Originally Posted by
OBoile
A significant change of speed should change your calories burned per mile. As you no doubt know, the force required to overcome air resistance is proportional to the square of the air speed. Going faster is less efficient.
Not as much as you'd think. Aero efficiency is king.
80% intensity for an hour:
23.5 miles w/ 153ft @ 23.5mph, 39.7kcal/mi
Riding home at significantly less intensity:
23.1 miles w/ 722ft @ 19.1mph, 36.8kcal/mi
So going back home a good bit slower, about 60kcal difference. But going uphill? I'm heavy. Climbing 6,000ft in 3 hours, I averaged over 80kcal/mi... at around 8mph.