Is a stair machine comparable in effort to walking up real stairs?

Question

We're about to do a "stair climb" for charity in a few months and some of the team have been working out on the stair climber in the gym.

I'm not convinced this is the same amount of effort required compared to walking up real flights of stairs for two entirely unscientific reasons:

The stair machine is moving whereas the real steps require you to lift your body physically.

When I used to run, running on a treadmill felt approx. (for me) 20% easier than running on a road.

Does anyone know if my thoughts are in any way accurate and if so by how much are real stairs harder, or am I spouting complete...?

Answer 1

I don't have any hard data, but I suspect that, straight-up, stair machines will be slightly easier than actual stairs for one reason, air-resistance. A general rule of thumb I've heard for treadmill running is that you add a percent incline to model the air resistance of actually having to push forward. The second aspect, as you and Kourne alluded to, is that you're not actually having to move yourself, so the muscle mechanics will be different. Rather than pushing yourself up to the next step, you'll be doing a negative with one leg while lifting the other one. If you are allowed, or required, to hold onto the handles, this can also lead to bad habits where you hold your weight partially on them, negating some of the benefit.

The third aspect is that stairs in the real world usually have turns. This means that you will have slightly different stressors as you hit the landing and turn, and over long distances, there may be some degree of vertigo that you will not experience when using a stair machine. Personally, I find that going up isn't quite as bad as going down, but I suspect it will be present.