The lymphatic system actively pumps tissue fluid back to the blood, preventing swelling and maintaining the body's overall fluid balance.
The supply of oxygen and nutrients to tissues is performed by the blood system, and involves a net leakage of fluid outward at the capillary level. One of the principal functions of the lymphatic system is to gather this fluid and return it to the blood system to maintain overall fluid balance. Fluid in the interstitial spaces is often at subatmospheric pressure, and the return points into the venous system are at pressures of approximately 20 cmH2O. This adverse pressure difference is overcome by the active pumping of collecting lymphatic vessels, which feature closely spaced one-way valves and contractile muscle cells in their walls. Passive vessel squeezing causes further pumping. The dynamics of lymphatic pumping have been investigated experimentally and mathematically, revealing complex behaviours indicating that the system performance is robust against minor perturbations in pressure and flow. More serious disruptions can lead to incurable swelling of tissues called lymphœdema.
The first episode of the English podcast “The Fascia Guide”. The Fascia Guide is a podcast about the living body, about new research and a new perspective on health, pain and what…
The episode was first published on the Swedish podcast Fasciaguiden on June 5, 2025. In this thought-provoking conversation, we meet Dr. Neil Theise — liver pathologist, fascia re…