July 15, 2020

What causes the ‘Butterflies in the Stomach’ feeling?

If you’ve experienced uncertainty and anxiety, then you’ll opine that there is an unusual stomach sensation that accompany such moments.  

The feeling presents differently in different people. Some will have nausea while others will feel as if their stomachs are colonized by butterflies, literally.

Source: Shutterstock

During these uncomfortable moments, there are a lot of biological changes in your body. This article explores the scientific reasoning behind the feeling.

Changes in Your Nervous System

Your body systems have mechanisms to involuntary detect any change in your usual behaviour. In a bid to defend you, the body will change your heart rate, blood flow, and the distribution of crucial nutrients around the body.

These processes are regulated by the Autonomic Nervous System (ANS) and they are meant to prepare you for a reaction. The two possible reactions are:

Rest and Digest

This also called the parasympathetic system. It directs blood to the digestive system leading to a sleepy feeling. This explains why you develop a feeling of contentment and an unyielding urge to sleep after a heavy lunch.

Fight or Flight

This action is regulated by the sympathetic branch of the ANS. It increases your heart rate and diverts your blood supply to organs that require an intense supply of oxygen.

This is meant to prepare you to take off or face off the opponent adequately. For example, if you spot a leopard, it would be a waste if all the oxygen is used for digestion. Instead, it should be directed to your legs’ or arms’ muscles to strengthen you for a fight or flight.

Source: Medium

The sympathetic system also leads to an increase in adrenaline in your body. As a result, your blood supply and glucose levels increase which provides enough energy for the reaction.

Why “butterflies on the stomach”?

Since a significant amount of your blood is directed to the legs and arms, the stomach muscles slow down.

As a result, the blood vessels constrict and digestion slows down. Additionally, the external anal sphincter relaxes which increases the urge to visit the bathroom.

The combination of all these factors leads to unusual “butterflies feeling in your stomach“!

Balance Between Sympathetic and Parasympathetic Systems

Under normal circumstances, the two systems are balanced. However, in cases of tension, the sympathetic system overrides the parasympathetic system leading to the “butterflies feeling in the stomach”.

After a heavy meal, the parasympathetic system overrides the sympathetic system leading to contentment and a heightened urge to sleep.