One important aspect of planning your hiking journey in the Himalayas is the (higher) altitude. As we go higher above the sea level the oxygen level drops (e.g. 50% at 5000m). It takes time for the human body and brain to adjust to this oxygen deprived environment. If we go up to quickly we can get altitude sickness (AMS) which if not taken care properly can be deadly.

Altitude is something that most of us do not bother about as most of us live in the plains or below 2500m altitude. As we go above 3000m however we need to give sufficient time to our body to "Acclimatize". General rule of thumb says do not increase more than 500m per day above 3000m. This means that if we plan for a 5000m pass crossing we should give at least 5 days (3000, 3500, 4000, 4500, 5000m) time if the hikers are not yet prior acclimatized.