During the COVID-19 pandemic, some patients would be tested with an oximeter only for it to read above 99 percent. Yet, during a medical checkup, they would be found to have a “lack of oxygen in the heart,” or hypoxia. Why is this?
It has to do with the type of hypoxia one has. According to Dr. Chungpin Liu, a cardiologist and the director of Yupin Clinic in Taiwan, there are three types of hypoxia.
The first is caused by not inhaling enough oxygen. For instance, drowning, choking on food, having a COVID-19 infection, or having other lung diseases, can cause low blood oxygen.
Dr. Liu pointed out that this condition is a systemic hypoxia. Such patients can detect a lowered oxygen concentration in their blood when testing with an oximeter.
The second type is due to poor blood supply. The reason may be that the patients’ blood vessels are naturally prone to spasm, resulting in poor blood flow. Or, due to poor lifestyle habits, fat and bad cholesterol accumulate on blood vessel walls, which become thicker and thicker, causing the blood vessels to become narrower and harder. This will eventually result in atherosclerosis, which prevents blood from flowing smoothly to the tissues.
If the blood supply to the tissues and organs is poor, local hypoxia will occur. For example, when the heart gets less oxygen, it will cause cardiac hypoxia.
Dr. Liu pointed out that most types of hypoxia, including heart hypoxia, are local, which cannot be detected by an oximeter.
Other cases of local hypoxia due to poor blood supply include limb necrosis caused by an accident, in which a limb is crushed by a heavy object, or when people tie a rubber band around their fingers, which turn black due to reduced blood flow.
The third is the insufficient ability of red blood cells to carry oxygen.
The hemoglobin in the red blood cells is responsible for carrying oxygen, and the red blood cells are responsible for transporting oxygen throughout the entire body. If there is a lack of hemoglobin, the ability of the red blood cells to carry oxygen will be reduced. Similarly, without sufficient red blood cells, sufficient oxygen cannot be carried. Therefore, patients with poor blood cell function and severe anemia are prone to local hypoxia.
Neglecting 3 Symptoms of Hypoxia Can Cause Heart Failure and Myocardial Infarction
Heart hypoxia can also be called hypoxic lesions and ischemic heart disease, as its most important factor is the blockage of the coronary arteries in the heart. The occurrence of hypoxia can be chronic or acute.
- Acute cardiac hypoxia
When acute platelet agglutination (platelets clumping together) occurs in the blood vessels, resulting in thrombotic (vein or artery) blockage, it will cause acute hypoxia. Myocardial infarction belongs to this category, as its onset is rapid and violent, and patients often quickly collapse. Myocardial infarction may occur because of the fragility of the blood vessel walls. Or, a patient becomes very tired and hasn’t drunk enough water, and suddenly a blood clot grows, and myocardial infarction takes place.
- Chronic cardiac hypoxia
Compared with acute cardiac hypoxia, chronic heart hypoxia is more common.
Its cause is mainly poor blood supply, and another cause is related to anemia. According to Dr. Liu, during the clinical diagnosis process, a doctor will check whether the patient’s hemoglobin is sufficient at the same time.
Chronic cardiac hypoxia symptoms: chest tightness, chest pain, and shortness of breath. If you are prone to these conditions while walking or exercising, you should be extra careful.
Many people suffer from high cholesterol and smoking, making their blood vessels increasingly narrow and causing wheezing and chest pain when they walk. Nevertheless, people often consider this a minor issue and ignore it when the symptoms disappear. Dr. Liu pointed out that if not treated immediately, after a long period of time, heart hypoxia may lead to increasing weakness when doing activities, severe arrhythmia, heart failure, and myocardial infarction.
Chronic hypoxia may also become acute, triggering myocardial infarction. Therefore, if you are prone to wheezing, chest pain, and other symptoms, it is recommended get your heart checked out, rather than relying on an oximeter to determine your blood oxygen level or ignoring the symptoms.
