Ditto the spinning class. On the bike, a small voice said, "Conserve. You have to get back to the car!" In spinning class, you can go full out. My instructor pushed me farther--I would never had stood and sprinted for an hour on my own. Plus, DH joined me and never left my side! After our first outdoor hill ride, DH said spinning did me good--he wasn't "totally" laying back :-) And now he doesn't get as long a rest at the top of hills (waiting on me) as he used to.
"Well-behaved women seldom make history." --Laurel Thatcher Ulrich
'09 Trek WSD 2.1 with a Brooks B-68 saddle
'11 Trek WSD Madone 5.2 with Brooks B-17