Why does anxiousness make us feel nauseated?

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Like, for example, if you eat something spoiled or otherwise gross you might feel nauseous because your body wants it out of your system. Same thing goes for if you eat way too much. I don’t see a reason why vomiting would help in the event of nausea, nor do I see how nervousness or anxiety would be able to manifest as the physical symptom of nausea.

In: Biology

Your stomach and brain are connected through the vagus nerve. When you feel anxious, your brain sends nerve signals to your stomach, making you feel nauseous.

When you are afraid, including anxious, your body shuts down systems that it won’t be needing to either run away from or fight the thing you are afraid of (like a predator.) So it basically halts/slows digestion and this gives you an upset stomach because food isn’t digesting like it should. This is especially harmful in today’s world because the system was developed to be very short term – you run away from that tiger and either you make it or you dont but you are only running awa/fighting for a short time. In today’s world as we are anxious for long periods of time it wrecks havoc on our digestive system.

There’s a few things going on but one of the most impacting is that stress, adrenaline, and the fight or flight response produce changes in blood flow inside of the body. One of these changes is a reduced amount of blood flow to the digestive system and some internal organs. More blood flows to the extremities and lungs to help you run away from the thing that is scaring you, which means less blood for digesting that last meal.

Digesting your food is a lot more complicated, an requires a lot more of your bodies attention than you probably realize. For instance did you know that you have more neurons inside your digestive system than a cat has in it’s brain? Did you know your digestive system had neurons that allow it to operate somewhat independently from the brain? Did you know that the overwhelming majority of serotonin ( a potent neurotransmitter) are created in the gut not in the brain?

Not only does it require a considerable amount of neurological power to synchronize all of the movements of the bowels and keep things working, but it also requires tons of blood and oxygen. All that food has to be absorbed by something, and it’s blood. The energy required to digest that food requires nutrients and oxygen supplied by the blood. This is one of the reasons you may feel lethargic after a large meal, or your heart may beat faster after a heavy meal.

Your inside guts are very complicated and squished together, so there arent as many nerves in there. Pretty much just the one, vagus nerve (can you distinguish your intestines over your stomach by feel alone?). When something is wrong, and your brain can’t figure out what, it assumes that theres something in that complicated squishy place, and send the signal to the one nerve that makes that nausea feeling.