Scientists experiment on themselves all the time, right?
I have a new heart rate monitor, the Suunto T4c, which has some nifty functions I'm still learning how to use. The main function is the "coach" - you tell it your activity level, some stats (resting HR, max HR, height, weight, etc) and it gives you bunches of fun information. The standard average and max heart rates (per workout) are there of course, and I can set zones. It also gives me calories, and something called "training effect" which I am still learning. It's on a scale of 1-5, and as far as I can tell, it uses average heart rate and exercise duration to assign a level. Based on that level and the goals you give it, it designs weekly workouts. I started actually paying attention to what it tells me yesterday.
Thursday 1/8/09: 40 minutes. Can't remember the goal TE, unfortunately
Friday 1/9/09: 30 minutes, TE 2.8
Saturday 1/10/09: 1:25, TE 2.8
Sunday 1/11/09: rest
Monday 1/12/09: 1:15, TE 2.5
Tuesday 1/13/09: 1:00, TE 3.1
Clearly it thinks I've been running too hard lately and need recovery, as 2.8 is a pretty low intensity. I'll be back later to discuss that more after I've read about it again. In the mean time, I plan to follow this the best I can for the next 4-6 weeks and see where it takes me. We shall see...