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Why does lymph flow more slowly than blood?

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Diagram of the human lymphatic system highlighting lymphatic vessels and major lymphoid organs, including lymph nodes, adenoids, tonsils, thymus gland, spleen, appendix, bone marrow, and ducts. — lymphatic system The human lymphatic system, showing the lymphatic vessels and lymphoid organs.

Lymph flows more slowly than blood primarily because the pressure within the walls of lymphatic vessels is significantly lower than the pressure found in blood vessels.1

Unlike the circulatory system, which utilizes the heart as a central pump to drive blood at high pressure, the movement of lymph relies on different mechanisms. In mammals, lymph is transported through the system primarily by the massaging effect of surrounding muscle contractions, with a system of valves ensuring the fluid continues to move in one direction toward the bloodstream.21