How diabetes could creep into your heart

Sixty-eight-year-old TR Rohini’s blood readings were borderline diabetic, but aside from some muscle discomfort she was happy she didn’t need to see any doctor.

“But when I noticed a breathing problem during the first Covid-19 lockdown, we decided to consult a doctor,” says the resident of Idukki, Kerala. “A burning sensation in the chest and dyspnoea led to some elementary tests including angiography. But the angiography revealed three blockages that needed immediate care. Angioplasty was done the same day. Within two days, I was diagnosed with type 2 diabetes.”

Since then, Rohini has quit eating sugar and also limited her carbohydrate intake as per doctor’s instructions.

Diabetes and heart disease are closely linked. Diabetes doubles the risk of developing heart disease or having a stroke quite early in life. The longer you have diabetes, the more likely you are to develop heart disease.

But the good news is you can reduce your risk of heart disease and improve your heart health by changing your lifestyle habits. These changes will also help you manage your diabetes better.

Diabetes and heart failure

Over time, high blood sugar levels can harm the blood arteries and nerves that control the heart. Diabetes is more likely to be associated with other illnesses such as high blood pressure and high cholesterol, which raise the risk of developing heart disease.

High blood pressure increases the force of blood through the arteries and can cause arterial walls to deteriorate. The risk of heart disease can significantly increase if a person has both high blood pressure and diabetes. Too much low-density lipoprotein (LDL or ‘bad’ cholesterol) in the bloodstream can cause the formation of plaque, which damages the artery walls.

High triglycerides (blood fat) and low high-density lipoprotein (HDL or ‘good’ cholesterol) or high LDL are likely to contribute to artery hardening.

Many people develop cardiovascular disease (all diseases affecting the heart and blood vessels) as they age, but this is avoidable.

A healthy lifestyle, especially when followed since a young age, can help prevent cardiovascular disease. Lifestyle changes and medications can halt heart-harming trends such as high blood pressure and high cholesterol. Cardiovascular disease tends to strike people with diabetes earlier than healthy people.

Over the course of an average lifetime, the heart beats about 2.5 billion times, pumping millions of gallons of blood throughout the body. This constant flow carries a variety of vital cells as well as oxygen, fuel, hormones and other substances. Additionally, it removes metabolic waste. Essential processes fail when the heart stops, some of them almost immediately.

Heart failure has been identified as a common consequence of diabetes, with a prevalence of up to 22 per cent in diabetics, with an increasing incidence rate.

Dr V Mohan, a veteran diabetologist and director of diabetes research at the Madras Diabetes Research Foundation, says diabetes can affect the heart in many ways. “Coronary artery disease, which leads to heart attacks, is much more common in people with diabetes,” he told Happiest Health. “People with type 2 diabetes can get heart disease at a younger age and it can be more severe, while people without diabetes may get one or two vessels blocked. It is more common in people with diabetes to have three or more vessels getting blocked. The severity of the blocks can also be more.”

Dr Mohan explains it in this way: complications among people without diabetes occur at the age of 60 or 65 and can happen among those with diabetes at 45 or 50. “Moreover, diabetes can affect the heart muscle directly,” he says. “This is called diabetic cardiomyopathy. This can increase the incidence of heart failure among people with diabetes, which is two to three times higher than in people without diabetes.”

Diabetes can also affect the heart rhythm because of cardiac autonomic neuropathy. So, the heart rate may either go down or, more commonly, it may increase. “We call it resting tachycardia,” he says. “When the heart rate increases, the heart unnecessarily beats many times extra in a minute. For example, if the heart beats 60 times a minute or 100 times a minute, the same amount of blood is sent out from the heart. So those extra 40 beats per minute are, in a sense, a waste as far as the body is concerned, and it can lead to the heart eventually getting worn out.”

Looking at it another way, if one does the simple math, 40 times per minute into 60 times per hour into 24 times per day into 365 times a year, one will realise that millions of times the heart is beating extra unnecessarily — with no benefit.

ABC principle

It is possible for people with diabetes to prevent heart disease. But for this, Dr Mohan says, they should follow the ABC principle:

• A — A1c or glycated hemoglobin, a measure of the control of diabetes over the last three months. This must be maintained under very good control (i.e., at least about 6 per cent)
• B — blood pressure. It must be maintained as normal as possible (preferably around 120/80)
• C – cholesterol. Particularly the bad cholesterol, which must be kept under control

Yoga, relaxation, pranayama, etc. can help to improve health and keep the heart healthy.

A heart-healthy diet comprises plenty of green leafy vegetables and some fruit, an overall reduction in carbohydrates, an increase in the protein content of the diet and healthy fats.

Regular exercise is also important. It can be in the form of walking, jogging, swimming, cycling, dancing or another form of exercise. Resistance training and some flexibility exercises will also be beneficial.

“Needless to say, smoking is one of the important causes of heart attacks, and this must be completely avoided by people with diabetes,” says Dr Mohan. “Moderation in alcohol intake is also needed.”

Heightened risk

Dr J Amalorpavanathan Joseph, a veteran vascular surgeon who established and headed the Tamil Nadu government’s organ transplant authority, says diabetes can affect every organ, right from the eye to the foot.

“If it is the heart that takes the hit from diabetes, it weakens the heart cells, so the heart becomes enlarged,” he says. “Secondly, it also causes blocks in the heart. Third, it weakens the vessel walls — so the heart becomes dilated like a cycle tube. So, all three are possible challenges before the heart if there is diabetes.”

Dr Jospeh, who currently works with MGM Health Care, a multi-speciality hospital in Chennai, says high blood pressure (hypertension) increases the strain on the heart. So, heart failure occurs very early. Hypertension also produces blocks in the heart vessels and weakening of the blood vessels — leading to an aneurysm, which is the dilatation of the heart system like a cycle tube.

“It can happen in hypertension also,” he says. “So, both hypertension and diabetes are very bad for the heart. Around 30 to 40 per cent of people with heart problems will have diabetes or hypertension. Besides heavy smoking, these are the major reasons for cardiovascular diseases. Compared to these, congenital diseases or heart diseases developed during pregnancy are less than 10 per cent.”

Dr Joseph says lesser intake of salt and sugar, fewer carbohydrates, more exercise and no smoking are the lifestyle changes advised to people with diabetes heart disease.