More lessons learned, regarding the sleep tent. Thanks to Dr. Peter Hackett for sharing a high altitude conversion chart.
1. Tiny changes to the air flow when above 16,000 feet make huge differences re: the FiO2 and relative altitude. I did not intend to go as high as I went, but…..glad I had an O2 analyzer to tell me where I really was.
2. I can sleep (at this point) totally comfortably to 16,404 feet.
3. I can sleep poorly to an altitude between 17,000 and 18,000 feet (O2 ~10.3%). Lots of waking up slightly [short of breath]. Tim Allen’s ghost visited my dreams many times (NB I killed him in a previous altitude-inspired dream).
3. Not so much sleeping at 19,000 feet, though I was impressed the machine could go so high so easily. Did not try that for long!
So, think I will hang around 16,000-16,500 feet for the next two weeks, then push to my highest planned sleeping altitude on the mountain (18,800) that last week before I leave for Africa.