to respond to what your body tells you. If you feel thirsty, you really need to drink water as your body is already showing advanced signs that it needs to take in more fluid.

Staying hydrated after training

It is important to hydrate after exercise to make up for all the sweat that you have lost. Consuming at least 250 ml of water within 30 minutes following any exercise will help keep you hydrated. While this is a basic timeline to follow, people with a higher body mass index (BMI) or who sweat more during exercise require more water. The sooner you start to replace the fluid, the sooner you will recover.

Do not be tempted to reward yourself after exercise with a pint or a glass of wine. Alcohol is a diuretic, which means it removes water from your body by increasing how much urine your kidneys produce.


The amount of water you drink each day is important for optimal health. Most people drink when they are thirsty, which helps regulate daily water intake, but this may not be very accurate, more especially when water loss (through sweating and urination) is greater in the body than water replenishment. You will also have to increase your water intake if you are exercising or living in a hotter region to avoid dehydration.

Other ways to assess hydration is through the colour of your urine. Urine that is dark or coloured indicates dehydration. Pale or non-coloured urine typically indicates proper hydration.


Besides exercise, several factors could affect dehydration. The environment can affect how quickly you become dehydrated. Moderate exercise in hot or humid weather can increase the amount of water you need when compared to if you were doing the same activity in an air-conditioned gym. High altitudes can also make your body work harder and affect your hydration levels.

Your general health also affects dehydration. If you are suffering from cold symptoms or getting over an illness, your body likely has lost a good amount of fluids. Conversely, not drinking enough water can make you more prone to getting sick. Maintaining a healthy lifestyle involves a well-balanced diet and regular exercise, and plenty of water, too. 

Finally, travel is a factor that can affect dehydration. Changing climates and time zones can have a negative impact on the body. It is key to maintain your daily water intake, even if your schedule shifts due to travel plans.

Symptoms of Dehydration

Drinking water during all stages of a workout can prevent dehydration. However, if you are starting a new fitness routine or training for a marathon, the amount of water you need may change, and your body may become dehydrated if you are only drinking the right amount of water for the activity alone. There are noticeable changes you will experience if dehydration sets in. Symptoms include:

  • Dry mouth
  • Sleepiness and fatigue
  • Increased thirst
  • Dizziness
  • Decreased urine output or urine that is more yellowish
  • Headache
  • Elevated heart rate
  • Nausea
  • Shortness of breath
  • Heat exhaustion
  • Muscle cramping/fatigue
  • Breakdown of skeletal muscle.

Severe dehydration can also lead to fever, and in some cases, fainting. Even if you do not strictly regulate your water intake on a daily basis, drink as much water as possible, and know what signs to look for to know when you are not getting enough fluids. Every person requires different amounts of water.


As dehydration increases, there is a gradual reduction in physical and mental performance. There is an increase in heart rate and body temperature, and an increased perception of how hard the exercise feels, especially when exercising in the heat. Studies show that a loss of fluid up to 2% of body mass is sufficient to cause a detectable decrease in performance (that is equal to a 1.4 kg loss in a 70 kg athlete). Dehydration of greater than 2% loss of body weight increases the risk of nausea, vomiting, diarrhoea, and other gastro-intestinal problems during exercise. Dehydration reduces the rate of fluid absorption from the intestines, making it more difficult to reverse the fluid deficit. You may end up feeling bloated and sick if you delay fluid replacement.


Here are some tips to keep in mind to prevent dehydration:

  • Don’t wait until you are thirsty! Thirst is one of the early signs of dehydration and if you wait until you are thirsty, you have already started to become dehydrated.
  • Dress for the environment.
    • During warmer months, exercise at the coolest time of the day—such as in the early mornings or late evenings—and wear the lightest clothing that you can (lightweight t-shirts, shorts, low-cut socks).
    • During the colder months, wear several layers of clothing so that you can remove layers as you begin to sweat.
    • Avoid working out in plastic or rubber suits.
  • If you are dehydrated before you start exercising, your core temperature will rise faster and your heart will have to work harder than usual. This will affect your performance negatively and can even lead to heat stroke.


For a lower intensity workout, drink 200 ml to 300 ml of water for every 10 to 30 minutes of exercise. On the other hand, a high-intensity, 90-minute workout calls for closer to 1.6 litres of water or more. 

Adjust your water intake to suit your workout schedule. For example, if you take a 60-minute exercise class, work in at least two or three short water breaks.

Water helps fuel your muscles, so drinking before, during and after exercise will boost your energy levels, and may help to prevent cramps.

Here are some ideas to make sure you drink enough water each day

  • Carry a water bottle filled with water with you wherever you go. This will make it easier to consume enough fluids when you are on the go. It will also remind you of your daily intake.
  • Establish an optimum goal of water intake every day that is within your daily required amount.
  • Pace yourself to approach half of your recommended consumption by midday. It is recommended that you finish your last sip of water about an hour before you go to bed.

To summarise, the detrimental effects of dehydration on performance may include the loss of coordination, an impaired ability to make a decision, an increased rate of perceived exertion and an increased risk of heat stress.

It is therefore essential to manage your sweat rate with fluid intake as closely as possible, and to drink at a rate that is comfortable.


B.M. Popkin., K.E. D’Anci., & I.H. Rosenberg. (2010). Water, Hydration and Health Nutr, 68(8): 439 – 458. Doi: 10.1111/j.1753-4887.2010. 00304.x