Wednesday, June 25, 2008

CPH/Miles = CPM

Oh the conversations cyclists will get into, both with each other and with "outsiders". CDV was telling me that somebody asked him in the coffee shop last Saturday how many Calories per Mile (CPM) that it took to ride a bike.

This of course got the analytical Algebraic side of my brain going (and if my kids read this, yes...you WILL use Algebra in your life whether you think you will or not!). Calories per Mile(CPM) huh? Let me think. Simple algebra. If you take Calories per Hour (CPH) and divide by Miles Driven (Miles) you should arrive with Calories per Mile (CPM). Easy enough.

CPH is the hard to determine factor. Some heart rate monitors will tell you based on your heart rate/weight how many calories you are burning per hour. I found a few charts online and I believe the following is "fairly" accurate so I'll use THIS for purpose of my calculations.

According to what my heart rate monitor (when I used to wear one) and what the chart says, somebody my size should burn a little over 1000 calories per hour when averaging 16-19 mph on a training ride, so we will keep it simple for calculation purposes and say 1000. So, burning 1000 calories for say 18 miles in one hour, we can now solve for Calories per Mile.

1000(CPH)/18(Miles) = 55.56 (CPM)

Figure yours out too so you to can amaze your friends should the question ever come up! Although it's an easy thing to figure out, somewhere out there I have a couple of happy math/algebra teachers. I expect this word problem to be in future text books. All royalty checks will be appreciated and expected.

7 comments:

jamesmommy05 said...

Hey! You know how great I am with technology! I practically lived in your office! Oh, I think I saw that biker guy that stayed at your house a while back, he was going up that BIG hill going out of Rapid City towards Hill City this morning on my way to work.

Iron "GeekGirl" Misty said...

Good boy. You even used your units throughout. A-, because in my classroom the problem was never fully solved until they answered the question in a complete sentence, e.g., "a person weighing ____ pounds. would burn ___ calories per minute."

Now for your final exam: write a general formula for how much a person burns per minute per pound of bodyweight? Hmmm.

bikingbrady said...

Damn you (former) teachers!

It would have to be "general" as I do believe Heart Rate would have to factor in as well. That being said, some reasonable average assumptions being made, it's doable.

barry said...

Perhaps you should turn it around and figure out the 'fuel efficiency' of biking - 3500 calories in a pound of fat, so what would the miles per pound be?

SD_pedalpower said...

I am at 38.46 cpm. Does that mean I am more efficient or just that I can ride longer before needing a cheeseburger?

Snakebite said...

OK, Einstein, put away the fricking calculator and just RIDE!!!

Tez said...

All the mathmatics made my heart race.....I wonder how many calories I burned just reading the comments!