How to Hydrate during Exercise

Oranges, lemons, agave and salt

Ingredients for Citrus Quencher

How hydrated you are during long runs or bike rides can determine if you will thrive or wither during your exercise session.

Exercise causes your body temperature to increase, the extent to which depends on your exercise intensity, exercise duration, the climate, the clothes you are wearing and your metabolic rate.  In order to cool your body and lower your body temperature, your body begins to sweat.  This sweat is made up of water and electrolytes.

Electrolytes, such as sodium, potassium, chloride, magnesium and calcium, are minerals that carry electrical charge, which are essential for regulating fluid balance, muscle contraction, nerve function and acid base balance.

When you are not adequately hydrated when exercising, you become dehydrated.  Exercising in a dehydrated state can impact your performance and/or health in a bad way.

Dehydration can lead to:

  • increased heart rate
  • loss of coordination
  • compromised mental concentration
  • muscle fatigue
  • inability to regulate body temperature
  • heat illness, such as cramps, heat exhaustion or heat stroke
  • decreased energy and athletic performance
  • increased risk of gastrointestinal upset

Don’t rely on your thirst mechanism to determine if you are adequately hydrated;  once you feel thirsty, you may already be dehydrated.

There are two ways you can determine if you are adequately hydrated:

1. Body weight before and after exercise

2. Urine color


1. Body weight before and after exercise

You can determine your sweat loss by weighing yourself before and after exercise.  Weigh yourself in the nude, then subtract your post-training weight from your pre-training weight.

Any weight lost is likely due to fluid losses. The table below can help identify hydration status:

%Body Weight Change

Well Hydrated -1 to +1%
Minimal Dehydration -1 to -3%
Significant Dehydration -3 to -5%
Serious Dehydration -5%

A weight loss of greater than 1% indicates mild dehydration and a weight loss of greater than %5 indicates serious dehydration.  Replenish with about three cups of fluid per pound lost.

2. Urine color

The second, and easiest way to determine if you are adequately hydrated,  is by checking the color of your urine.  A very light color of urine (think lemonade) means you are well hydrated. The darker the urine (think apple juice)  the more dehydrated you are.

On the other hand, an increase in weight means you are over-hydrated.  Drinking too much water can lead to hyponatremia.  Hyponatremia indicates an excess of water in relation to the amount of salt in your body. This can lead to serious medical conditions and even death.

What to drink?

Although water is the first and best choice when hydrating during an exercise session, there are times when a sports drink can be beneficial.  Studies show that when you are exercising at high intensity for 45-75 minutes, small amounts of a sports drink, even a mouth rinse, can improve your exercise performance.  It seems to be only effective then you are exercising in a fasted state, such as an early morning exerciser, when exercising several hours after eating or when you are not getting enough carbohydrates in your diet in general.

For exercise sessions that last 1-2.5 hours, getting 30-60g of carbohydrates per hour, has been found to be beneficial. Choose a sportsdrink with a carbohydrate concentration of 6-8% and sodium of 460 to 690 mg/L. In other words an 8 oz serving or one cup should contain about 15 g carbohydrates and 110-165mg of sodium.

Ultra endurance exercise sessions of >2.5-3hours can benefit from up to 80-90 g carbohydrates per hour.

In addition, recent studies show that a carbohydrate mixture of glucose and fructose increases absorption of carbohydrates and in turn increases performance.

If you prefer fresh natural ingredients or are tired of the same sports drink, try making one yourself.  See my recipe below to help get you started.  The ideal carbohydrate concentration should range from 6-8%.

Citrus Quencher

Makes one quart.


1/4 cup agave syrup

1/4 teaspoon salt

1/4 cup water

1/4 cup orange juice plus 2 tablespoons lemon juice

3 1/2 cups cold water


1. Add ingredients to a large pitcher and stir.  Chill for several hours for most refreshing taste.






  1. Homemade Sports Drink | Uncanny - [...] Ray emailed the following recipe to me, so I thought I’d share it with you. He found it on…

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