Postural Orthostatic Tachycardia Syndrome (POTS) affects the Autonomic Nervous System (ANS), the body’s “autopilot” that regulates automatic functions like heart rate, blood pressure, and digestion. While primarily known for causing an abnormal increase in heart rate upon standing, POTS frequently extends its impact beyond the cardiovascular system. Gastrointestinal (GI) issues are one of the most common non-cardiac complaints reported by patients. This GI distress, including severe nausea and vomiting, is a recognized part of the condition, stemming directly from the underlying autonomic dysfunction. The severity of these symptoms often fluctuates, sometimes limiting food and fluid intake.
The Direct Connection Between POTS and GI Symptoms
Most people diagnosed with POTS experience gastrointestinal symptoms, with reports indicating a prevalence of around 70%. Nausea is frequently the most common GI symptom reported, often accompanied by abdominal pain, bloating, and early satiety (a feeling of early fullness). Vomiting can occur as a severe extension of chronic nausea, sometimes triggered by orthostatic stress or eating. This pattern suggests a direct link between the body’s difficulty maintaining stable blood flow and the function of the digestive tract. Symptoms are often aggravated when a patient is upright or after consuming a meal.
Autonomic Control and Digestive Slowdown
The physiological cause behind the nausea and vomiting in POTS lies in the dysfunction of the ANS, which controls the entire digestive process. The stomach and intestines rely on the parasympathetic nervous system, the “rest and digest” branch, to regulate peristalsis, the coordinated muscle contractions that move food. In POTS, the imbalance in the ANS can disrupt this process, leading to abnormal gastrointestinal motility.
Blood Pooling and Reduced Flow
A primary mechanism contributing to GI symptoms is the mismanaged distribution of blood flow, known as pooling. When an individual with POTS stands up, the body fails to properly constrict blood vessels in the lower body, causing blood to pool in the legs and abdomen. This pooling results in reduced blood flow to the core, including the mesenteric arteries that supply the stomach and intestines. This temporary reduction in blood supply (ischemia) impairs their function and is a source of abdominal pain and nausea.
Gastroparesis
The autonomic dysfunction can also directly affect the enteric nervous system within the gut wall. This disruption can cause delayed gastric emptying, referred to as gastroparesis. Gastroparesis means the stomach takes an abnormally long time to empty its contents into the small intestine, and it is a major cause of chronic nausea, vomiting, and early satiety. While delayed emptying is a frequent finding, some patients experience the opposite, rapid gastric emptying, which can also trigger severe nausea and discomfort.
Managing Nausea and Vomiting Related to POTS
Managing POTS-related nausea and vomiting often requires a multi-pronged approach that focuses on stabilizing the autonomic system and supporting GI function. A fundamental step involves making dietary adjustments to reduce the digestive workload.
Eating smaller, more frequent meals throughout the day can prevent the stomach from becoming overly full, mitigating the symptoms of delayed emptying. The composition of the meal is also important, as foods that are low in fat and low in fiber are generally easier for the stomach to process and empty. For some individuals, eating while reclined or lying down can be beneficial, as this position reduces the gravitational stress on the ANS and may improve blood flow to the digestive tract during the meal.
Maintaining an increased intake of fluids and sodium is a standard recommendation for managing POTS and can indirectly help reduce GI symptoms. The goal is to increase overall blood volume, which helps counteract the blood pooling in the lower extremities and may improve blood flow to the mesenteric region. Oral rehydration salts or electrolyte solutions are often recommended.
For persistent or severe nausea and vomiting, a healthcare provider may prescribe medical interventions. Medications such as prokinetics can be used to help stimulate the movement of food through the digestive tract, addressing motility issues like gastroparesis. Additionally, antiemetics may be prescribed for symptom relief, allowing the patient to maintain adequate nutrition and fluid intake.