The Sport Science Program Home Page

Step 2: Rehydrate

As we discussed in the Eat Smarter module, perhaps the most important factor for recovery during or post-workout, is rehydrating. You sweat when you participate in sports or exercise. You sweat in order to remove heat from your body, but water is also consumed within the cell itself. When you break down fuels such as carbohydrates, proteins and fats for energy, your body uses water in the process. Additionally, many of the vitamins the body employs are dissolved in water for transportation and other uses.   

Proper hydration is critical to sports performance. Decreases in hydration can cause decreases in plasma volume (the fluid part of your blood), making it harder for your heart to pump blood. A fluid loss of just 2% has been shown to lower muscle performance by 10-20%, and disturbingly, this decrease in hydration is typical for a 90-minute to 2-hour workout, which you probably complete daily. Decreasing hydration also has a negative impact on cognitive function. This makes hydration critical for sports where decision-making is important.

Finding the right amount of fluid to drink during and after exercise depends on the type and intensity of the workout. In general, you should drink 1 litre of fluid for each kilogram of weight lost during exercise. You should stick to water for any training session lasting up to one hour, and then a sports drinks for training or competition lasting longer than that. However, try to stay away from commercial sports drinks as they have a lot of added sugar. Instead try coconut water or watermelon juice.

Dehydration is cumulative. This means that if you don’t replace the lost fluid, the next time you compete you are going to be further in fluid debt!

Today's POWER-UP: How to monitor your hydration levels

In order to stay properly hydrated, you need to recognize the symptoms of dehydration. Symptoms of dehydration include sluggishness, fatigue, headache, loss of appetite, feeling excessively hot, feeling light headed and nausea. 

You can also monitor your hydration levels by paying attention to the colour of urine. A large amount of light-coloured, diluted urine probably means you are hydrated; dark-coloured, concentrated urine probably means you are dehydrated.