Hydration: How much is enough?

Kristin Lee and Kelly Carroll
Feb 4, 2018
2 min read

Did you know 50-60% of our body mass is made of water? Water consists of 75% of lean body mass. So how much should we be drinking?

Hydration is essential during performance and depends on the rate at which you sweat. The sweat rate depends on…

Body size
Gender
Fitness level
Genetics
Environment (temperature, wind velocity, humidity, etc.)
Intensity and duration of exercise

Why do we need to stay hydrated?

To maintain blood volume and restore fluid loss
To prevent dehydration (2-3 L of water is lost per hour)
To easily transfer nutrients to the body
To regulate body temperature

When to Hydrate?

Hydrate prior, during, and after exercise to replace lost fluids.

Before competition: drink 500 ml 2 hours before competition and another 500 ml 15 minutes prior to competition
During: ¼ a cup per 15-20 minutes during exercise
After competition: 1-1.5 L of fluid needs to be consumed for every 2 pounds lost during exercise

WATER IS #1!

Water is the best option when it comes to hydration. It quenches thirst and replenishes lost fluids. Sports drinks contain carbohydrates (sugars) and electrolytes (usually sodium and potassium). Flavored drinks can enhance palatability and promote fluid replacement, but should be used with caution. They often contain high amounts of sugar.

Tips for Consuming Sports Drinks:

Note the amount of sugars
Consider the duration/intensity of workout and the amount of fluids/electrolytes lost
Dilute your sports drinks with water
Don’t only rely on sports drinks. WATER IS #1!

Signs of Dehydration:

Increased thirst
Increased fatigue/weakness
Increased perception of effort
Flushed skin
Dark colored urine
Increased heart rate and breathing
Impaired cognitive performance (ex: skills and coordination)
Gastrointestinal issues (ex: nausea)
Greater risk of heat illness

Over hydration:

Drinking too much can result in hyponatremia and dilute the blood
Hyponatremia = sodium levels in the blood are too low
Symptoms: nausea, headaches, fatigue, cramps

Rehydration:

Adding a moderate amount of sodium to beverage aids in rehydration
Why rehydrate?
To sustain thirst drive
Promote fluid retention
Restore plasma volume

*Athletes should weigh themselves before and after competition to determine fluid loss.

Recommendations for Drinking:

The American College of Sports Medicine recommends…

Drinking adequate fluids 24-hrs prior to an event
Drink about 500 ml (approx. 17 ounces) of fluid 2 hours before exercise to allow time to excrete excess water
Drink early and at regular intervals
Fluids should be cooler than environment temperature
Drink fluids with glucose and/or electrolytes if competition > 1 hour
Drink fluids with sodium during performance if competition > 1 hour to prevent hyponatremia
**Note: all these recommendations depend on the athlete’s sweat rate