Anxiety can cause nausea and vomiting. This physical response stems from intricate connections between the brain and the digestive system. Understanding these reasons clarifies why emotional states manifest in distressing physical ways.
The Brain-Gut Axis
The brain and the gut are in constant, bidirectional communication through a complex network known as the brain-gut axis. This pathway integrates the central nervous system (CNS) with the enteric nervous system (ENS), often called the “second brain,” located in the digestive tract. The vagus nerve serves as the primary physical link, acting like a two-way information highway between the brain and internal organs, including the gut. This connection ensures that emotional states can directly influence digestive function, and conversely, gut conditions can impact brain activity and mood.
How Anxiety Affects Your Digestive System
Anxiety triggers physiological responses that impact the digestive system. The body’s “fight or flight” response, activated by the sympathetic nervous system, diverts blood flow away from non-essential functions like digestion and towards muscles and the brain, preparing for perceived threats. This redirection can slow down digestive processes, leading to discomfort.
Stress hormones, such as adrenaline and cortisol, are released during anxiety, influencing gut function. Adrenaline can alter gut motility, while elevated cortisol levels may affect the intestinal lining, potentially increasing its permeability. This hormonal surge can also increase stomach acid production.
Neurotransmitters also play a role in this complex interplay. Serotonin, largely produced in the gut, helps regulate bowel function. Anxiety can disrupt the balance of these neurotransmitters, affecting gut motility and sensations. Heightened anxiety can also overstimulate the vagus nerve, which directly influences gut sensations and muscle contractions, contributing to digestive upset.
The Body’s Vomiting Response to Anxiety
The physiological changes induced by anxiety can culminate in nausea and, in some cases, trigger the vomiting reflex. When the digestive system experiences altered motility, increased acid, or neurotransmitter imbalances due to anxiety, these signals are sent to the brain. The brain interprets these signals, leading to nausea.
If these signals are intense enough, they can activate the medullary vomiting center, located in the brainstem. This center receives inputs from areas including the chemoreceptor trigger zone (CTZ) and the vagus nerve. Activation of this center coordinates the muscle contractions and physiological changes necessary for vomiting, such as relaxation of sphincters and forceful abdominal contractions.
Understanding When to Seek Help
While anxiety-induced nausea and vomiting can be a common response to stress, persistent or severe symptoms warrant professional evaluation. It is advisable to seek medical attention if vomiting lasts more than 24 hours for children under two, or two days for adults. Other indicators for seeking help include significant weight loss, inability to keep food or fluids down, or if the symptoms interfere with daily life. If these digestive issues are accompanied by severe abdominal pain, chest pain, or signs of dehydration like dizziness and dark urine, prompt medical attention is important.