Walking's Optimal Speed Is About 1.3 M/s

Citing a 2004 Nature article, walking has a U-shaped oxygen consumption curve, with a minimum of about 165 millilitres of O2 per kilogram of body weight per kilometre at around 1.3 metres per second. Running, including jogging, shows a straight line decreasing from about 210 ml O2/kg/km at 2 m/s to around 200 at 6 m/s. For a given distance and a long time allowance, walking uses the least total oxygen. But if time is short, alternating between fast running and a brisk walk is optimal.

The figures reflect total oxygen consumption, not the extra above basal rate, which would favour a slower walk. Questions can be sent to lastword@newscientist.com.