Been hiking/scrambling peaks in the Sierra for many years. A few times over the last 4 years I got mild altitude sickness. But the last 2 trips up this summer it got to be a considerable handicap. I live at sea level and usually day hike over a 2-3 day weekend. After coming from sea level a day up on Tuolumne Peak, 10,845', the last 3 miles back found me with a nasty headache, mild nausea and doing a 3 percent grade was a challenge! Serious un-fun! Last weekend I even got the symptoms hiking 9,700' Fairview Dome but not as bad. Even the second day at 10,700' I was feeling it. Was going to do 12,590 Mt. Conness 3rd day and it might have been fine but..... decided on something lower.
Drink plenty of water! Stay fit and do big hikes locally, fresh as ever. Maybe it's age catching up. In any case anyone know any other remedies?