Altitude sickness (mountain sickness) is an ailment that occurs when the body is unable to adjust to high elevations (lowered oxygen levels). With the decrease in air experienced at high altitude the body does not receive enough oxygen to sustain the bodies requirements and hypoxia (lack of oxygen in the tissues) may result. It is recommended to slowly increase altitude each day if you are mountain climbing so the body is able to adjust to the atmospheric changes. Symptoms of altitude sickness range from severe headaches, labored breathing, nausea, numbness, tingling, difficult in breathing, cyanosis (blue lips), fatigue or fluid build up in the lungs or brain (edema/ hemorrhage). If acute mountain sickness does occur it is dangerous to continue moving higher, it is recommended to traverse a little way down the mountain and readjust appropriately before climbing again.
In regards to supplements/ medication to help reduce the incidence of altitude sickness please speak to your healthcare practitioner to best find the one suited to you. Due to the seriousness of this condition it is important to seek medical attention immediately if symptoms occur.