Absolutely. A lot of people will get symptoms of mountain sickness at around 4000 m. A go player I know attempted to climb Mount Kilimanjaro the summit of which is at 5895 m but had to quit around 4000 m because he felt too sick. To think that you'd spend at least a day in the death zone without supplemented oxygen feels surreal. The weather is typically awful. Wind speeds can be in the hurricane category with very low temperatures. 8848 m is not far from where commercial airliners fly.