How hydrated you are during exercise can determine if you will thrive or wither during your exercise session.
Exercise causes your body temperature to increase. 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 are essential for regulating fluid balance, muscle contraction, nerve function, and acid-base balance.
When you are not drinking enough during exercise, you can impact your performance and impact your health.
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
There are two ways you can find out if you are adequately hydrated:
1. Body weight before and after exercise
2. Urine color
Body weight before and after exercise
You can find out how much you need to drink by determining how much sweat you have lost during exercise. To find out your sweat loss you weigh yourself before and after exercise. Weigh yourself in the nude, then subtract your post-training weight from your pre-training weight.
Any weight loss is likely due to fluid loss. The table below can help identify the 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. Try not to lose more than 2% of body weight. If you have lost one pound in one hour of exercise you have lost about one pint (16 ounces). The next time you exercise drink at least 8 oz every half hour.
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 when 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 sports drink 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 of carbohydrates and 110-165mg of sodium.
Ultra-endurance exercise sessions of >2.5-3hours can benefit from up to 80-90 g of 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. Click Here for my homemade Citrus Quencher. The ideal carbohydrate concentration should range from 6-8%.