We all know the feeling… someone we’re attracted to walks in the room, the minutes are counting down until we give a big speech, or we see the flashing lights of police sirens in our rearview mirror. There are countless reasons to be nervous in life, and we can’t always see them coming. Not only does this mess with our mind, but anxiety and nerves can also affect us in a physical way. Sweaty palms and an increased heart rate are common symptoms, but have you ever felt your stomach “drop” during a particularly bad case of nerves?
It can come on fast and strong, as though the bottom of your stomach has simply tumbled into your toes. It’s one of the clearest signs that our nerves are taking over, but many people still get worried when they experience that strange sensation. The answer is quite simple, in fact, and relates directly to our sympathetic nervous system, more specifically, to our body’s fight-or-flight response.
The Fight-or-Flight Response
Before you can understand the strange things that happen in your stomach when you’re nervous, it is important to understand the larger physiological response of the body during a time of anxiety. For hundreds of thousands of years, early humans were essentially just another species, and didn’t have the massive, global impact of today—when we alter ecosystems, dominate other life forms, and generally step outside the normal path of natural selection.
As a nascent species doing its best to survive in the world, human beings—like every other animal species—gradually developed a set of physiological tools and responses that would help aid survival in times of threat. When a wild animal chased you through the woods, or a rival group came to attack your tribe or steal your lands, the mind detects a threat and goes into action. This “fight-or-flight” response of the body consists of various changes that occur very rapidly that can boost one’s physical or mental focus/abilities for a short time. As the name implies, it helps the body either flee from danger or prepare for a fight.
For example, imagine that a member of a hunter-gatherer society was returning from a day of picking wild roots and berries deep in the forest. Upon hearing a loud rustling in the woods nearby, they would become immediately alert, sensing danger. Upon that recognition of a threat, the body would kick into action. The blood flow is quickly diverted away from less important organs, such as the stomach, and instead diverts to the body’s muscles, lungs and heart. Your body also begins to take in more oxygen, since the muscles require oxygen to function. These physical responses are paired to a hormonal release, primarily stress hormones like adrenaline and cortisol, which have a wide range of effects in the body—including the stomach!
Fight-or-Flight and the Stomach
Although you may only think of your stomach as being “in control” when you’re extremely hungry, the gut is often considered the body’s second brain, with over 100 million nerves running between the stomach and your brain, within a system referred to as the Enteric nervous system. With such constant avenues of communication between these two critical parts of your body, it shouldn’t be a surprise that the fight-or-flight response has a nearly immediate impact on your gut.
Blood is diverted away from the stomach when danger is detected, because digestive functions are not as important, in that moment, as blood flow to other parts of the body, i.e., the muscles and the heart. Cortisol is the hormone responsible for controlling or inhibiting certain non-essential bodily functions. On the other hand, adrenaline will loosen the stomach muscles, which can result in the sense that your stomach is roiling and grumbling. Some people also report that the sudden surge of adrenaline can lead to feelings of diarrhea, nausea or flatulence. Basically, activity in our stomach and small intestines shuts down during this fight-or-flight response, the nerves linked to our smooth stomach muscles become extra sensitive, and the activity in the large intestine increases.
We have many different words for the sensations of nervousness in our belly. Some people refer to it as “butterflies in our stomach”, while others compare it to your stomach “dropping”. Both of these descriptions make sense; the large intestine will loosen, allowing more movement and “fluttering” in your gut, while the sudden sensation of needing to go to the bathroom does have parallels with a “dropping” sensation. Similarly, our stomach can be “tied in knots”, a sad event can be “gut-wrenching”, or we simply might describe ourselves as having a “nervous stomach”.
All of these phrases and attempts to describe the physical effects are slightly different, largely because the fight-or-flight response does not appear in a single form for everyone. While some people might get the runs before an interview, other people may suffer from severe constipation. Anxiety may stimulate the appetite in some, and eliminate the appetite in others. Basically, we know that the brain and the gut are intimately tied by the nervous system, but the precise connections and effects one can have on the other is not fully understood.
A Final Word
For millennia, our fight-or-flight response was sharpened and honed in the wild, when our lives were truly in danger. While there are some situations that require a rapid, energetic response in the modern world, our society has evolved faster than our physiological responses. The surge of adrenaline and cortisol at the slightest bump in the night or moment of anxiety can be frustrating—as it can make us into a sweaty, jittery mess—but there isn’t any way to prevent those instinctual reactions. All we can do is educate ourselves on what our body does in certain contexts, so the next time your stomach “drops”, you’ll have a better idea of why!
- Medical News Today
- Medical Xpress
- Emerald Insight
- Phobias: The Psychology of Irrational Fear: The Psychology of Irrational Fear