GLOSSARY

Oxygenated blood is blood that has taken up oxygen in the lungs, with its haemoglobin almost fully saturated with oxygen.

Characteristics

• Oxygen saturation (SaO₂): about 95–100 percent.
• Partial pressure of oxygen (PaO₂): about 80–100 mmHg.
• Oxygen content: about 20 millilitres of oxygen per 100 millilitres of blood, over 98 percent bound to haemoglobin.
• Colour: bright red.

Route

Pulmonary veins → left atrium → left ventricle → aorta → systemic arteries → tissue capillaries.

Clinical Application and Relevance to Sport

• Pulse oximeter: non-invasive measurement of oxygen saturation via the fingertip; values below 90 percent at sea level are concerning.
• Altitude: at high altitude, saturation may fall to 80–90 percent; the body adapts by increasing ventilation and, over weeks, red blood cells.
• Blood doping: artificially increasing red blood cells or using EPO to raise blood’s oxygen-carrying capacity is banned and increases the risk of clots and stroke.