More elevation navel gazing.
So on my most recent trip to Mt. Shasta with effort I got up to 11,125'.
I spent the night at Horse Camp (7900') and then we had porters lug our heavier equipment up to 50-50 at 9600'. With a night's sleep at Horse Camp I had no problem getting up to 9600'. Though a night's sleep at 50-50 didn't seem to make too much difference as it was still a struggle for me though at least this time I got past Helen "Lake" (10,400') and on to 11,125'.
Twice before I've climbed to Helen from Horse Camp. Sometimes it's easy sometimes it's not. I can't quite figure it out. I do wonder if I had spent another night at 50-50 if that would of made much difference but some while back on a group trip on the Hidden Valley route we spent two nights there and my climbing was still severely compromised despite being in excellent shape.
This is all starting to look like I might want to focus more on climbing on packed dirt (i.e. not scree and loose rock) since that's easier than snow, though when the snow is firm there's little difference between it and dirt. But snow softens through out the day and when the surface steepens and the day progresses you will find yourself kicking steps into the snow which takes effort. Even when you're using crampons you have to focus more on foot placement and that takes more effort than just hiking on a trail.
On dirt I've been past 13,000' and one time when we were up camping comfortably at 12,000' in the Mitre basin I know I could have summited Mt Whitney (whose newly remeasured altitude is 14,505') had I been anywhere near a good trail instead of trying not to slide down Crab Tree pass (12,600'). I've also been at Lower Boy Scout Lake and was able to climb past 13,000'. I've also been ill at LBSL and didn't recover even after a couple of days. Maddening.
In the Mitre Basin we slept at
Horseshoe Meadow Trailhead 10,200'
Some unidentified spot at 11,000' (what a slog that was because of the sand on the Pacific Crest Trail)
Then we went up through the Mitre Basin and slept at an unnamed lake just past Sky Blue Lake which was at 12,000.
Then I climbed up to nearly 13,000'.
At no time was I ill - I had a mild headache from driving up to Horseshoe Meadows, but it got better.
SO with a gradual ascent I am fine. Trouble is most climbs aren't nearly so accommodating in that respect. Counter intuitively starting high makes things easier because you're not expending nearly so much oxygen and energy, but that has its limits. It's tempting to test this out in Estes Park CO and at Hawaii's big island.
I had this idea that I'd drive up to Yosemite and climb Mt. Hoffman (10,850') twice to see if there was any difference between the first day and spending the night at 8200' and then doing it again. The other approach would be to drive up and do almost nothing and then try the climb the next day. (Maybe even try something higher like Mt Dana.)
The other funny thing is that I seem to have an internal altimeter. I hit a wall at 7200' and at 9600', but can adapt with time (usually an overnight), but if I'm tired I don't always adjust to 9600'. I'm also going to maybe not use Diamox, but instead use Aspirin to see if that makes a difference, because it thins your blood.
So I don't know how I'll get up Shasta. I know I can get up Whitney (need to get a permit for next year come Feb), but Shasta doesn't offer higher places to camp (besides the crowded and not pleasant Lake Helen). I need to find a way I can camp high without getting ill (by increasing my sleeping elevation no more than 1500') and then climb higher.