As I mentioned earlier, it is highly recommended that you get to the area a few days early if you can. That way you can get near 10,000 feet elevation and give your body time to acclimate. You need to get at least a full night at an elevation at, or above the Whitney portal elevation (8360 ft.). Do not attempt this climb without at least that much altitude acclimation. We got there a few days early, spent a night at 10,000 feet at Cottonwood campground near Whitney, and then did about a 10 mile hike the following day. The day after that we got a full day of rest, still at 10,000 feet. We also drank a ton of water those few days. It is so important to hydrate as much as possible the days before your climb. I firmly believe the acclamation time, the hiking and the hydration the few days before our climb were the keys to a successful summit of Mount Whitney as well as the key to avoiding the dreaded altitude sickness. A word on altitude sickness: It can start with a little bit of dizziness or a headache and can progress to nausea and vomiting. If you get to that point, turn back immediately. It will get worse and the only thing you can do to make it go away is to descend. It can happen to anyone regardless of age, gender, or physical condition. If you press on it can start to affect your lungs and brain and can even cause death. The mountain is not going anywhere, so best to call off the trip and try again next year. The climb is not worth your life. So now, on to the climb.