Okay - I've got a weird question for you girls. I've been experiencing this for a while and am confused as to what is going on. Here is an example:

I was doing a brick the other day - 35mile ride, 3 mile run. It was my first workout after a rest week. I was drinking gatoraid throughout the ride, and stopped to eat an energy bar and take a bathroom break around mile 20. I had plenty of energy throughout the ride and run to the end. I averaged 16mph on the bike (excluding the warm-up) and kept a 10:30mi pace on the run. There was no wind and I was in the aero-bars through most of the ride. At about mile 28 it felt like my body completely shut down. I had to get out of my aerobars b/c I felt like my body was collapsing and my average speed went down to 11mph - and that felt like I was working harder than I had during the whole ride. The kicker was that my HR which had been staying between 160 - 165 (LT is 181) went down to the 140s at the same time (before I sat up). Then about 1 or 2min later I suddenly felt fine and went back down into the aerobars and back up to 16mph and didn't have a problem throughout the rest of the ride or run.

This has happened to me on multiple occasions, both riding and running, but this is the first time it has happened when I was watching my HR and had no energy problems throughout the ride. I always thought it was because my HR had stayed too high and needed time to recover, but it doesn't look like it. Do any of you gals have any ideas - I can use all the help I can get.

Thanks! (and I hope it makes sense)