According to Harvard Health, feeling dizzy and fatigued after eating meals is fairly common in the elderly, occurring in approximately one-third of older men and women; however, it rarely occurs in younger people. This condition, called postprandial hypotension, can cause a lightheadedness, or dizzy feeling, which may lead to falling, or fainting. Although experiencing fatigue after meals by itself is not a concern, if you are experiencing fatigue after meals that is accompanied by lightheadedness or dizziness, it is imperative that you discuss it with your doctor.
The Merck Manual states that because the intestine requires a large amount of blood flow during digestion, after eating, the heart rate will increase and blood vessels will constrict in other parts of the body to compensate. In some elderly people, their bodies are not working properly, therefore, their heart rate will not increase, and their blood vessels will not constrict adequately, causing their blood pressure to decrease. This decrease in blood pressure causes a feeling of dizziness and fatigue.
If you are experiencing symptoms of dizziness or extreme fatigue after meals, your doctor may check your blood pressure before and after you eat your meals to determine if postprandial hypotension is the cause. Because people with high blood pressure and those with autonomic nervous system disorders such as Parkinson's and diabetes are more prone to this condition, your doctor may order tests to check for these conditions as well.
While there is no known cure for this condition, there are measures your doctor can prescribe if you are diagnosed with postprandial hypotension. Your doctor may recommend that you decrease the amount of anti-hypertension medications you are taking. Your doctor may request you to not take your medications immediately before or after meals, and may instruct you to lie down after eating. Consuming small, carbohydrate rich meals may help alleviate symptoms, and may be recommended. You may be instructed to decrease or eliminate caffeine as it causes blood vessels to constrict, increasing the symptoms of this condition.
Symptoms of dizziness and fatigue after meals are not to be taken lightly. According to "The American Journal of Clinical Nutrition," patients with postprandial hypotension are more likely to experience coronary events and death; therefore, you must seek medical help if you are experiencing symptoms of this condition. While postprandial hypotension does not cause death on its own, the drop in blood pressure can cause fainting that may result in falling, which could cause head trauma and possibly death.