More Middle Aged and Male Patients
If we don’t take menopause into account, the majority of heart hypoxia patients below the age range of menopause are men. Women prior to menopause are protected by female hormones and have better cardiovascular health. In most female patients, cardiovascular diseases start to develop after menopause. Therefore, after menopause, the proportions of men and women with cardiovascular diseases become similar.
Cardiac hypoxia is more likely to occur in patients between the ages of 45 and 65, in both men and women. And it is mostly caused by the narrowing and hardening of blood vessels, which is related to aging, cholesterol and smoking.
“If a person starts smoking and eating a diet high in oil and sugar when he or she is young, after the accumulation for over 20 years, he or she will be prone to heart hypoxia, upon reaching the age of 40, and the fastigium (period when symptoms of disease are most pronounced) starts at the age of 45,” Dr. Liu said.
In order to prevent heart hypoxia, we should avoid smoking, reduce the consumption of foods high in oil and sugar, do more exercises, and avoid overworking.
5 Types of Food to Prevent Heart Hypoxia
There are also some foods beneficial to our blood vessels and blood cells.
- Foods containing soluble dietary fiber
Soluble dietary fiber can reduce the absorption of cholesterol by the intestines and excrete bad cholesterol, which helps keep blood vessels unobstructed, so the blood can flow smoothly to the tissues, avoiding local hypoxia.
Foods rich in soluble dietary fiber: oats, potatoes, pumpkins, yams, okras, mushrooms, seaweeds, cauliflowers, carrots, melons, apples, pears, bananas, kiwis, citrus fruits.
Fish is a wonderful source of high-quality protein and polyunsaturated fatty acid omega-3, which are beneficial to blood vessels and red blood cells.
Protein helps with the production of red blood cells; and omega-3 has a preventive effect on atherosclerosis, as it helps remove fat from blood vessels and stabilize atherosclerotic plaques.
An epidemiological survey in Greenland discovered that the incidence of ischemic heart diseases among Greenlanders is very low, and this is related to a diet rich in omega-3.
Fish with high Omega-3 content are salmon, tuna, mackerel, herring, trout, and sardines. We should choose wild, rather than farmed, fish in order to avoid toxins.
- Allium and cruciferous vegetables
These two groups of vegetables contain organosulfur compounds that allow blood to flow smoothly through the arteries and prevent chronic hypoxia.
Studies have found that organosulfur compounds reduce the synthesis of cholesterol in liver cells and inhibit platelet coagulation. If the ability of platelets to coagulate increases, it tends to cause blood vessels to narrow.
Organosulfur compounds may also prevent atherosclerosis and the reocclusion of treated coronary arteries.
Common allium vegetables: garlic, onions, leeks, scallions, and chives.
Cruciferous vegetables: cabbages, cauliflowers, broccolis, collard greens, arugulas, cabbages, radishes, kales.
- Meat, fish, and shellfish
Iron is an essential mineral for the synthesis of hemoglobin. Without sufficient iron, hemoglobin synthesis will be inadequate, and the amount of oxygen carried by red blood cells will be lower.
Meat, fish, and shellfish are ideal iron-rich foods, because the human body’s absorption rate and utilization rate of animal iron are better than those of plant iron.
In addition, when eating iron-containing foods, it is important to eat vitamin C-rich fruits and vegetables at the same time to promote iron absorption.
Vitamin C-rich fruits and vegetables: guavas, papayas, grapefruits, strawberries, kiwis, oranges, tomatoes.
Eggs are a very nutritious food that contains the nutrients needed to prevent anemia and produce hemoglobin and red blood cells, including protein, vitamin B6, vitamin B12, folic acid, copper, iron, and vitamin D.
Some people worry that eating too many eggs will make their cholesterol levels too high. However, a 2018 review pointed out that cholesterol in food has little effect on the body, but rather, saturated fatty acids (SFAs) increase the risk of cardiovascular diseases. A large egg (50 grams) contains only 1.56 grams of SFAs, making it a healthy and affordable food item, according to the review.
A balanced diet is a natural way to get the aforementioned nutrients. Dr. Liu shared with us that his patients have improved their heart hypoxia after taking medication, developing good dietary habits, and exercising properly.