Exercise for your Blood Brain Barrier

The blood brain barrier’s permeability is directly affected by physical exercise. Exercise reduces inflammation and makes the blood brain barrier less permeable. This physical effect helps prevent and minimize diseases such as Alzheimer’s disease and multiple sclerosis (Małkiewicz et al., 2019).

        The blood brain barrier (BBB) separates the central (CNS) and peripheral nervous systems (PNS). It controls the flow of nutrients, proteins, solutes, antibodies, cytokines, etc. between the blood and cerebrospinal fluid of the CNS (Małkiewicz et al., 2019). It is composed of multiple cell types, including astrocytes, microglia, and neurons. The most important structure for BBB function is tight junctions. Disturbing tight junctions, as well as gap and adherence junctions, results in reduced BBB ability (Małkiewicz et al., 2019). Inflammation is one of the most common ways to disturb tight junctions and increase BBB permeability (Abbott, 2000; Małkiewicz et al., 2019). When permeability increases, the BBB begins to “leak” allowing unwanted cytokines and immune cells to enter the CNS (Abbott, 2000; Małkiewicz et al., 2019). This leads to even more inflammation and increased permeability as inflammatory cells from the bloodstream enter the cerebrospinal fluid. This positive feedback can lead to cerebral edema and increased susceptibility to neuroinflammatory diseases such as Alzheimer’s disease, multiple sclerosis, epilepsy, Parkinson’s disease, and major depression (Abbott, 2000; Małkiewicz et al., 2019). 

        Physical exercise decreases inflammation and promotes proper tight junction function (Małkiewicz et al., 2019). Physical exercise reduces the release of inflammatory cytokines such as TNF-α, IL-6, and MCP-1. One study directly linked this reduction of cytokines to increased physical exercise in elderly women (Chupel et al., 2018). Prolonged inflammation in the CNS and BBB results in the loss of tight junctions and decreased BBB function. This can be combatted with physical exercise as it decreases BBB permeability, reinforces BBB antioxidants, and reduces oxidative stress (Małkiewicz et al., 2019). 

        These findings represent an ethical need to encourage and even prescribe physical exercise, especially in those susceptible to CNS pathology. By encouraging physical exercise, you will be following the ethical principle of beneficence because of the countless benefits that exercise has for most people. There is a small amount of people who have conditions that could be exacerbated by exercise, so not recommending them physical exercise would also represent non-malfeasance. Health professionals need to be mindful of their patient’s condition and physical ability before recommending increased exercise, but for most individuals the benefits of exercising reach far and wide and improve nearly every aspect of their lives, including the health of our blood brain barrier. 

References:

Abbott, N.J. Inflammatory Mediators and Modulation of Blood–Brain Barrier Permeability. Cell Mol Neurobiol 20, 131–147 (2000). https://doi.org/10.1023/A:1007074420772

Małkiewicz, M.A., Szarmach, A., Sabisz, A. et al. Blood-brain barrier permeability and physical exercise. J Neuroinflammation 16, 15 (2019). https://doi.org/10.1186/s12974-019-1403-x 

Matheus Uba Chupel, Luciele Guerra Minuzzi, Guilherme Furtado, Mário Leonardo Santos, Eef Hogervorst, Edith Filaire, and Ana Maria Teixeira. Exercise and taurine in inflammation, cognition, and peripheral markers of blood-brain barrier integrity in older women. Applied Physiology, Nutrition, and Metabolism. 43(7): 733-741. https://doi.org/10.1139/apnm-2017-0775