What causes low blood pressure after a meal?

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Age 71yrs the last two days my blood pressure is very low 90/55 at one point 88/50 slight changes in vision seeing cross lines briefly.

1 Answer

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This is called 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 the process of digestion.

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, especially when standing.

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

In postprandial hypotension, it is thought that either the volume of blood in the gut is exaggerated or that the normal constricting of blood vessels in the lower extremities is diminished.

Eating high-carbohydrate meals appears to worsen postprandial hypotension. This observation has led some experts to 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.

To some extent, aging itself is accompanied by an increase in abdominal blood pooling that normally occurs after a meal. Most older people never develop symptoms from this increased blood pooling — but people who do have significant symptoms from postprandial hypotension tend to be elderly.