Background: I generally try to follow the "spin up hills in an easy gear" strategy in both my commute and on group rides. It generally means I keep going to lower gears as I climb, and end up going pretty slow and at the end of the group (it's a pretty laid back group that either slows or stops at the top of big climbs to re-group)...(and the Monday night ride is mostly small rolling hills with one long 1-1.5 mile climb at the end) This has served me well, however, in that I am able to make it, and my legs don't hurt too much.

HOWEVER: Last week, I went on the group ride, and several factors were different:
-Very high heat and humidity, that I was not used to riding in.
-I had not biked or even exercised for about 2 weeks due to busy-ness
-I had not filled my water bottle all the way up because I usually don't drink it all anyway
-The few riders who are slower than me were not in attendance, so I was the slowest, trying to keep up with stronger riders on the climb.
SO...on the last climb, I had already run out of water, and once I got to the top, I felt weak and dizzy and had to lie down for a while (had a doctor on the ride, so I was in good hands). Felt fine once I got home and drank and ate.

In my last 2 (solo) rides since then, I (1) filled my bottle all the way with sports drink, AND (2) decided to experiment with climbing in a harder gear, higher cadence. What I discovered is that at the end of several of my normal climbs, I felt less winded than normal, and my theory is that i was previously climbing at too HIGH a cadence that, while saving my legs, was working my heart and lungs more than a slower cadence would.

Does this sound like accurate analysis? I'm sure there's a perfect balance somewhere, but I think I was relying too much on low gearing, and not enough on my leg muscles, which have quite a bit of muscle, and in general fair better climbs than my breathing does. (And of course, I need to not take weeks off of exercise such that I get out of cardio-vascular shape, right?)