A decline in blood-oxygen levels (hemoglobin) is observed when ascending higher elevations of more than 2100 meters (6.890ft) above sea level. The human body makes up for this by suppressing the ‘non-essential,’ secondary bodily functions—such as slowing down digestion. Increased production of red blood cells into the bloodstream leads to a faster pulse, and the body secretes stress hormones like adrenaline, cortisol, and growth hormone.