If you Google the terms “constipation” and “heart attack,” you’ll soon come across the name Elvis Presley. Elvis had a long history of chronic constipation and is believed to have strained a lot while defecating, which led to his fatal heart attack.
We don’t know what really happened to the so-called King of Rock ‘n’ Roll in 1977. There are likely several factors that contributed to his death, and this theory is one of many.
But after this famous case, researchers became very interested in the link between constipation and the risk of suffering a heart attack.
This includes a recent study led by Australian researchers that included data from thousands of people.
Is there a relationship between constipation and heart attacks?
Large population studies show that constipation is linked to an increased risk of heart attacks.
For example, an Australian study involving more than 540,000 people over the age of 60 who were hospitalized for a variety of conditions found that constipated patients had a higher risk of high blood pressure, heart attacks, and strokes compared to patients of the same age who did not suffer from constipation.
A Danish study of more than 900,000 people from hospitals and hospital outpatient clinics also found that constipated people had a higher risk of heart attacks and strokes.
However, it was unclear whether this link between constipation and increased risk of heart attacks and strokes would hold true for healthy people outside the hospital.
These Australian and Danish studies also did not take into account the effects of medications used to treat high blood pressure (hypertension), which can cause constipation.
How about this new study?
A recent international study led by researchers at Monash University found a link between constipation and an increased risk of heart attacks, strokes and heart failure in the general population.
The researchers analyzed data from the UK Biobank, a database of health-related information on about half a million people in the United Kingdom.
The researchers identified more than 23,000 cases of constipation and took into account the effect of medications to treat high blood pressure, which can cause constipation.
People with constipation (identified through medical records or a questionnaire) were twice as likely to have a heart attack, stroke, or heart failure than those without constipation.
Researchers found a strong link between high blood pressure and constipation. People with hypertension who were also constipated had a 34% higher risk of a major cardiac event compared to those who had hypertension alone.
The study only looked at data from people of European descent. However, there are good reasons to believe that the link between constipation and heart attacks applies to other populations.
A Japanese study examined more than 45,000 men and women in the general population and found that those who defecated once every two to three days had a higher risk of dying from heart disease compared to those who defecated at least once a day.
How could constipation cause a heart attack?
Chronic constipation can cause straining when passing stool, which can lead to shortness of breath and increased blood pressure.
In a Japanese study involving ten elderly people, blood pressure was high just before defecation and continued to rise during defecation. This increase in blood pressure continued for an hour afterwards, a pattern not seen in younger Japanese.
One theory is that older people have stiffer blood vessels because of atherosclerosis (thickening or hardening of the arteries caused by plaque buildup) and other age-related changes. So their high blood pressure may persist for some time after exertion. But younger people’s blood pressure quickly returns to normal because they have more elastic blood vessels.
As blood pressure increases, so does the risk of heart disease. The risk of developing heart disease doubles when systolic blood pressure (the top number in a blood pressure reading) increases steadily by 20 mmHg (millimeters of mercury, a standard measure of blood pressure).
Systolic blood pressure has been reported to increase with straining to defecate by up to 70 mmHg. This increase is only temporary, but with persistent straining in chronic constipation, this could lead to an increased risk of heart attacks.
Some people with chronic constipation may have impaired function of the vagus nerve, which controls several bodily functions, including digestion, heart rate, and breathing.
This alteration in function can lead to abnormalities in heart rate and an overactivation of the fight-or-flight response, which in turn can lead to increased blood pressure.
Another intriguing line of research examines the imbalance of gut bacteria in people with constipation.
This imbalance, known as dysbiosis, can cause microbes and other substances to leak through the gut barrier into the bloodstream and trigger an immune response. This, in turn, can lead to mild inflammation in the bloodstream and stiffen the arteries, which increases the risk of heart attack.
What can we do about it?
Constipation affects around 19% of the global population aged 60 or over, so there is a significant portion of the population that is at increased risk of heart disease due to their gut health.
Controlling chronic constipation through dietary changes (particularly increasing dietary fiber), increasing physical activity, ensuring adequate hydration, and using medications, if necessary, are important ways to help improve bowel function and reduce the risk of heart disease.