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There are several effects of high altitude on humans:

The percentage saturation of hemoglobin with oxygen determines the content of oxygen in our blood. After the body reaches around 7000 feet (2100 m) above sea level, the saturation of oxyhemoglobin begins to plummet.^[1]

Altitude acclimatization, the physiological adaptions to altitude, can have immediate and long term effects.

• Hyperventilation
• Fluid loss (due to a decreased thirst drive)
• Increase in heart rate (HR)
• Slightly lowered stroke volume

• Lower lactate production (because reduced glucose breakdown decreases the amount of lactate formed).
• Compensatory alkali loss in urine
• Decrease in plasma volume
• Increased Hematocrit (polycythemia)
• Increase in RBC mass
• Higher concentration of capillaries in striated muscle tissue
• Increase in myoglobin
• Increase in mitochondria
• Increase in aerobic enzyme concentration
• Increase in DPG
• Hypoxic pulmonary vasoconstriction
• Right ventricular hypertrophy

In the athletic arena, it is thought that acclimatization to high altitudes enhances performance compared to training at sea level. However, these assumptions have not been backed with any significant evidence. Contrary to these beliefs, studies have shown that athletes may not be able to train with as much intensity at high altitudes compared to sea level.

Yet, for those determined to adjust to high altitudes, without being at high altitudes, state-of-the-art altitude acclimatization devices exist. Chambers that reduce barometric pressure, hypobaric chambers with increased nitrogen concentration (which reduces oxygen), and tents that supply a limited amount of oxygen are used by athletes to acclimatize to high altitudes.

Finally, it is important to realize that to benefit from altitude acclimatization, one must stay in that altitude for a long period of time. Any benefits of altitude acclimatization are lost quickly by those who only dwell in high altitudes, or simulated circumstances, for a short amount of time.

• Altitude sickness
• Altitude tent
• Gamow bag

1. ^ Kenneth Baillie and Alistair Simpson. Altitude oxygen calculator. Apex (Altitude Physiology EXpeditions). Retrieved on 2006-08-10. - Altitude physiology calculator

• Physiology at MCG 4/4ch7/s4ch7_32
• Altitude sickness and high altitude acclimatisation