Altitude Sickness

At the summit of Uhuru peak (5896 m, 19344 ft), the atmospheric pressure is less than 50% of the pressure at sea level. This means your lungs only get half as much oxygen with every breath as at sea level.

As you near the summit, every step requires effort, and ignoring the Kilimanjaro guide's matra of "pole pole" (pronounced "poh-lay poh-lay", and meaning "slowly slowly") will leave you gasping for breath.

Most Kilimanjaro climbers will experience some of the symptoms of altitude sickness, which include headache, loss of appetite, nausea, difficulty sleeping. Infrequently, more serious and life-threatening conditions such as pulmonary or cerebral edema (accumulation of fluid in the lungs or brain) may occur. Every year a few climbers on Kili die of altitude related problems.

A properly trained guide will recognize altitude problems and immediately evacuate a client with serious problems to lower altitudes. Some of the better tour operators also carry a device called a "pulse oximeter" which measures the heart rate and percentage oxygen saturation in the blood, in order to monitor clients for altitude problems.

You can also reduce the severity of altitude sickness by taking Diamox (acetazolamide) starting a day before and during your climb. Get a prescription from your doctor before you leave home. Diamox helps your body acclimatize, but it's also a diuretic and occasionally causes side effects such as tingling in the fingers and lips, and blurred vision.