I live at sea level, and I am planning to go to Peru in June. While there, I hope to summit El Misti (5822m). I have climbed Mt. Elbert (4401m) after 2 nights at 3000m. However, I am a bit worried that El Misti might be too challenging. I plan to be at 3000m for around 5 days beforehand, since I will be hiking the Inka Trail.
Basically, I am looking for a training plan that I can do that will help me get in shape for this climb. Even simple guidance, such as on heart rate during training, or whether to focus on longer or shorter training hikes, would be helpful.
Some people get used to thin air quickly, some take longer and an unfortunate few can't acclimatize at all. A training plan has very little to do with that. It just takes time for your body to adjust.
Fortunately for you, the Inca trail is good preparation. If you can, try to add a night, or better two, at Lake Titicaca before traveling to Arequipa. There is no guarantee, but few people climbing Misti do more than that. Some do less and still get to the summit, some don't, and altitude sickness is the main reason for that. And most people are struggling with the altitude to some extent, including those that have been to Lake Titicaca.
Apart from the thin air, you obviously need to be in at least reasonable shape to hike up any big mountain, and if you are fitter, it will be more enjoyable. Personally, when I'm not in the mountains, I don't do all that much to stay fit. Roughly three times a week I do cardio. That can be running, at least an hour but very occasionally up to an hour and a half, or 45 minutes on the cross trainer, using an interval program. When I run, my heart rate is in the aerobic zone, on the cross trainer I push harder and it borders the anaerobic zone. In addition I do weight training, but you don't need that for Misti.
Lately I've come to conclusion that swimming longer lap sessions in the pool might actually simulate very mild hypoxia and get one used to limited breathing/air supply and breath discipline/control. Oddly, this might be thought of as "swimming to the summit."
Years ago I asked Hector Ponce de Leon what he thought the best physical training was for mountaineering (besides climbing itself), he said: "the Navy Seal program." hah! Go figure.
I've been told to avoid Tai Chi as the sole training program for higher altitude climbing.
I'm going to say that if you've trained prior and manage the Inca Trail easily whilst carrying a decent load everyday, that El Misti should not be too much harder. Yes, It will by a lot higher. That will be the main thing you'll have to contend with as weather tends to be pretty stable and clear during June, and the snow that you may hit towards the top will be well consolidated and usually perfect for crampons. I've lived in Arequipa for a year now and climbed El Misti a few times already and it just gets better and better!! In fact, during June I'll be using El Misti to train for Alpamayo and Huascaran and the following month in July. Those are In the Cordillera Blancas of Peru and 19,500ft and 22,200ft respectively. Maybe I'l see you up there!!! As far as training, def get in as good a shape as you can, with emphasis on good cardio and strong legs. Get some endurance in there so that you are comfortable carrying a decent pack ALL day long, ascending as well as descending. Sorry not the most formal plan, I'll have to leave the details to more knowledgeable people. Good Luck.