Stress: How It's Linked To Your Immune System And Nervous System

Over the last 30 years, much research has shown beyond a doubt that the nervous system and the immune system are intimately linked with each other, both physiologically and even the way they communicate with each other. This impacts our health and our well-being.

We have these small clusters of cells that are both nerve and immune cells, and they work together and cooperate. These cells let the nervous system know what's going on and enable the nervous system to influence the immune system.

So we've got these groups of cells, neurons, and immune cells, particularly in all our barrier skin areas and the internal gut. This information is transmitted via the fibres of the vagus nerve––the wanderer—which innervates all your organs, and it can tell the brain if there is an immune challenge somewhere in the body. There are other routes as well, neural routes that can influence the brain, but the vagus nerve is the main one.

You also have an indirect route where the body can communicate with the brain and tell us there's an immune challenge. This is via the circulatory system.

Suppose you have a local immune challenge, again like a virus, bacteria or an injury somewhere to the body. In that case, there is the release of local inflammatory mediators. Remember, in a previous post, we said that inflammation is a necessary step in healing; it's just that if it's overblown, it creates problems. Chemicals like cytokines are the ones that activate the vagus nerve. Still, they also can be taken up by the bloodstream and circulated to the brain.

These chemicals enter the brain through the blood-brain barrier and go very deep in the brain. Then, the brain can influence the immune system and communicate back to those immune cells what to do, again via two routes. One is the neuroendocrine route, and the other is via the autonomic nervous system.