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100 Calories consumed/mile?

  1. May 16, 2005 #1
    It is generally thought for every mile you walk or run, you burn 100 calories. Supose one were to walk uptown at a 15 degree climb for 2.5 miles and then walk back down 2.5 miles to the original start. It would seem this is harder than just burning 500 calories on a straight 5 mile walk.

    Newton's first law of motion seems to say, that nothing is achieve walking on level ground, but for the person it is exertion. I don't know what could be said about climbing hills and then coming back down to the original spot.

    Is there a practical Physics of sorts that has anything to say about this? Or is the only answer an attempt to discover the calories burned on the trip?
  2. jcsd
  3. May 18, 2005 #2


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    Instead of using theory, think in tems of what you know about hotwheels. You have 2 tracks:
    -a track that is 10 feet long, straight, and has an overall drop of 1 inch
    -a track that is 10 feet long, goes up and down, has an overall drop of 1 inch

    Which track would have the car going the fastest by the end? (which track is easier?)

    Maybe you've never done this before, but I have. I can tell you that the little car won't even make it to the end of the hilly track. Pretty much anything with hills in it requires a lot more energy. Going uphill then downhill would probably burn a lot more calories than just going straight.
    Last edited: May 18, 2005
  4. May 18, 2005 #3


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    Some experimental info : I took a look at last couple of exercies in heart rate monitor, slow pace (say 5 min/km) approx. 100 kcal/mile, fast pace (say 3 min/km) approx. 125 kcal/mile .... the "fast" pace is a bit difficult to estimate, would say it's between 120 - 160 kcal / mile. Typically I for one consume around 20-40% more energy in hilly terrain than on level if I keep the speed fixed (of course this only applies to "moderate" terrain, put enough slope and the exertion chart goes through the roof). You could approach it practically by way they do in HR monitors, then you'd just have to guess / test yourself what sort of HRs you'd exhibit as a function of slope angle etc.
  5. May 20, 2005 #4
    The body is not a simple machine therefore work/energy calculations are a function of each individuals body mechanics and metabolism. I remember my cross country coach telling us it takes more energy to go down hill due to the braking work done in our legs. This may or may not be true but it gave us a perspective that there is no free ride. If I were to race micheal phelps I would put out a lot more energy but come in far behind him.
    There must be some resource out there to get some data on calorie burning for humans walking, running etc. It would be interesting to see how elevation change effects calorie burning. For instance, would you burn more calories if you climbed a vertical ladder 100m then ran a horizontal mile or if you ran a mile up a steady slope with a 100 m vertical change? When Robert said practical physics i'll take that to mean simple or algebra based physics. We can use practical physics to determine the work done by the system (person) but determining the energy burned by the person would require modeling the human body with non-practical math.
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