The digestive system requires an increased flow of blood subsequent to a meal, in order to digest the food. This is ensured by dilating or expanding the blood vessels in the abdominal area, along with a slight increase in blood pressure (BP) there. The rise in BP in the abdominal area can cause a drop in BP in rest of the body. This can disrupt normal functioning of the body and lead to serious consequences.
To prevent this, the blood vessels in other parts of the body constrict or narrow down post a meal, so as to increase the blood pressure in them and ensure adequate blood flow. That is the reason, the heart beat and BP goes up slightly after a meal. This timely variation in blood pressure, as well as dilation and constriction of concerned blood vessels, is regulated by the autonomic nervous system.
However, in some people, the constriction of blood vessels in the rest of the body after a meal does not happen efficiently, thereby leading to a drop in BP, technically called Post Prandial Hypotension or PPH. BP is considered low when the systolic and diastolic pressures drop below 90-60 mm of Hg.
Signs, Symptoms and Complications
- Dizziness and light-headedness: This can occur anytime before 30-60 minutes after a meal. It can happen when the person suddenly stands up from a sitting position (called orthostatic hypotension) or can happen otherwise too.
- Fainting, medically called syncope.
- Some people may experience nausea or vomiting and wrongly attribute this to food poisoning.
- Some people may experience angina or chest pain.
- Blurred vision
- Feeling confused or disoriented
- Minor strokes called as transient ischemic attacks
- Complications from PPH include the body going in to a state of shock, and/or organ failure(s). Also, falling down due to dizziness increases the risk of fractures and injuries.
Causes and Risk Factors
There are multiple reasons attributed to PPH:
- Genetics: For whatever reason, some people are more vulnerable to PPH than others.
- Blood sugar: If the person has consumed a high-carbohydrate meal, the sudden spike in blood sugar and hence insulin is known to interfere with the working of the autonomic nervous system. For the same reason, diabetics are at high risk of PPH than non-diabetics.
- High BP: People who have constant high BP are at high risk for PPH. This is because the constant high BP makes the arteries stiffer and as a result, the dilation and constriction of blood vessels in different parts of the body does not happen efficiently. The BP sensors in the autonomic nervous system lose their sensitivity, triggering PPH eventually.
Other risk factors include:
- Age: Age is the biggest risk factor, as PPH affects people above 65 years than younger people. Age related changes interfere with the body’s ability to respond to changes in BP.
- Diabetes: As explained above, diabetes and random variations in blood sugar can trigger PPH
- Parkinson’s disease: An auto-immune disease, Parkinson’s affects smooth functioning of the autonomic nervous system, one of the consequences of which can be PPH
- Medication for high BP: Patients who suffer from high BP are given drugs to reduce or keep the BP in check. Sometimes, these can be very effective and cause a drop in BP.
- Trauma: A stroke, accident, or other trauma can damage key nerves or BP sensors eventually triggering PPH.
- Dietary triggers: Certain foods which cause migraine headaches can also trigger dizziness after a meal. This may or may not be a case of PPH. This includes alcohol, nuts, dairy products, chocolate, food containing monosodium glutamate and pickled foods.
- Certain medication: Some drugs can also trigger low BP, in which case, the low BP may or may not be a case of PPH. This includes certain diuretics, alpha blockers, beta blockers, drugs used to treat Parkinson’s disease, certain antidepressants and drugs used to treat erectile dysfunction.
The doctor will do one or all of the following:
- Track your BP both before and after meals over a period of time to note the extent of drops.
- A blood test to check for anaemia or low blood sugar
- An ECG to look for heart rhythm problems or arrhythmia
- An echocardiogram to evaluate the heart’s structure and function
As of date, there is no permanent or 100% cure for PPH. Even drugs prescribed for the same are only meant to minimize the condition. For example, the doctor may recommend nonsteroidal anti-inflammatory drugs (NSAIDs) before a meal. These drugs retain salt and help keep the BP up.
However, there are various preventive measures that help minimize the condition.
- Whole-grains in your diet: Whole grains and plenty of fruits and vegetables are rich in fibre and slow down digestion, thereby preventing a spike in blood sugar after a meal which typically happens if one consumes refined foods.
- Smaller meals: Similarly, it’s good to have smaller and more frequent meals which help prevent spikes in blood sugar.
- Water before meals: Drinking 1 to 1 ½ glass of water 15 minutes before a meal can prevent a drop in BP
- Caffeine before meals: Drinking coffee 30 minutes to an hour before meals can also prevent a drop in BP. However, please note, different people react differently to caffeine, and in some people, caffeine itself can cause dizziness.
- Less activity after a meal: In the hour following a meal, it’s good to sit or lie down to prevent a dizzy spell. If you must rise from the sitting position, do so slowly and not abruptly.
- Being active otherwise: Other than the post-meal hour, it’s good to be very active in general as this helps manage your heart health, and keeps your autonomic nervous system in good shape.
- Avoid alcohol and food that is rich in added salt, both before or during meals.