Water has many important roles in the body and is required to maintain blood volume and regulate body temperature. During exercise the body cools itself by sweating but this ultimately results in a loss of body fluid which, if not replaced, can lead to dehydration. Sweat production (fluid loss) increases with increasing temperature and humidity, as well as with an increase in exercise intensity.
Drinking fluid during exercise is necessary to replace the fluid lost through sweat and the amount of fluid consumed should reflect the amount of fluid lost through sweat. We have all experienced the headache you get after you finish your netball game! This, my friends, is dehydration. The amount of fluid you lost during the game was more than the amount you consumed – and maybe you were a bit dehydrated to begin with.
As dehydration increases, there is a 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. Impaired skill level can also occur, muscle cramping, along with mental fatigue that can impact concentration and decision making. Dehydration can also increase the risk of nausea, vomiting, diarrhoea and other gastro-intestinal problems during and after exercise.
Chronic dehydration is persistent water deficiency that results in loss of more than 1% of body weight. By definition, dehydration is called chronic if it lasts for more than one day. Being chronically dehydrated can lead to dry skin and other skin problems, thirst, dry mouth, bad breath, dizziness, fatigue, sleepiness, yawning, insomnia, irritability, impatience, bloating, constipation, weight gain, increased or pungent body odour, headache, migraine, anxiety, depression, short attention span, joint stiffness and pain, muscle pain and stiffness, craving sugar and carbs, fast heart rate or palpitations, poor appetite & nausea. You may also notice you have brittle hair, poor circulation, and dark urine.
How much fluid and when?
The amount and timing of fluid depends on each individual’s needs and the rules and regulations of the sport. Different sports have different challenges and opportunities for hydration. Here are some tips to help you with your fluid goals:
Always start exercise hydrated to lower the risk of becoming dehydrated during exercise
Aim for pale-yellow, straw coloured urine as a useful sign of adequate hydration
Avoid drinking excessive amounts of fluid before and during exercise as this can lead to increased urination and gastrointestinal upset (stitches)
You will continue to lose fluids through sweating and urine after you finish exercising. Ensure you rehydrate yourself in the 4-6 hours after you stop exercising
Drink fluids in conjunction with your salty recovery snacks (e.g. cereal, bread, vegemite, milk) to help your body rehydrate more effectively.
What is the best fluid to drink?
As there are many drink options available, it’s important to determine which fluid is best for you. Plain water can be an effective drink for fluid replacement, especially in low intensity and short duration sports. Sports drink can be useful in during some activities, especially high intensity or endurance sports, as it contains both carbohydrate for fuel and flavour and electrolytes (sodium) to help the body retain fluid more effectively as well as stimulate thirst.
Sports drinks are great at what they are designed for, but they do contain a mountain of sugar as well. Electrolyte sachets from the chemist can be a better option if you desire to reduce your sugar intake.
We like to encourage our clients to maintain a good fluid intake. In our colder climate, it can be quite hard to keep up the daily requirement. Our recommendation it to add some fruit to your drink bottle (blueberries, mint, raspberries, citrus etc.), to keep it interesting. Try to stay away from store-bought fruit juice and cordial.