Tri-Thursday!!

Last night, as I made the realization that I would be more or less on my own this morning and could arrange my workout however I wanted, I decided to make it a tri-day.  Normally I go to spin class on Thursday mornings, but this morning I got up a bit early and went out for a 3.1 mile run before the kids went to school, then after I got them all out the door, I headed into the gym where I did an awesome spin class (with my favorite instructor-yay!), then after that I went straight into the pool where I swam 1/2 mile.  Here are my stats:

5k (3.1 miles) - 30:16 - 9:45 min./mile pace

Spinning, 1 hour (ave. heart rate during that hour = 170)

800m (1/2 mile) swim - 18 minutes

I'm really happy with how things went for me today.  Granted, I had a break between the running and the spinning, but still, I was glad that I felt strong doing my swim.  I don't know how many miles would be the equivalent of an hour of spinning, but I'm guessing it would be more than 20.  That guess is based on the fact that when I ride a regular upright bike at the gym for an hour, the distance readout is usually at least 20 miles, and I know I am working much harder and going faster when I'm in a spinning class.  Has anyone ever figured out how to gauge that?  I would be very interested to know.