I haven't been to Everest yet, most of my time is in the Alps, but I have been above 7k and for me, it's like walking around continually out of breath-- you have to do things really, really slowly.
I had a stupid incident on a 4K peak in Mexico -- I was doing a one-day climb and O was feeling great then like an idiot I started speed climbing to the summit. No problems until the decent, then I got a severe headache and could barely get down the mountain. I went from sea level to 4K in just a few hours and didn't pay attention to the altitude and without warning, I was almost on my knees. Even popular mountains like Mont Blanc (4810 meters) require a few days of acclimation, yet because Nevado de Colima is an "easy" mountain I didn't take the 4200 meters seriously. Almost a disasterous mistake.
My point is that above 4K, it pretty much sucks in terms of cardiovascular efficiency. Even Everest base camp is over 5k meters -- taller than anything in the Alps. Dehydration, snow blindness, feeling permanent exahausted.. it's a feat to hang out that high for very long. It isn't too hard to suffer above 4K for short stints (such as Mont Blanc for a day or two, but for weeks at a time, it takes a toll, even with acclimation.
I have nothing for respect for "beginners" that tip out on Everest or any Himalayan peak. The mental fortitude required is extraordinary.
Just a point of contention with the comment calling Everest a "beginner" mountain -- with a proper guide, even Eiger or the Matterhorn can be ascended by a beginner. A guide could drag a beginner up K2 (as insane as that might be,) the technical skills aren't the limiting factor on the big mountains, it's the endurance and mental toughness to survive in that environment. Perhaps K2 is a bit extreme, but technical skills are easily taught, what can't be taught quickly is how to read the mountain -- on Mont Blanc for example (and also Paradiso in Italy,) crevasses are often hidden under snowbridges, so you have to learn how to "read" the terrain. Interestingly, Mont Blanc is one of the deadliest mountains because people don't respect it -- they take a 3 day trip to Chamonix and think they're Ueli Steck and fall off the mountain or get hit by a Volkswagen sized rock crossing the Grand Couloir. Pretty much any mountain can be climbed by a beginner with the right guide, but that doesn't make them any less impressive.
By the way, I am not a "good" climber or an expert, I just love being up there and have immense respect for the people that make it look easy. It's anything but!
Don't know if that answered your question, but that's as good as I got!
I had a stupid incident on a 4K peak in Mexico -- I was doing a one-day climb and O was feeling great then like an idiot I started speed climbing to the summit. No problems until the decent, then I got a severe headache and could barely get down the mountain. I went from sea level to 4K in just a few hours and didn't pay attention to the altitude and without warning, I was almost on my knees. Even popular mountains like Mont Blanc (4810 meters) require a few days of acclimation, yet because Nevado de Colima is an "easy" mountain I didn't take the 4200 meters seriously. Almost a disasterous mistake.
My point is that above 4K, it pretty much sucks in terms of cardiovascular efficiency. Even Everest base camp is over 5k meters -- taller than anything in the Alps. Dehydration, snow blindness, feeling permanent exahausted.. it's a feat to hang out that high for very long. It isn't too hard to suffer above 4K for short stints (such as Mont Blanc for a day or two, but for weeks at a time, it takes a toll, even with acclimation.
I have nothing for respect for "beginners" that tip out on Everest or any Himalayan peak. The mental fortitude required is extraordinary.
Just a point of contention with the comment calling Everest a "beginner" mountain -- with a proper guide, even Eiger or the Matterhorn can be ascended by a beginner. A guide could drag a beginner up K2 (as insane as that might be,) the technical skills aren't the limiting factor on the big mountains, it's the endurance and mental toughness to survive in that environment. Perhaps K2 is a bit extreme, but technical skills are easily taught, what can't be taught quickly is how to read the mountain -- on Mont Blanc for example (and also Paradiso in Italy,) crevasses are often hidden under snowbridges, so you have to learn how to "read" the terrain. Interestingly, Mont Blanc is one of the deadliest mountains because people don't respect it -- they take a 3 day trip to Chamonix and think they're Ueli Steck and fall off the mountain or get hit by a Volkswagen sized rock crossing the Grand Couloir. Pretty much any mountain can be climbed by a beginner with the right guide, but that doesn't make them any less impressive.
By the way, I am not a "good" climber or an expert, I just love being up there and have immense respect for the people that make it look easy. It's anything but!
Don't know if that answered your question, but that's as good as I got!