How much fluid does one need in one hour of training/riding?

Last Friday, I tried to determine my fluid needs for training and the 7-day ride. Because I had not done the test correctly, I did the test again today. You can check Friday's post for details on how to determine your fluid needs. I weighed in at 153.5 lbs before the vigorous exercise, which was a spinning bike, and after 1 hour, my weight was 149.5.

What does this mean? 4 pounds of insensible losses and sweat. I will need 4 x 16 ounces = 64 ounces of fluid per hour of training. You shoulda seen that puddle of ... under the bike.

I carry two 24-ounce water bottles while I train. The fluid calculation as mentioned indicates that I need to consume the water/electrolyte mix in both bottles and then some basically every 12 to 15 miles. During my last few training rides, I've been drinking an equivalent to 1 bottle every rest stop. WOW 64 ounces! That seems much, but I'm sure on hot days, I won't have any trouble finishing my required intake.