Note: This article only talks about shortness of breath after eating. You may want to read this article first to understand what is considered shortness of breath, and look at all the possible causes of shortness of breath in general.
Shortness of breath after eating: Decreased lung expansion
Decreased lung expansion could be the simple explanation of why you are short of breath after eating. This comes from the basic mechanism of how your lungs work when you breathe. As you can see in the picture, your lungs need space to expand when you take your breath. As you breathe in, your lungs push down on your diaphragm. Diaphragm is what separates your chest from your abdomen.
Your abdomen is filled with your stomach, intestines and other vital organs such as liver, pancreas and spleen. When you take a deep breath, you push your lung downwards. The diaphragm goes down and makes room for the expanding lungs. The diaphragm then pushes down on your abdominal organs. After you eat a large meal, your stomach can get distended. A distended stomach makes it hard for the diaphragm to push on it. As a result, your lungs do not get to expand fully. The lower part of your lungs may not get enough air. When it happens, you may have trouble breathing after eating a full meal.
It may seem like a very simple explanation of why someone may have shortness of breath after eating but I have personally seen patients who had serious problems with this. Shortness of breath after eating from decreased lung expansion can happen to anyone but people with obesity are very prone to it. In obese patients, the abdominal cavity is always distended because of excessive amount of adipose tissue stored in the abdominal cavity. They have decreased lung expansion all the time but they have more trouble breathing after eating.
In people with severe obesity, the decreased lung expansion not just causes shortness of breath after eating, but also leads to life threatening diseases. This condition is sometimes called pickwikian syndrome or obesity hypoventilation syndrome. When the lungs do not get space to expand for a long time, they continue to collapse more and more. At some point, the lungs become incapable of meeting the oxygen requirement of the body. The remaining normal part of the lung tries to squeeze more oxygen out of whatever air they get. In this process, the blood vessels of the lungs get damaged and lose their elasticity. That can put pressure on the heart and can lead to life threatening heart and lung damage. If you are overweight and have shortness of breath after eating a full meal, which could be a warning sigh that your lungs may not have enough space to expand properly with breathing. You need to see your doctor and get a formal lung capacity test where you breathe into a machine that measures how much air you are moving. If your lung capacity has reduced significantly, you need medical attention.
Trouble breathing after eating: patients with COPD
I have seen many people with COPD experience more shortness of breath after eating. There may be several different reasons why COPD patients have trouble breathing after eating but diaphragm pushing back against the lung can be an important consideration. . Many people with COPD have hyperextended lung, which means that they have lungs that are stretched out all the time because of loss of elasticity or recoil. As a result, they occupy more space in the chest cavity. The lung may already be pushing tightly against the diaphragm when the stomach is still empty. After a meal, the stomach takes up more space in the abdominal cavity and as a result, the diaphragm gets pushed back upwards. This can further impede the movement on already weak lungs in patients with COPD. As a result, they get more short of breath after eating.
The second reason why people with COPD get more shortness of breath after eating is slightly more complex. This particular mechanism causes trouble breathing after eating in patients with advanced COPD. These patients are very weak and frail. They may have shortness of breath at rest without oxygen. These people usually get short of breath with minimal activity at baseline. They are usually oxygen dependent. These people may get short of breath after eating because post-eating state represents a kind of stress on their bodies.
When you eat your meal, your body has to do some work to digest and metabolize that food. Your stomach has to physically churn that food down. Your digestive glands have to produce enzymes to digest the food. Your intestine has to squeeze the food downwards. The lining of your intestine has to absorb the nutrition and send them to the liver by blood. Your liver has to perform chemical processing of the nutrition based on the needs of your body. All these processes require expenditure of energy. Anything that requires more energy requires more oxygen consumption. More carbon dioxide is released from burning fuel when the energy expenditure goes up.
Patients with advanced COPD have very little reserve capacity of how much more oxygen their lungs can absorb and how much carbon dioxide they can get rid of. This increased need for oxygen after food consumption can be a significant stress on their lungs and they can have more shortness of breath after eating
Shortness of breath after eating: acid reflux
Acid reflux can be another reason why you have shortness of breath after eating. When you eat something, your stomach produces hydrochloric acid. This acid helps digest your food in the stomach. Sometimes, overproduction of acid causes it to come out of the stomach and climb up the food pipe. Occasional acid reflux can be normal but frequent acid reflux can cause problems.
Acid reflux has been known to cause shortness of breath after eating by irritating your air pipe. The acid can climb up and irritate your throat. It may make you cough or aspirate small food particles. That can lead to irritation and spasm of the air pipes that go inside your lungs. That can interfere with the smooth in and out movement of air from your lungs and you have shortness of breath after eating or even while eating. In patients who already have shortness of breath from asthma, acid reflux can make it worse. Some asthmatics may not notice the actual reflux of acid if it is mild. However, they may note that they have more trouble breathing after eating. That could be clue that they may have undiagnosed acid reflux. Acid reflux is also thought be a possible cause of worsening shortness of breath in patients with COPD. People with bad acid reflux tend to have more exacerbation of their COPD symptoms.
I hope this article about the symptom of shortness of breath after eating will helped answer some of the questions your questions about trouble breathing after eating. Please share this article with your friends and family and do not hesitate to post your questions and comments below. I cannot give you any specific medical advice but I can answer your general questions about what causes shortness of breath after eating.