evidence: This type of hypoxemia typically occurs at higher altitudes. Oxygen in the air decreases with increasing altitude. Therefore, at higher altitudes, each breath you take provides you with lower oxygen levels than when you’re at sea level. [...] The organs and tissues of your body require oxygen in order to function properly. Damage can occur to vital organs like your heart and brain in the absence of enough oxygen. Hypoxemia can be fatal if it goes untreated.