Boiling Point of Water

• As altitude increases, the boiling point of water decreases. This happens because the atmospheric pressure on the water also decreases, thus decreasing the amount of energy required to boil the water. This change in boiling point can be a disadvantage to cooking at high altitudes, because the food which requires boiling water will need to be cooked longer at these lower temperatures.
  
  

Decrease in Oxygen

• As altitude increases, the available oxygen in the immediate atmosphere decreases. This can lead to respiratory difficulties and side effects such as nausea and headaches. For this reason, hikers who plan extended trips to high-altitude locations often bring an extra oxygen supply.
  
  

Stronger Ultraviolet Exposure

• Due to the thinness of the atmosphere at higher altitude, ultraviolet rays from the sun are stronger. They do not encounter as much atmospheric resistance as they do at sea level. The stronger ultraviolet presence at higher altitudes corresponds to a greater risk of sunburn and skin cancer if one is exposed for too long.
  
  

Altitude Training

• One advantage of high altitude is the ability for humans to train in such settings. The adaptation to this environmental extreme allows for greater athletic ability at sea level. Most importantly, exposure to the low oxygen levels of higher altitudes forces the body to adapt and become more efficient with managing a smaller amount of oxygen. Once these effects (such as an increase in red blood cells) have manifested in the body, the body will become more efficient with its oxygen use at sea level.