Feeling dizzy after eating only rice~ <Post-meal hypotension>

A 57-year-old woman, Ms. A, experiences dizziness and lightheadedness whenever she eats something. The symptoms are especially severe after consuming carbohydrates like rice cakes, and one day she fell and injured her hand, requiring a cast for a while. Even when she visits the hospital, her blood pressure is only slightly low, and she is told that medication is not necessary. However, Ms. A is worried that she might fall again and suffer a fracture.

Person A is highly likely to be experiencing 'postprandial hypotension.' Postprandial hypotension is, quite literally, a condition where blood pressure drops excessively after eating. When a person eats, blood is directed toward the digestive organs to facilitate digestion. During this process, peripheral blood vessels need to appropriately regulate blood flow. However, as people age, the ability of peripheral blood vessels to control blood flow diminishes due to aging. This can result in an inability to prevent excessive blood flow to the digestive organs, leading to a decrease in blood flow to other parts of the body. When blood flow to the brain decreases, symptoms such as dizziness and lightheadedness may occur. The time when blood pressure drops typically occurs about 30 minutes to an hour after eating.

Post-meal hypotension is quite common, occurring in about one in three elderly individuals. It is also frequently observed in patients with Parkinson's disease or diabetes. By measuring blood pressure at home before meals and one hour after eating, if the systolic blood pressure (the highest blood pressure) drops by 20 mmHg or more compared to before eating, post-meal hypotension may be present. In cases of severe blood pressure reduction, angina or transient cerebral ischemic attacks may occur.

If you only experience slight dizziness and lightheadedness after a meal, drinking water before eating can alleviate the symptoms. Water expands the stomach, which in turn activates the sympathetic nervous system, inducing peripheral vasoconstriction. This prevents excessive blood flow from being directed toward the digestive organs.

Professor Son Jeong-tae's team from the Department of Nursing at Daegu Catholic University conducted a study with 25 elderly individuals aged 65 and above. On one day, participants drank 400ml of water (about two cups) before meals, and on another day, they ate without drinking water beforehand. Blood pressure was measured six times every 15 minutes over a total of 90 minutes after meals.

As a result, when eating without drinking water, systolic blood pressure dropped by an average of 16.7 mmHg compared to before eating. When drinking water, it decreased by an average of 5.4 mmHg. Generally, a blood pressure reduction of about 5.4 mmHg does not cause any significant problems. Diastolic blood pressure showed no significant change. Blood pressure changes are much more important in systolic than in diastolic.

Additionally, if you experience low blood pressure symptoms after meals, it is advisable not to take blood pressure medication before eating. Also, consuming too many carbohydrates can easily cause post-meal low blood pressure, so a low-carbohydrate diet is recommended. Eating quickly causes blood to accumulate in the intestines more easily, increasing the likelihood of post-meal low blood pressure, so it is better to eat slowly, starting with firm foods.