I tried climbing Ojos del Salado (6,893 m / 22,615 ft) but only got to about 6.300 m. We spend around 10 days acclimatizing staring at ~3.500m and staying at various shelters at progressively higher altitudes. On 2 days I felt like shit (hangover like symptoms), rest of the days I was weak but it was manageable. Before the attack day I barely slept (I was tired, stressed and in a tent with people snoring). During attack it was really cold (like even with all the high altitude gear) and going up was super difficult. The worst part is that going down is also really hard so you have to calculate you strength for both ways of the trip but it really hard to judge how much more can you take. Half of the group resigned after first hour or two. The rest resigned when it became clear the weather is not improving and it will not be possible to get to the top.

Three days later I climbed Pico Vallecito (17831 ft / 5435 m). I used acclimatization from the failed attempt and just hiked to the top alone. It was quite hard, especially above 5000m I was moving slower than I expected. I wasn't very tired but I just didn't have energy to move at normal speed. Going down was easy so I made it down on time after all.