I’m sure that the difference, if there is one, is negligible. But this is the Dope. What’s the Dope?
It’s probably about the same amount of Calories, unless you’re falling instead of walking. But it puts a lot more wear and tear on your joints.
NY Times, 30 September 2015 reports that “In practical terms…you can burn nearly twice as many calories per minute climbing the stairs as strolling down the hall. Even descending the stairs requires more calories, per minute, than walking over flat ground.”
Walking down, you have to fight against falling, which requires more effort than walking on the flat. Many old people I know have no problem walking up, but struggle to walk down due to the stresses it places on the joints as they struggle to not fall.
You actually have to throw your leg down faster than gravity, and pull the other up against gravity. You move your legs more.
To avoid jolting the joints, you hold tension on the muscles.
It takes energy to create tension, even though academically power= force * speed, in a moving fluid like air or muscles, it takes power to make force even if speed is zero. (A helicopter hovering definitely needs to create power. While the molecules of a muscle wouldnt absolutetly have to use use power to stay still under tension, they don’t do that, they let go and go back on, perhaps in an effort to be efficient at walking on level ground. ) So anyway, the act of tensioning the legs to drop a step takes energy …
Meanwhile walking is highly efficient, as the energy used to stretch the leg muscle is returned when the leg retracts… the muscles act like springs… That would be why the muscles require power to stay still, they are made to efficient at doing the most frequent task… (movement on flat ground… )
On the other hand, per mile, shuffling, and probably even running, down a non-stepped incline takes fewer calories. I can shuffle down a hill, consciously trying to only use only slightly more effort than I do walking, and approach a running speed. Although I’m pretty sure it take more calories per hour than walking since you are moving your legs more per minute.
Isn’t fighting against falling a pretty decent definition of walking, anyways?
But you are using gravity to help you cover the distance, and to that extent not using your own energy reserves (calories). OTOH, you may actually use more calories because you are covering more distance, albeit with the help of gravity. An unknown factor is how much are you allowing gravity to move you. If you let gravity take over completely (i.e, falling) you won’t expend any extra calories.
Unless you are distracted, in which case you start flying. 