How are the calories worked out?
By the American College of Sports Medicine’s walking equation, which gives the oxygen a walk costs each minute for each kilogram you weigh: 0.1 × your speed, plus 1.8 × your speed × the incline, plus 3.5 for what your body burns at rest, with speed in metres a minute and the incline as a fraction. Each litre of oxygen is about 5 calories, so the tool multiplies by your weight and the minutes you walk.
Why does incline make such a difference?
On the flat, most of the effort goes into moving forwards. Uphill, you also lift your whole weight with every step, and that cost grows with both the slope and your speed. At 3 mph (4.8 km/h), a 12% incline costs two and a half times as much as the flat.
Is 12-3-30 a good workout?
It’s a hard walk: about 8 METs, roughly what running at 5 mph (8 km/h) costs, without the impact. If you’re new to it, build up, starting with a lower incline or fewer minutes. And don’t hold the handrails: leaning on them takes weight off your legs and lowers what you burn.
How accurate is it?
It’s an estimate for steady walking between about 1.9 and 3.7 mph (50 to 100 metres a minute), the range the equation was made for; faster than that, a walk becomes a jog and the estimate gets less reliable. It includes what you would burn resting anyway. For walking on the flat, steps to calories works from your steps instead.
In StepUp
StepUp reads the active energy your iPhone and Apple Watch record on every walk, uphill or on the flat, rather than estimating it.
Questions
How many calories does 12-3-30 burn?
About 300 for someone weighing 70 kg (154 lb): roughly 43 calories for every 10 kg (22 lb) you weigh.
Does incline walking burn as much as running?
A steep one can. 3 mph at a 12% incline costs about 8.3 METs, the same as running at 5 mph in the Compendium of Physical Activities.
Should I hold the handrails?
Only to steady yourself. Leaning on them takes weight off your legs, and the calories here assume you carry all of it.