Medical Research — Idiopathic Orthostatic Hypotension & Gut Disorders

Many people who faint or get dizzy when standing also complain of stomach problems like nausea, bloating, and constipation. Idiopathic orthostatic hypotension (IOH) means blood pressure drops on standing and doctors do not find a clear cause. That drop can affect blood flow to the gut and change how the digestive system works.

Research and clinical observation are pointing to a real link between IOH and gastrointestinal (GI) disorders. When the autonomic nervous system is not regulating blood vessels properly, the gut can get less blood or have altered nerve signals. That can slow gastric emptying, reduce intestinal motility, and trigger symptoms such as early fullness, abdominal pain, or constipation.

Common signs to watch for include dizziness when standing, fainting, lightheadedness, plus nausea, bloating, acid reflux, constipation or intermittent diarrhea. If you have both kinds of symptoms, tell your doctor—treating one problem can help the other.

Diagnosing this link starts with simple tests. Doctors check blood pressure and heart rate while lying down and after standing. They may use a tilt-table test to confirm orthostatic drops. For gut symptoms, basic labs, breath tests for bacterial overgrowth, and imaging or referral to a gastroenterologist can help. Autonomic testing is useful when nerve dysfunction is suspected.

Treatment focuses on controlling the blood pressure drop and easing gut symptoms. Simple steps include increasing salt and fluids if your doctor approves, wearing compression stockings, and rising slowly from sitting or lying down. Medications like midodrine or fludrocortisone are options when lifestyle steps are not enough. For gut problems, diet changes, smaller meals, fiber, and prokinetic drugs can help under medical guidance.

Practical tips you can try today: sit at the edge of the bed and wait before standing, drink a glass of water before getting up, eat smaller meals more often, avoid heavy carb loads that can make blood pool in the gut, and keep a symptom diary to share with your clinician.

Doctors still need more large studies to map exactly how often IOH causes specific GI disorders and which treatments work best for both. New research is improving how we test for autonomic failure and gut motility, and this can change care over the next few years.

What doctors look for

Clinicians will review your medical history for conditions that affect nerves, blood vessels, or the heart. They check medications that can lower blood pressure and ask about meal timing and exercise. Tests may include ECG, blood tests for anemia or thyroid problems, and specialized autonomic testing if symptoms are severe or unexplained.

Everyday changes that help

Small habit shifts add up. Stand slowly, flex your legs before you stand, and avoid alcohol that can worsen drops. Try salty snacks or drinks when approved by your doctor to boost blood volume, and follow a diet to support gut motility. Share changes with your clinician.

If you suspect a link between dizziness and stomach issues, start by tracking symptoms and talking to your primary care doctor. You can explore our detailed post on this topic for more examples and practical steps.