Altitude sickness, also known as acute mountain sickness usually occurs when people try to ascend too quickly in altitudes beyond 2,500m (8,202ft.). It is very difficult to predict whether a trekker will get altitude sickness on the trek or not, but in the end everything depends on factors like prior exercises, previous hiking experience on high elevations, food & sleep, current hiking pace, physical fitness, medical conditions and mental health, and more. You can visit our Altitude Sickness: Cause, Prevention, and Treatment section to learn more about altitude sickness.