# How much does donating blood affect the amount of oxygen in your blood stream at high altitude?

I am a regular blood donor and I am also a skydiver. We normally go to around 13,000 feet AGL (above ground level). Depending on how high above sea level the ground is, altitudes could be as high as 15,000 MSL (mean sea level) before a jumper is required to use supplemental oxygen.

At those altitudes hemoglobin is less effective at carrying oxygen, which is why hypoxia is a risk.

The following chart taken from this article about aviation and the body shows how oxygen levels decrease as altitude increases:

What I would like to know is if there is any research into the effect blood donation has on the blood stream's oxygen capacity? Is it possible to say that x days after a donation, due to reduced hemoglobin levels, operating at 15,000 MSL would be equivalent to operating at 15,000 + x MSL without donation?

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The American Red Cross (redcrossblood.org/donating-blood/donation-faqs) says it takes 4-6 weeks to restore hemoglobin levels. – kmm Feb 22 '13 at 17:40
Right but how much are hemoglobin levels reduced and what does that reduction do to the overall oxygen levels in the blood? If you lose x% of hemoglobin after donation then being at sea level would be equivalent to being at.... 5,000 feet MSL? Basically my question is: how much earlier will altitude affect the body after blood donation than without? – Charles Wesley Feb 22 '13 at 17:42

The oxygen-carrying capacity of the blood is:

amount of haemoglobin * % saturation

The average blood donation is approximately 10% of total blood volume. . Since the donation will have no effect on the % saturation, the oxygen-carrying capacity at each altitude will go down by 10%.

By inspection of the graph in the question, the % saturation goes down by 10% at 10,000 feet. So I conclude that donating 10% of blood volume is equivalent to ascending to 10,000 feet in terms of the effect upon the blood's oxygen-carring capacity.