Every athlete’s sweat rate is different. Your sweat rate depends on your body size, exercise intensity, climate (temperature, wind, etc.), physical fitness, clothing, gender, and how you acclimated to the current conditions you are exercising in.  

Your sweat rate is the starting point to developing a successful race plan. As you begin to exercise more than an hour, hydration becomes increasingly more important. Hydration has a large role in exercise performance as well as recovery. Maintaining proper hydration levels throughout the day and post exercise can help improve recovery.   If you do not know your sweat rate use the below instructions and equation to determine a estimate of what your fluid loss is. This is a good test to do for athletes who also want to double check their fluid loss in any temperature.   Right now, being winter, it is a good check point to understand what your needs are while exercising outdoors with multiple layers. Same for conditions where you typically may be exercising indoors on a treadmill or trainer. You can compare these test results with those of different climates to monitor fluid needs in varying conditions. This practice helps if you need to make hydration or fueling plan adjustments for your race if weather changes unexpectedly.  

Calculating Your Sweat Rate  

This is a simple way for you to calculate your sweat rate. To begin, record your nude body weight prior to exercise. When you are finished exercising, dry yourself off the best you can and record your nude bodyweight again. Record what and how much you consumed of fluids during your exercise. Subtract your pre-exercise weight from your post-exercise weight and add the amount of fluid you consumed to that number. This will give you the amount of fluid you lost while exercising. Then, you need to divide that number by the amount of hours you exercised, and that will equal your sweat rate. Be sure to record the weather conditions as well. This will help you determine how your sweat rate fluctuates in different temperature ranges.  

Use the list below to calculate your sweat rate.  

1. ________ Record your nude body weight prior to exercise.

2. ________ Record your nude body weight (dry off best you can before recording weight) after exercise (convert weights to ounces; 1 lb = 16 oz).

3. ________ Record how much fluid you consumed during exercise (use ounces).

4. ________ Subtract lines 1 & 2 from above for total weight loss and add line 3. This is the amount of fluid your body lost while exercising.

5. ________ Take the number from line 4 and divide it by how many hours you exercised for.

This will give you an idea of what your sweat rate is.      

Nick Suffredin is an expert in fueling strategies for athletes, and we are proud he is a resource for D3 athletes. Nick Suffredin is a former scientists at the Gatorade Sports Science Institute (GSSI) where his primary responsibility was to support the GSSI physiology research program. As part of the innovation team, Nick supported research to help improve athlete recovery and performance.

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