

How to Calculate Your Sweat Rate
- Weigh yourself immediately before your run.
- Keep track of your fluid intake during your run.
- Weigh yourself immediately after your run.
- Calculate your sweat rate using this formula: pre-run weight in ounces – post-run weight in ounces + fluid intake in ounces during your run = your sweat rate
- Just in case you forgot, 1 pound = 16 ounces
Example:
- Pre-run weight = 140 x 16 = 2,240
- Fluid intake during run = 16 ounces
- Post Run Weight = 139 x 16 = 2,224
2,240-2,224 = 16 oz + 16 oz = 32 oz or 2 pounds of sweat loss
How to Improve Your Hydration Levels
- 30 minutes before your run: Drink 8-16 ounces of water.
- During your run: Try to consume 16 ounces of water for every hour you are running.
- After your run: Drink water until your urine is pale.
- Daily: Drink enough water to keep hydrated and urine pale.
A small amount of dehydration will not have a negative impact on your performance, but if you sway too far and become overly dehydrated or overly hydrated you may see a decline in performance as well as experience serious medical conditions.
Impaired performance begins when you’ve lost around 3% of your body weight from sweat.
Check-in
Take a picture before, during or after your longest run this week post it to twitter or instagram along with your sweat rate and include the hashtag #RacePaceRunner @racepacejess.
Great post! When I go for long runs I typically will bring a water bottle and an energy gel (I like the espresso ones). I usually start to drink water at the 5 mile mark, and take energy gel every five-ish miles. I do find that after runs that are 10+ miles, I am super dehydrated for the rest of the day, so it is helpful to know how to make sure I am staying hydrated. Is there a way to know my sweat rate without a scale? How important is knowing your sweat rate, can I simply just drink a lot of water to combat the rate that I sweat?