Last week I did a 12.5 mile non-stop hike in Crystal Cove (Orange County area) with no real issues at all, although this hike was at sea level. I am not in great shape but i'm not out of shape either. So yesterday I finally got to summit White Mountain Peak (14,252 ft) and I was surprised at how incredibly tough it was. I am trying to find out why I found a 6.2 mile hike to the summit so difficult when I have done over twice the distance at sea level without stopping.
The first 2 miles from the trailhead to Barcroft station (12000') was great, the next 2 miles were ok..was getting a little out of breath and feeling a bit weak. I checked my altimeter and it was still 12700'. After that, the final 2.5 miles were absolute hell, from about 12800' - 14252', especially the last section from 13000' onwards I felt I could not even walk without getting out of breath, I would rest 2 minutes to get my heart rate back to normal and then take about 10 steps and my heart would be racing again. Through determination I made it but I felt others were doing just fine as they were just zipping past me.
My acclimatization process was camping overnight at Grandview campground (8600'). I'm guessing this was completely insufficient to acclimatize? I would like to hear about those that have had problems with altitude when summiting a 14er and how a better acclimatization schedule helped.