There is no other way to train for Himalayan altitude than to slowly acclimatize. Our Lamkhaga pass trek itinerary has been carefully planned to allow for gradual acclimatization (at Chitkul and Ranikanda). Altitude sickness can impact the fittest trekkers as easily as the less fit. If you’re on a trek, the main advice is to keep your fluid intake up to stay hydrated. Diamox (acetazolamide) is not recommended. Diamox simply tricks the body into breathing faster (by increasing the blood Ph slightly). It actually covers the symptoms. The best treatment for high altitude sickness is acclimatization or descent to a lower altitude.
How can I prepare myself for trekking at high altitudes?