What causes postprandial hypotension?

Digestion naturally increases blood flow to the stomach and intestines. The nervous system normally balances this by making the heart pump more effectively and narrowing some blood vessels. If that response is slow or limited, blood pressure can fall after a meal. The problem is more likely with ageing, dehydration, diabetes-related nerve damage, Parkinson’s disease, heart disease, or medicines that lower blood pressure. Large meals, meals rich in rapidly absorbed carbohydrates, alcohol, heat, and standing soon after eating may make symptoms more noticeable. Symptoms can include [Dizziness](/symptoms/dizziness/), weakness, blurred vision, nausea, or fainting.

Record when symptoms begin, what you ate, your posture, and any blood-pressure readings taken safely. Rise slowly, sit or lie down if light-headed, and avoid walking alone until steady. Regular fluids may help some people, but fluid or salt changes are not suitable for everyone, especially with heart or kidney disease. A clinician may review medicines, hydration, meal size, and related conditions. Do not stop prescribed treatment without advice. Arrange a [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) for repeated episodes.

Call emergency services for fainting with chest pain, severe breathlessness, a new irregular heartbeat, one-sided weakness, difficulty speaking, or prolonged confusion. Seek prompt medical assessment after a fall or head injury, or when episodes are becoming more frequent. Sit or lie down immediately during an episode and ask someone to stay with you if possible. Do not drive while dizzy or faint.

Ask whether a medicine, dehydration, diabetes, or an autonomic problem could be contributing; whether blood pressure should be checked before and after meals; and which meal or fluid changes are safe for you. Bring your symptom diary and a full list of prescribed and non-prescribed medicines.