If you really look at it, Kilimanjaro is a multi-day hike at altitude, although it remains challenging and shouldn't be underestimated. To get fit for Kilimanjaro on your Tanzania safari, the best preparation is to walk and hike and then do it all over again. You need to remember that hiking at high altitude is strenuous, so the more preparation you do before, the easier it will be on the mountain.
The best way to prepare is to build exercise into your daily routine with extended walks and hikes. It is a good idea to wear the same boots you will be hiking the mountain in and carry the backpack that you intend using. The more you exert yourself on these walks or hikes, the better you can increase your overall aerobic fitness. If this is combined with another aerobic exercise like running, yoga or swimming, even better. In addition, strength training is also recommended.
The big thing to remember is that you will be walking for numerous days, the fitter you are and the better prepared you are, the easier and more enjoyable it will be.
A three-month training program with a level of moderate fitness before embarking on a Kilimanjaro hike should suffice.
As with any fitness program, you have to eat right. Cut out fast foods and empty carbohydrates. You can only get out what you put in, with regards to food and when putting your body under physical stress for extended periods of time, it will need quality fuel to feed the muscles needed to get you to the summit. Drink plenty of water to keep hydrated and get into this habit because it's important to drink enough water when at altitude on the mountain.
Learn to know the limits of your body. A big part of hiking on the mountain is to recognize your own limitations and how far you are willing to push them if needed.
Join a gym or attend a fitness class. Find an activity that makes you work hard and get fitter, you are not looking at building muscle, you are looking for aerobic fitness. Do this at least 2 to 3 times per week. Remember it needs to be fun.
Walk was ever possible, take the stairs and not the lift. Try and fit a 10 to 20 min walk into every day.