The text addresses the myth that blood is blue in the body until it is exposed to air, explaining that blood is red inside and outside the body, but appears blue due to light scattering by tissue. It also notes that blood color varies with oxygen levels.

The belief that blood is blue inside the body is a common myth. Scientific evidence and reliable sources confirm that blood is always red. Veins appear blue due to light absorption and scattering effects, not because the blood inside them is blue. Professional and reliable web sources support these facts, debunking the myth effectively. Blood color changes slightly with oxygenation levels, appearing brighter when oxygen-rich and darker when deoxygenated, but it remains red. This has been confirmed by scientific consensus and reputable sources.