Guest Blog: Linda Samuels

“To Drink or Not to Drink – Is That Your Question?”

The summer sun has amped up the heat and athletes are increasing the volume/intensity of their workouts.  You’ve been sweating a lot more lately, right?  So, it’s time to re-examine your hydration needs!

Exercise and Fluid Replacement

The American College of Sports Medicine (ACSM), developed a Position Statement on Exercise and Fluid Replacement to help guide athletes on some basic hydration goals:

  1. Start exercise in a well hydrated state and with normal electrolyte levels.
  2. The goal of drinking during exercise is to prevent excessive dehydration (weight loss due to sweat losses), and excessive changes in electrolyte balance.
  3. After exercise, the goal is to replace fluid and electrolyte losses.

This all sounds very logical, but how do you actually accomplish these goals?


Research has shown that 89% of athletes start their exercise sessions hypo-hydrated. This means they haven’t been drinking adequately throughout the day, and are already mildly dehydrated.  One way to prevent this is to pay attention to your fluid intake from the time you wake up each day.  Some guidelines suggest that an athlete can divide their weight by 2 or 3, and that’s the number of ounces of fluid they should drink outside of exercise (which is a different calculation).  An example calculation for a 150 lb athlete is 150 ÷ 3 = 50 oz or just over 6 cups of fluid.  To put into practice:

  1.  Upon waking, drink first cup of water
  2. Breakfast, drink another cup
  3. Between breakfast and lunch, another cup
  4. Lunch, another cup
  5. Two hours prior to exercise, drink 2 cups

In hotter/humid environments, you would need to increase your fluid intake even more.

Drink During Exercise

The second goal is to “drink during exercise to prevent excessive dehydration”.  Due to variability of individuals’ sweat loss from the effects of heat/humidity/intensity/duration of exercise, a Sweat Rate Test can provide information so that customized hydration plans can be developed.  Drinking a few sips of sport drink every few minutes will allow an athlete to tolerate the volume necessary to meet their needs. Example:  Sweat Rate of 24 oz/hr:  Drinking 3-4 oz of sport drink every 10 minutes would meet their needs. If an athlete’s sweat rate is higher than 32 oz/hr, I recommend they work with a sports dietitian to dial in their fluid and electrolyte needs. To learn how to complete a Sweat Rate Test, click here.

Finally, is it realistic to weigh in/out of every exercise session to know your fluid replacement needs?  Probably not.  What you can do is complete and record Sweat Rate Tests in numerous temperature ranges (70/75/80/85 degrees, etc).  That way, you’ll generally know how much you will need to take in during exercise, so your end of session fluid replacement would be much less.

My next blog post will dig deeper into an athlete’s electrolyte needs.  Come back and visit, because Training Starts at the Table!



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