This was the most brutal hike I've ever been on. Man it was hard. I was 28 and in solid shape at that time, but everything after 13,500f was a struggle. My dog and I made it to the top, though most people we met who started the trail had to turn around. It's worth it though! On the way down a giant piece of rock went flying between me and my dog - we were lucky not to get hurt. Make sure you get on the trail before 7am.