Hmmm. Never really thought about this, but I have the same resting heart rate as Karky, except I am horribly out of shape and quite overweight. Well, actually, that [50-55] is what my resting heart rate will usually be at any given time of the day when I'm sitting and haven't exerted myself recently. I've never taken it immediately upon waking.

When I'm biking at what I consider a moderate pace, (18 mph according to my bike, but that can't be right, it's too high), my heart rate will not exceed 105. Always wondered why this was the case. I had just assumed the sensors on my bike were crap. Now I'm quite curious to know more. Thanks!

Think I'll get me a Garmin 305 or something.

Here is an article (both web pages have the same article) that mentions the difference in heart changes for aerobic athletes versus anaerobic athletes. However, it refers to weight lifting, as opposed to HIIT / sprint cardio, as an example of anaerobic training. HIIT / sprint cardio does have aerobic intervals in between the anaerobic sprint intervals.

CardioValens.com : Matters of the Heart
Athlete's Heart - Just like other muscles, the heart responds to exercise with increased efficiency.

I've been waiting for months now for the new 705 to come out....so frustrating. First Garmin said November, then Nov. came and they said "in stores in December...but that came & went and now the stores say February, sheesh!!!

One thing I should mention....these calorie-counters are all very different. I have a lap-counter that I use in the pool when swimming. I enter the distance, stroke-style, my height, weight, etc, etc. I also wear an HR-monitor which counts calories as well: the discrepency in total calories burned in quite a bit. Same thing as compared to the Elliptical machine's counter vs. the HR-monitor. In the end, it's just projections with an accuracy of...say +/- 25%

The thing is though...you can use it to guage your consistency. As I continued to ride the same trail again and again, over time I was moving faster AND using less calories: I had lost weight, my body became more efficient and I was scared of mountain lions chasing me!

But guys....look at the bigger picture: a HUGE percentage of Americans don't exercise at all, and of the few that do, they probably don't touch the intensity we do. The idea is to get out and just make it happen, counting & tracking numbers is fun and somewhat useful, but in the end (for me).....it's just mind-candy.

ROCK ON!!! -Chillen

- Steve