Last weekend my tri club did a 4 hour spinathon for charity at the local Gold’s. I was on the bike for pretty much the whole 4 hours. During that time, I drank four 17 oz. bottles of water. I weighed myself before and after and I lost 5 pounds. So 5 pounds on the scale, plus 4.25 pounds of water = 9.25 pounds that I lost in 4 hours! I know I sweat a lot, but is that REALLY REALLY a lot?
-Colin
My PR was about 18 lbs in a very hot century, a bit over 5 hours.
Sounds about right. I am a big sweater (not the kind you wear, the wet kind) and I go through 4 24ozers in 4 hours and everytime am about 4 lbs lighter.
Wait till you train where I live ! Daily 30-38C and HIGH humidity. Just walking 200m briskly , you perspire ! I won’t even mention the hydration req’ments. So far I have proven correctly , if you can plan and execute your race hydration/nutrition correctly here ,it isn’t much of a question racing in cooler climates.
This is an excerpt from Friels “Hydrating in the Heat”
“Guidelines for fluid and carbohydrate replacement during exercise: Two hours before exercise drink 16 to 24 ounces. Fifteen minutes before exercise drink another eight to 16 ounces. During exercise take in four to 12 ounces every 15 minutes depending on your size and the intensity of the exercise. For exercise lasting longer than one hour use a carbohydrate replacement drink such as Gatorade or PowerAde. To enhance absorption drink larger amounts less frequently rather than small amounts.”
If you follwed this advice you would have drunk 24 before, and an additional 48 per hour = 192. For a total of 216 oz. or 13.5 pounds. Doesn’t sound too unusual that you might cycle off 9.5. This doesn’t even take into account Friel’s post-workout hydration.
Consider yourself lucky. Lots of sweating is an indicator of a good internal air-conditioning system.
This is an excerpt from Friels “Hydrating in the Heat”
“To enhance absorption drink larger amounts less frequently rather than small amounts.”
Why? The main factor determining the rate of gastric emptying is the gastric volume - i.e. the more liquid in the stomach the faster the rate of emptying. (From Noakes “Lore of Running”.)