Rain, rain don't go away ... Calculating your fluid needs

Interesting, important information about hydrating effectively from last night's workshop. I'd like to share what I learned.

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The following information is copyright 2008 by MV Nutrition, LLC and written by Manuel Villacorta, MS, RD from MV Nutrition

Not everyone needs the same amount of fluids. One size does NOT fit all. Figure out your sweat rate so you can create a fluid plan that meets your needs.

Guidelines for calculating your fluid needs:
Your weight before exercise minus your weight after exercise = pounds lost through insensible losses and sweat.

Insensible losses are the water that passes through the skin and is lost by evaporation, and evaporative water loss from the respiratory tract.

Weighing before exercise:

• no clothing or very little clothing
• do not drink any water after weighing (note: it is ok to drink water before you weigh)
• do not urinate after weighing

Then go and perform 1 hour of vigorous exercise. DO NOT drink any water while training for this hour.

Weighing after exercise

• no clothing
• do not drink any water before weighing
• do not urinate before weighing

For every pound lost you must consume 16 oz of fluid.

For example: A person's weight was 160 pounds before exercise and trains for one hour. After training the scale shows their weight go be 158 pounds. Since 2 pounds were lost and you must consume 16 oz for every pound, this person must consume 32 ounces of fluid per hour of riding.

Written by Manuel Villacorta, MS, RD, CSSD

Registered Dietitian / Board Certified Specialist in Sport Dietetics

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So, I did the test incorrectly, after weighing myself before the exercise I did not follow bullet-item number 3. I was too lazy to remove my entire cycling outfit to re-weigh myself; therefore, I had an incorrect calculation. I'll redo the test next week when I don't have road training. I guess 5 pounds of insensible losses and sweat would be a bit much - heck, that would have meant 80 ounces (over 1/2 a gallon) of fluid per hour of training. Best to do this right.