Postprandial Hypotension: Blood Pressure Drops After Eating

Postprandial hypotension occurs when blood pressure significantly drops after eating. This temporary change can cause symptoms such as dizziness, nausea, lightheadedness, and even fainting and related falling injuries. To fend off these symptoms, it's important to eat more often throughout the day and consume more low-carb foods if possible.

Postprandial hypotension is more common in older people and those with underlying health conditions, including diabetes and Parkinson's disease. A healthcare provider can diagnose it based on your symptoms and blood pressure readings taken before and after you eat.

This article explains the symptoms, causes, and treatment of postprandial hypotension. It also presents lifestyle changes, such as exercise and eating smaller meals, that can help with the condition.

At-Risk for Postprandial Hypotension

Postprandial hypotension is most commonly seen in older adults. Up to one in three older adults will have some degree of postprandial hypotension. This is defined as a drop in the systolic blood pressure of up to 20 mmHg within two hours after a meal.

For most of these individuals, the condition is mild and does not trigger symptoms. In some people, however, postprandial hypotension can become quite serious.

Postprandial hypotension is one particular form of orthostatic hypotension (a drop in blood pressure while standing up). It is more likely to affect people with high blood pressure, or with certain conditions that impair the autonomic nervous system, such as Parkinson's disease and type 2 diabetes.

Symptoms of Postprandial Hypotension

People who have postprandial hypotension often experience lightheadedness, dizziness, weakness, or even syncope (loss of consciousness) when they stand up within one or two hours after eating a meal.

Symptoms tend to be more severe after eating a large meal or one that is heavy in carbohydrates. Consuming alcohol before or during a meal can be another contributor. These symptoms usually resolve within two hours or so after finishing a meal.

Causes of Postprandial Hypotension

While the cause of postprandial hypotension is not completely understood, it is thought to be related to the pooling of blood in the abdominal organs during digestion. There's evidence that links the condition to the following factors:

• Meal composition and the type of foods and nutrients eaten
• Gastric emptying, or how fast food moves from the stomach to the intestines
• How well (and where) nutrients are absorbed from the digestive tract

As a result of this pooling, the amount of blood available to the general circulation decreases, causing a drop in blood pressure. Standing up increases this effect.

Some blood accumulation in the abdominal organs after a meal is normal since digesting food requires increased blood flow. To compensate, the blood vessels in the legs naturally constrict as a reflex.

High-Carb Foods

Eating high-carbohydrate meals appears to worsen postprandial hypotension, but proteins and fats also lower blood pressure in older people after a meal.

Some experts theorize that in people with postprandial hypotension, insulin or other blood chemicals that are released in response to a high-carb meal may cause excessive dilation of the abdominal blood vessels.

Aging

To some extent, aging is accompanied by an increase in the abdominal blood pooling that normally occurs after a meal. It rarely occurs in younger people, and most older people never develop symptoms from this increased blood pooling.

Those who experience significant symptoms from postprandial hypotension tend to be older.

Blood Pressure Medication

If you take medication for high blood pressure and experience postprandial hypotension, talk to your healthcare provider about adjusting your prescription. Studies have shown that people on antihypertensive medications may be more likely to have falls and suffer from drops in blood sugar after eating. The stronger the medication, the greater the risk.

Treatment

While there is no specific treatment to eliminate postprandial hypotension, most people can learn to control the symptoms. Treatment involves four elements:

• Eat smaller, more frequent meals: Eating large meals tends to exaggerate abdominal blood pooling. Smaller meals mean less blood pooling.
• Drink water before eating: Drinking 12 to 18 ounces of water 15 minutes before eating can offset some of the postprandial response.
• Avoid high-carbohydrate foods: Skip bread, pasta, and potatoes. Even fruits that are good for you like apples, mangoes, pears, and raisins are high in carbs.
• Stay seated: Or, if symptoms are severe, lie down for an hour or two after eating. Abdominal blood pooling tends to dissipate within this time period after a meal.

Some experts also recommend avoiding alcohol, because it relaxes blood vessels and tends to prevent the constriction of blood vessels in the legs that would normally compensate for abdominal blood pooling.

If these measures are insufficient, other therapies commonly used to treat orthostatic hypotension may be helpful. These include:

• NSAIDs: Taking nonsteroidal anti-inflammatory drugs (NSAIDs) prior to a meal can cause salt to be retained, thereby increasing blood volume.
• Caffeine: This can cause blood vessels to constrict and may reduce symptoms.
• Guar gum: This thickening agent may slow the emptying of the stomach after a meal, helping to relieve symptoms.
• Exercise: Getting plenty of exercise between meals—such as walking—can improve vascular tone and diminish symptoms of postprandial hypotension.

People living with diastolic heart failure who are being treated with diuretics may be more at risk of postprandial hypotension. They may find that withdrawing diuretic foods (that get rid of excess water) from the diet, such as certain fruits and herbs, will improve their symptoms.

If symptoms are severe and cannot be controlled by other measures, subcutaneous injections of octreotide (a drug that behaves like the pancreatic hormone somatostatin) before a meal may help reduce the amount of blood flowing to the intestine. However, this treatment is quite expensive and can cause significant side effects.

Summary

Postprandial hypotension refers to a dramatic blood pressure drop that occurs when someone stands up after a meal. It's more common in older people, and those with certain diseases, including diabetes.

The blood pressure drop can lead to symptoms of dizziness, lightheadedness, weakness, and even a loss of consciousness. Postprandial hypotension is still poorly understood, but some evidence suggests it's related to the pooling of blood that occurs in abdominal organs during digestion.

Because the blood pools in one place instead of being circulated everywhere in the body, it sets off a drop in blood pressure. Lifestyle changes and, in some cases, medication, can help keep postprandial hypotension under control.