Do short people tire more easily?

I think short people have an easier time in old age. My father is incredibly tall. His risk of falling and the damage done when he has had a fall are far greater because of this.

Im 4`11 cant say i do tire more.

Surely for walking it depends on leg length. I am fairly short but have long legs. I have a very short body. I can and do walk very long distances.

The only time that being small was much of a practical disadvantage for walking was on DoE when minimal kit still weighed more than the supposed 25% bodyweight guideline. I was carrying 3 stones rather than 2 in an ill-fitting rucksack.
When women's fit became avaliable to me some years later, it was a game changer.

The other time I struggled was a fitness issue after a rough, SPD pregnancy, and tough birth that aggravated it. When my pelvis was recovered enough to stop limping, I was still out of breath easily so took up C25k to improve my general fitness..

DH is tall and no slouch at walking pace, so I have a brisk walk keeping up with him.

I spend most of my time out and about wondering why most people bimble around so slowly as most are taller than me. I find slowly bimbling around town much more draining and heavy on my joints than a purposeful walk.

Interesting question! It sounds logical. Somebody has done some research on this and it sounds like your theory is right:

blog.smu.edu/research/2010/11/17/discovery-news-why-walking-is-harder-for-smaller-people/#:~:text=The%20reason%20smaller%20people%20use,same%20steps%20as%20taller%20people.

It makes sense. But do short people live longer? Anecdotal but I get the impression they do.

We have to take more steps, but we also have less bulk to lug around. But then we also have to eat a lot less than the average recommended to maintain a healthy weight, which kind of balances that out a bit. We need less energy, so we take in less energy, but need to do more movement and work to achieve the same physical things as others who are taller.

I think we do tire more easily, not just walking though. Being shorter than average in a society built for average means we're doing ever so slightly more work every time we have to reach for something, carry something large, push a shopping trolley etc etc and then of course take more steps whilst walking. I think maybe it's lots of small things that build up.