What happens to atmospheric pressure as a person rises in altitude?

Atmospheric pressure decreases as a person rises in altitude.

Explanation:

The pressure is the ratio of the weight of the air to unit area. So, as the height increases, the pressure decreases. That is, the pressure is inversely proportional to the altitude. At such higher levels, the air molecules are very less than at lower levels. Humans can survive up to 20,000 feet that are 3.8 miles above sea level. This is due to the decrease in the oxygen rate called hypoxia, which means oxygen deprivation.  

Answerweathering;