What High Altitude Does to the Human Body

High altitude can cause lots of negative effects on the human body. Fortunately, there are some easy ways to make your next ski or hiking trip up to the mountains a lot safer.


Altitude exposure may result in changes in senses (e.g., vision, taste), mood, and personality. These effects are directly related to altitude and are common at over 3,048m. Some effects occur early and are temporary while others may persist after acclimatization or even for a period of time after a descent.

    • Vision is generally the sense most affected by altitude exposure. Dark adaptation is significantly reduced, affecting Soldiers as low as 2,438m and can potentially affect military operations at altitude. 
    • Mental effects most noticeable at very high and extreme altitudes include decreased perception, memory, judgment, and attention. 
    • Alterations in mood and personality traits are common during altitude exposures.

Dehydration is a very common condition in Soldiers at altitude. Causes include perspiration/sweating, vomiting, increased breathing, and diminished thirst sensation. Dehydration decreases physical performance, increases symptoms of altitude illness, and may increase the risk of developing cold injuries. 

 Poor nutrition can severely impact military operations and contribute to illness or injury, decreased performance and poor morale. At high elevations dulled taste sensations (making food undesirable), nausea, or lack of energy can decrease the motivation to prepare or eat meals. Poor eating habits may also lead to constipation, aggravation of hemorrhoids, and undesired weight loss.

 The easiest way to be safe with high altitude is to stay hydrated, eat less salt, and go to an Oxygen bar every other day if you are above 8,000ft. This will dramatically help blood flow throughout the body and cognitive function, to get rid of any altitude sickness that may come from lack of O2.