How does energy use by the body differ when I walk, jog or run for 1 kilometre?
Eric Kvaalen
Les Essarts-le-Roi, France
An in Nature gives a graph showing oxygen consumption as a function of speed for walking and running (鈥淓ndurance running and the evolution of Homo鈥�, 2004).
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For walking, the curve is U-shaped, with a minimum of about 165 millilitre O2 per kilogram body weight per kilometre at around 1.3 metres per second. Running (which includes jogging) is a straight line that decreases from around 210 ml O2/kg/km at 2 m/s to around 200 at 6 m/s.
This means that if you want to go a certain distance in a given, fairly long amount of time while consuming the lowest possible amount of oxygen, then you should walk.
However, when the allotted time is less than a certain value, corresponding to a slightly fast walk, then you should alternate between running as fast as you can and walking at that slightly fast walking speed.
My theory is that, because dogs don鈥檛 climb and have no aerial predators, they tend to not have much concept of 鈥榰p鈥�
Note, however, that this is talking about total oxygen consumption, not extra oxygen consumption over normal basal rate. To minimise extra oxygen consumption, the optimum is a slower walk than that for total consumption.
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