I start the day before the hike and take a bit less Diamox. I also take two Extra Strength Excedrin before the hike. I up my daily dosage of CoQ10 and Ginkgo a couple of weeks before the hike. Have no idea if any of that works and scientific research says it shouldn't help, but no headache so far.
Water, water and water will help. Along with water, take some Cytomax, Gatorade or Vitalyte during your hike. Find some food you know you will eat. The sandwich that is so tasty at sea level often times is repulsive at 12,500 feet. So, a variety of foods, sncks. Gary (Bulldog34) turned me on to peanut M and M's. I like Snickers. My favorite bar is Clif bars. When Gary and I summited last time, there was a smorgasbord of food at the top of Whitney, including deserts, meats, etc. I checked it out and while I could have chosen anything, I chose an apple. It was delicious.
Not sure if you've done this, but read Doug Thompson's book. Check out videos of the main trail and there is even a map of available water stops somewhere on this site (Steve?)
Most important.... take your time and enjoy yourself. Bring a camera.
Okay....two more: Pee on the downhill side of the trail away from any water sources. And....use your wag bags.

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