How Muscle Contractions Increase Lymphatic Flow
We often hear that exercise is “good for the lymphatic system.” But what does that actually mean — and has it been measured?
Research in humans has allowed scientists to actually visualize changes in lymphatic transport associated with exercise, providing evidence for something that has long been understood physiologically: movement can help propel lymph.
How Muscle Contractions Help Move Lymph
Many collecting lymphatic vessels contain intraluminal valves that help maintain directional lymph transport. When skeletal muscles repeatedly contract and relax, they change the pressure around lymphatic vessels. Think of this somewhat like repeatedly compressing a flexible tube with one-way valves. External pressure can help propel the fluid forward, while the valves help limit backward movement. This is often referred to as the skeletal-muscle pump. Exercise also increases blood flow and capillary filtration within active muscles. Other factors may also influence lymph transport, including changes in tissue pressure, arterial pulsations and respiration. Respiratory and circulatory influences appear particularly relevant to central lymph transport, although human evidence remains heterogeneous and does not establish a single dominant mechanism.
Research Studies
Research using modern imaging techniques has allowed scientists to observe how the human lymphatic system responds to exercise. Lymph Propulsion Velocity Increased ~47% After Cycling
In a study of healthy adults using near-infrared fluorescence imaging, lymph propulsion velocity increased from approximately 1.5 cm/sec → 2.2 cm/sec immediately after exercise. That’s an approximately 47% increase in measured lymph propulsion velocity. Interestingly, lymphatic contraction frequency did not increase immediately after exercise. This suggests that the increased movement of lymph may have been driven by contribution of external forces such as skeletal-muscle contractions and changes in tissue pressure.
A 2025 human ultrasound study provides additional evidence that exercise alters thoracic-duct dynamics: after 15 minutes of treadmill walking, the maximum thoracic-duct diameter increased by approximately 27%. The study did not directly measure lymph volume flow, however, so this finding should be interpreted as evidence of an exercise-associated change in lymphatic dynamics rather than a direct measurement of increased lymph flow.
A 2023 systematic review of human lymphatic transport research confirms that investigators can quantify characteristics such as lymph propulsion velocity, contraction frequency and pumping pressure and observe how these parameters respond to physiological interventions.
So What Is the “Best” Exercise for Lymphatic Flow in my personal opinion?
While the studies do not establish a “best” human exercise, physiologically, if the goal is to maximize the skeletal-muscle contribution to lymph transport in a healthy individual, it makes sense to prioritize activities that produce large-muscle contractions + repetition + sustained movement + increased respiration.
That makes activities such as running or jogging, cycling, rowing excellent choices.
Lower intensity is works as well, as it still provides continuous rhythmic lower-extremity muscle pumping — and importantly, walking itself has produced measurable thoracic duct changes in human research. Someone who cannot tolerate prolonged standing may perform seated ankle pumps or marching.Someone who cannot jump can perform repeated heel raises.
The important point isn’t that everyone needs to perform high-intensity exercise. It’s that movement matters. The goal is to create rhythmic muscle contraction and relaxation appropriate for that individual’s health and physical abilities.
For people with lymphedema, recent surgery, cardiovascular disease or other medical conditions, exercise recommendations may need to be individualized. More exercise is not automatically better, and exercise should be progressed according to medical and surgical considerations.
Bottom Line
The evidence supports a basic principle of lymphatic physiology: Movement can increase lymph transport.
Exercise combines several mechanisms that can assist lymph movement, including rhythmic skeletal-muscle contraction, changing tissue pressures, increased circulation and increased respiratory activity.
The takeaway: Your muscles don’t just move your body — their repeated contractions can also help move lymph.
References
Groenlund JH, Telinius N, Skov SN, Hjortdal V. A validation study of near-infrared fluorescence imaging of lymphatic vessels in humans. Lymphatic Research and Biology. 2017;15(3):227–234. doi:10.1089/lrb.2016.0061.
Breslin JW, Yang Y, Scallan JP, Sweat RS, Adderley SP, Murfee WL. Lymphatic Vessel Network Structure and Physiology.
Comprehensive Physiology. 2019;9(1):207–299. doi: 10.1002/cphy.c180015
Thorup L, Hjortdal A, Boedtkjer DB, Thomsen MB, Hjortdal V. The transport function of the human lymphatic system—A systematic review.
Physiological Reports. 2023;11:e15697. doi: 10.14814/phy2.15697
Scallan JP, Zawieja SD, Castorena-Gonzalez JA, Davis MJ. Lymphatic pumping: mechanics, mechanisms and malfunction. The Journal of Physiology. 2016;594:5749–5768. (The Physiological Society
Lymphatic Vessel Network Structure and Physiology. Review of lymphatic anatomy and physiology, including skeletal-muscle lymphatic transport and exercise. (PubMed Central (PMC)
The physiology of thoracic duct pressure and flow: A review of the literature. Systematic review examining respiratory, circulatory and intrinsic influences on thoracic duct lymphodynamics. (PubMed Central (PMC) (Visualizing lymphatic flow dynamics during complex physical therapy: A photoacoustic imaging study. Exploratory human imaging study examining lymphatic dynamics during exercise and compression.
