Our guides will use a pulse oximeter to measure the oxygen level in your blood and your pulse rate in the morning and evening. The oximeter is placed on a climber's fingertip. The oximeter uses two beams of light that shine into small blood vessels and capillaries in your finger. The sensor reflects the amount of oxygen in the blood.
Oxygen saturation is a measurement of how much oxygen your blood is carrying as a percentage of the maximum it could carry. Normal blood oxygen levels at sea level are 95-100%.
As altitude increases, oxygen saturations decrease. Proper acclimatization generally brings oxygen saturations higher, which is why these figures typically rise when oxygen saturations are tested after resting overnight. On Kilimanjaro, oxygen saturations percentages are regularly in the 80's. However, if oxygen saturation is ever less than 80%, we monitor that climber very closely.