Summer is the perfect time for training.
But extra care is needed to stay hydrated.
There is, perhaps, no better sign of a great workout than sweat. As a runner in the South, nothing gives me more satisfaction than seeing those puddles I leave behind after a hard run. That being said, it is important to remember that the copious amounts of sweat beads that drip off our bodies contain two substances that are vital to performance: water and electrolytes.
If we don’t focus on increasing our intake of these substances before, during, and after training, our performance will surely suffer due to dehydration (and all its adverse effects) and cramping.
Calculating Your Sweat Rate
Before we can dive into a discussion on replenishing our bodies of what is lost in sweat, it is important to first discuss sweat rate. Basically, sweat rate is the amount of sweat (in ounces) that you lose per hour of exercise. The rate in which we sweat is influenced by several factors, including exercise intensity, the temperature of the environment in which we exercise, the heaviness of the clothing that we wear, and even our training status. That being said, although sweat rate is affected by several variables, a good estimate can be calculated by following the steps below:
- Weight before exercise ____lbs – Weight after exercise ____lbs = ____ x 16 oz = __oz
- Amount of fluids consumed during activity = ______oz
- Total fluids used during activity = ______oz
- Duration of activity, in hours = ______hrs.
*If your activity is less than one hour, just divide however many minutes it lasted by sixty
Sweat Rate = _______________ / ________________ = _______oz per hr**
Fluids used during activity / Duration of activity (hrs.)
This calculated sweat rate is extremely important as it represents the amount of fluids you need to drink in order to replace what was lost during exercise!!
Hydrating Before, During, and After a Workout
A great way to prevent dehydration is to be proactive and start drinking those fluids well before exercise!
It is recommended that you get about 0.07 to 0.10 ounces of fluid per pound of body weight prior to exercise.
For example, a 150 pound individual would want to take in about 15 ounces of fluid before his or her workout—basically one bottle of water.
A simple guideline for fluid replacement during exercise—if it is possible to drink during your activity—is to get in anywhere from 6 to 12 ounces of fluids every 15 to 20 minutes. A better estimate would be to look at your sweat rate. For example, someone who sweats 30 ounces during an hour of exercise would want to drink 30 ounces each hour—super simple!
As far as post-workout goes, a great way to assess how the amount of fluids you need to take in is by comparing your weight before and immediately prior to exercise: for every pound that you lose, take in 16 ounces of water (one water bottle). Try to weigh yourself with dry clothes on—sweaty clothes are wet and heavy, making you appear to weigh more.
It may seem nasty but one way I assess my hydration-status is by looking at a urine color chart (pictured below). In fact, as a member of the track and cross country team at the University of South Carolina, I am technically not allowed to practice if my urine is a 7 or an 8 prior to practice!
This chart is a great tool to use both before and after exercise. It’s pretty simple: if your urine falls in categories 1-3, you’re hydrated; if not, you need to chug away!! However, while drinking fluids is great, don’t let your urine get any lighter than 1—this is a sign of over-hydration, which can be just as detrimental as dehydration due to the electrolyte imbalances it causes in the blood. Don’t know what I’m talking about? Keep reading!
Electrolyte Loss and Replenishment
Most of us know that our sweat contains salt. These salts, also termed electrolytes, are essential to performance: electrolyte imbalances in the blood, caused by excessive sweating, often result in fatigue and those dreaded muscle cramps. The two electrolytes we hear the most about in regards to sweat and exercise are sodium and potassium. However, it is a common misconception that potassium intake greatly impacts performance: the amount of potassium lost in sweat is actually highly insignificant when compared to sodium. Depending on how “salty” of a sweater you are, you can be losing anywhere from about 0.5 grams to 2 grams of sodium with every liter (32 ounces) you sweat!
As a general rule of thumb, most sports dietitians recommend that you take in about 1 gram of sodium per hour of exercise (*note: if you are planning on exercising less than an hour, just salt your foods before or after activity to replenish your electrolytes). That being said, those who consider themselves “salty sweaters” (you know who you are!) may want to get closer to 1.5 or even 2 grams of sodium per hour of exercise for replenishment.
Some of my favorite options that I use to get my sodium in during and after exercise include Gatorade® (200 mg per 8 oz) and electrolyte tablets such as Nuun® tablets (1 gram per 3 tablets). Gatorade is an especially great tool because it also contains those fluids that will help you re-hydrate!
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