Fluid balance test

The goal is to see exactly how much dehydration you incur during your workout. Don't try anything new just yet. Make sure that you are in good physical condition or check with your doctor.


  1. Empty you bladder and record you weight (nude or swim suit)

    pre-exercise weight = ___________ lbs.(A)

  2. Do your usual workout, and drink like your normally would.
  3. Record the approximate volume of fluid consumed during exercise.

    How much you drank = ___________ fluid ounces

  4. Towel dry, empty your bladder and then record your weight (nude or swim suit)

    post-exercise weight = ___________ lbs.(B)

  5. Subtract your post-exercise weight from your pre-exercise weight to get the number of pounds you lost during exercise.

    weight lost = _____lbs.(A) - ______lbs(B) = ________lbs.(C)

  6. To find out how many fluid ounces of water you have lost, multiply pounds x 15.3

    _____lbs(C) x 15.3 = ________ fluid ounces of water you lost during exercise

  7. To find out what percentage of your weight you lost during exercise,

    _____lbs. (C)

    ________________ X 100 = ________ % Body weight lost

    _______lbs. (A)

The following table and graph relate % body weight loss to performance and symptoms.

Relating % loss of body weight to symptoms and performance in the heat

from Nutrition for Cyclists, Grandjean&Ruud, Clinics in Sports Med. Vol 13(1);235-246. Jan 1994

last update 12/97