It is very important for trekkers to attend acclimatization. Rushing to the higher elevation without acclimatization may result in acute mountain sickness (AMS) which could be fatal. Acclimatization helps to prepare our body to adjust and maintain a higher altitude situation. Our body takes some time to get used to the pressure and the thinning amount of oxygen as we ascend to the higher elevation. For the Everest Base Camp Trek, we have designed two acclimatization period; one at the height of 3962m/12995ft in Namche Bazaar and another after making an ascent of 4410m/14464ft