Converging evidence from both human and animal models fully support the proposition that regular physical exercises aids the bodies endogenous system (Lymphatic System) to clear cellular waste and support your immune response. These finding have also recently been found to occur in the brain, termed the glymphatic system, to help your brains ability to function.
The Lymphatic System: Your Body’s Waste-Removal Highway
The Lymphatic System is a vast network consisting of ducts, nodes, and vessels which runs parallel with the circulatory system.
It’s responsible for several different things:
- Draining excess fluid from tissues back into the bloodstream
- Filtering out pathogens and cellular debris through lymph nodes
- Supporting immune surveillance by transporting white blood cells
- Absorbing fats and fat-soluble vitamins from the digestive system
The Lymphatic System may seem like it functions like the circulatory system by moving fluid through a series of ducts to circulate around the body. However, unlike the circulatory system there is now way for the lymph, whish is the fluid of the system, to pump on its own. The body figured out an ingenious way to circulate the lymph by way of contracting your muscles. By contracting muscles the lymph is able to fight gravity and travel up the ducts to be able to circulate.
Inactivity, therefore, will slow the rate of drainage allowing metabolic waste and inflammatory molecules to build up. This stagnant state will help contribute to swelling, slower recovery, fatigue, and even cognitive dullness.
Exercise, especially rhythmic movement like walking, resistance training, and deep diaphragmatic breathing, acts as a mechanical pump that propels lymph fluid through the body’s vessels (Hsu et al., 2021).
The Glymphatic System: The Brain’s Cleaning Mechanism
Until relatively recently, about a decade ago, scientists believed the brain lacked a lymphatic network. A breakthrough occurred at the University of Rochester discovering the Glymphatic System – a glia-dependent clearance pathway that mirrors the lymphatic system within the brain using cerebrospinal fluid (CSF) (Iliff et al., 2012).
Most of the benefit is derived during deep, slow-wave sleep, because interestingly the neuronal cells constrict slightly allowing for the CSF and interstitial fluid, fluid around the cells, to wash around removing built up waste. This waste can be a variety of molecules, some of which are now widely accepted as toxins like amyloid-β and tau (Xie et al., 2013) which are proteins linked to Alzheimer’s and generalized brain fog.
Sleep does not have to be the only time for your brain to clear out this metabolic waste build-up. Emerging research is coming to light on the effect of exercise and its ability to cleanse the CSF. Cardiorespiratory exercise as well as more subtle changes like postural corrections and daytime movement aids the glymphatic system to influence CSF dynamics helping maintain a baseline clearance throughout the day.
(I’ll dive more into why exercise is even more beneficial in a later section)
When Waste Isn’t Cleared: The Aβ–Tau Connection in Alzheimer’s Disease
In Alzheimer’s disease (AD), two key proteins – amyloid-β (Aβ) and tau – accumulate abnormally and disrupt synaptic communication. Traditional views, known as the Amyloid Cascade Hypothesis, propose that Aβ buildup triggers tau pathology, but new research has challenged this one-way model.
A comprehensive 2023 review highlights that soluble oligomeric forms of both Aβ and tau—not their insoluble plaques or tangles—are the most toxic to neurons. These oligomers impair long-term potentiation (LTP), which is the neural process underlying memory formation. Remarkably, both proteins appear to require the amyloid precursor protein (AβPP) to enter neurons and glia, essentially as a trojan horse, acting through shared pathways that damage synaptic function and memory.
This suggests that Aβ and tau operate in parallel through AβPP, not in series—creating a feedback loop that amplifies cognitive decline (Frontiers in Molecular Neuroscience, 2023).
Here’s where the glymphatic system becomes essential, inefficient clearance of these soluble proteins increases their interstitial fluid concentration, which accelerates uptake into neurons and worsens toxicity. Thus, a sluggish glymphatic system may indirectly intensify the molecular cascades of AD.
Movement: The Missing Link Between Body and Brain Detox
Physical activity is one of the most powerful ways to stimulate both lymphatic and glymphatic flow. Aerobic and resistance training improve vascular pulsatility and arterial compliance, which in turn enhance perivascular pumping of CSF through the brain. Animal and human studies show that regular exercise:
- Boosts meningeal lymphatic vessel growth and function (Da Mesquita et al., 2018),
- Increases glymphatic influx and clearance (He et al., 2021), and
- Reduces Aβ accumulation and cognitive decline through improved waste clearance (von Holstein-Rathlou et al., 2018).
Another fascinating aspect occurs after consistently performing aerobic exercise called lymphangiogenesis. This refers to the formation of lymphatic and glymphatic vessels from pre-existing ones driven by the stimulation of growth factors (as a side note its not fully understood at this time if glymphatic vessels “grow” or simply become enhanced/remodel). This means as people routinely exercise their baseline levels of this “waste management” system is increased helping to have a higher rate of cleansing throughout the day.
In short, when you move your body, you help your brain “breathe”.
References
- Da Mesquita, S., Louveau, A., & Kipnis, J. (2018). Meningeal lymphatics at the interface of brain and body immunity. Nature Reviews Immunology, 18(9), 571–582. https://doi.org/10.1038/s41577-018-0029-6
- Dongaonkar, R. M., Laine, G. A., Stewart, R. H., & Quick, C. M. (2021). Balance point characterization of lymph flow–pressure relationships in tissues. American Journal of Physiology–Heart and Circulatory Physiology, 320(5), H1881–H1890. https://doi.org/10.1152/ajpheart.00077.2021
- Gao, Y., Liu, K., & Zhu, J. (2023). Glymphatic system: An emerging therapeutic approach for neurological disorders. Frontiers in Molecular Neuroscience, 16, 1138769. https://doi.org/10.3389/fnmol.2023.1138769
- Hablitz, L. M., & Nedergaard, M. (2021). The glymphatic system: A novel component of fundamental neurobiology. The Journal of Neuroscience, 41(37), 7698–7711. https://doi.org/10.1523/JNEUROSCI.0591-21.2021
- He, Q., Li, L., & Nedergaard, M. (2021). Exercise enhances glymphatic clearance and reduces Aβ deposition in mice. Neurobiology of Disease, 148, 105219. https://doi.org/10.1016/j.nbd.2020.105219
- Iliff, J. J., et al. (2012). A paravascular pathway facilitates CSF flow through the brain parenchyma and the clearance of interstitial solutes, including amyloid β. Science Translational Medicine, 4(147), 147ra111. https://doi.org/10.1126/scitranslmed.3003748
- Xie, L., et al. (2013). Sleep drives metabolite clearance from the adult brain. Science, 342(6156), 373–377. https://doi.org/10.1126/science.1241224
- von Holstein-Rathlou, S., et al. (2018). Lymphatic drainage of the brain and the pathophysiology of neurological disease. Nature Reviews Neurology, 14(10), 563–577. https://doi.org/10.1038/s41582-018-0036-8