You are attempting to climb an 8-thousander, so there is no question about the physical condition you should be in. All we can say is that you should be in the best shape of your life! For those who are seasoned climbers and are out on frequent adventure trips, you must be sure that you are comfortable waking for 5 to 9 hours with quite a hefty backpack. Start working out at least three months ahead of your trip with daily day-long hikes with a substantial weight on the back. Although the daily challenges will be different during the work-out phase, but your trip becomes smoother when you are both physically and mentally prepared.