I started wearing one because I was so out of shape that a 100 meter trot at a slow pace would put me dangerously over my theoretical heart rate limit. I kept wearing one because it was a great, simple way to get back into shape—jog until I hit my limit; walk until I was 25% under my limit; rinse and repeat as long as I had time to do it.

Then one glorious day I jogged and jogged, and jogged and never hit my limit. Had to jog faster, and faster and faster just to get close.

It’s a great, simple training tool. It’s both reassuring (I’m not about to die) and motivating (I’m not pushing nearly hard enough).

But jogging is boring. It’s also hard on an aging frame. Variety is the spice of life. Throw in some cycling. Add a little inline skating. How about some kayaking when it’s not blowing too hard?

Now I’m more concerned with shedding pounds than getting into shape but my Fitbit activity tracker only understands how to convert STEPS into calorie expenditure numbers and my new, old frame friendly, alternative cardiovascular exercise don’t involve steps.

What to do? Upgrade my activity tracker and strap the heart rate monitor back on when I’m not running or walking for exercise. The problem is that almost all activity trackers (Fitbit, Fuelband, UP24, Pulse, Shine) understand steps and can sometimes differentiate between walking and running. They equate steps with calorie expenditure. If you aren't stepping you might as well be sleeping as far as they are concerned. That’s way better than nothing for 90% of us but I’m not one of them.

Cycling is the best mainstream example of this problem. I recently did an experiment where I rode the same 23K course two times in about one hour each time. My average heart rate was about 130 on each trip (OK I was dogging it). On the first run, my top-of-the line Garmin Vivofit was linked to my heart rate monitor. It recorded 629 steps I never took and credited me with 580 calories burned. On the second run (after a bowl of chili, three cupcakes and a nap) I left my HRM at home. That time VF recorded 879 nonexistent steps and awarded me with 107 calories which is barely more than I would have burned if I had been reading a book about cupcakes instead of blazing around Alameda like a comet on my orange bike.

Simple message—without the HRM, no steps = no calorie credit—HRM on board, make your heart hum and get the credit you deserve whether you are riding an orange bike or a red bull.

By the way, yesterday I did a similar experiment running a matched pair of 5K RUNS (think step-based) With HRM—5,015 Steps, 416 Calories. Without HRM—4,993 steps, 422 calories. Might as well have left the HRM hanging in the shower.

Hope this helps somebody.