Seems only right to write about a topic at a time when the fall seasons are about to begin. Hydration is very important for not only performance on the field but also just being able to live. We are made up of 60% water and it is essential for many reactions in our bodies and for us to function efficiently.
Why are liquids important?
Water is essential to maintain blood volume, regulate body temperature and allow muscle contractions to take place. During exercise, the main way the body maintains optimal body temperature is by sweating. Sweat production, and therefore fluid loss, increases with a rise in ambient temperature and humidity, as well as with an increase in exercise intensity.
Drinking fluid during exercise is necessary to replace fluids lost in sweat. This action will reduce the risk of heat stress, maintain normal muscle function, and prevent performance decreases due to dehydration.
Dehydration and Performance
As dehydration increases, there is a gradual reduction in physical and mental performance. Studies show that loss of fluid equal to 2% of body mass is sufficient to cause a detectable decrease in performance. Dehydration of greater than 2% loss of body weight increases the risk of nausea, vomiting, diarrhoea, and other gastro-intestinal problems during exercise.
How to estimate fluid loss
Knowing your sweat rate can give you an indication of how much you should be drinking during exercise. Use the tips below to guide:
- Weigh yourself in minimal clothing, as close to the start of exercise as possible. Ideally you should empty your bladder before weighing.
- Weigh yourself at the end of your session, in minimal clothing again, ensuring you towel off any excess sweat from your body.
- Your weight change during exercise reflects your total fluid loss; i.e. the difference between your sweat losses and fluid intake
- Remember that weight loss during exercise is primarily water loss (not fat loss), and needs to be replaced soon after finishing exercise.
How much to replace?
Drinking fluids during exercise helps to prevent a drop in performance caused by dehydration, and fluid after exercise will re-hydrate you. Here are tips to help make sure you are hydrate for your sport or workout:
- Always start exercise well hydrated; this will lower the risk of becoming dehydrated during sport
- Develop a plan for drinking during exercise based on your own sweat rates.
- Immediately after exercise, monitor your weight change to estimate your final fluid deficit. During recovery, you will continue to lose fluids through sweating and urine losses, so plan to replace 125-150% of this fluid deficit over the next 2-6 hours. For example, if you lost 1 kg (1000mL), you will need to drink 1250-1500mL to fully re-hydrate. Drink fluids with your recovery snacks and the following meal to achieve this goal.
- Different sports pose different challenges and opportunities for optimal hydration.
What fluids are best?
Plain water alone is an effective drink for fluid replacement, especially in low intensity and short duration sports.
However, if carbohydrate and electrolytes are added to water, as in a sports drink, performance can be enhanced, especially in high intensity and endurance sports.
Carbohydrate in fluid provides a muscle energy source as well as enhancing flavour. This can be one advantage of a sports drinkover plain water.
Electrolytes such as sodium are lost in sweat and need to be replaced during and after prolonged exercise.
Sodium in fluid improves fluid intake as it stimulates the thirst mechanism, promotes both carbohydrate and water uptake in the intestines, and reduces the volume of urine produced post-exercise.
As you can see, it does not matter if you are playing in sport or just working out. Hydration is very important not only for life but also for your performance on the field and mental function.