Can I train my way out of altitude sickness?

No. Altitude sickness (AMS) does not discriminate based on fitness level. Olympic athletes can get sick just as easily as sedentary people; the only cure is acclimatization or descent.

How do I know if it's AMS or just fatigue?

A mild headache is common. If you have a severe headache, nausea, vomiting, or loss of coordination that doesn't improve with rest, assume it is AMS and alert your guide immediately.

Preventing Altitude Sickness on Mount Kilimanjaro

Prevent altitude sickness by choosing a route that takes at least 7 days to summit and strictly adhering to the 'pole pole' (slowly, slowly) pace. Consistent hydration, taking Diamox if cleared by your doctor, and descending immediately if you experience persistent symptoms are your best defenses.

Select a longer itinerary. Avoid 5 or 6-day routes. Choose a 7, 8, or 9-day route like Lemosho or Northern Circuit. The extra days provide necessary time for your body to acclimatize to the thinning oxygen levels.
Master the 'pole pole' pace. Your guides will say this constantly. Walk at a pace where you can comfortably hold a conversation. If you are gasping for air, you are moving too fast.
Hydrate aggressively. Drink 3 to 4 liters of water every single day. High altitude dehydrates you rapidly, which thickens your blood and makes it harder for your heart to pump oxygen to your brain.
Consult your doctor about Acetazolamide (Diamox). Many trekkers take 125mg of Diamox twice a day to help the body acclimatize faster. Start taking it 24 hours before you reach 3,000 meters and discuss side effects like tingling fingers with your physician before leaving home.
Eat despite loss of appetite. You will feel less hungry as you gain altitude. Force yourself to consume high-calorie meals. Your body burns significantly more fuel in the cold and at altitude.

Can I train my way out of altitude sickness?: No. Altitude sickness (AMS) does not discriminate based on fitness level. Olympic athletes can get sick just as easily as sedentary people; the only cure is acclimatization or descent.
How do I know if it's AMS or just fatigue?: A mild headache is common. If you have a severe headache, nausea, vomiting, or loss of coordination that doesn't improve with rest, assume it is AMS and alert your guide immediately.