More than half of all diabetics die of a heart attack: this alone shows how important good heart function is in connection with diabetes mellitus. Often, heart damage due to diabetes is detected late. Conversely, it is sometimes the case that diabetes is only detected because a patient visits his or her doctor because of heart problems. Read here about the relationship between diabetes and the heart.
What does diabetes do in the body?
Almost everyone knows that diabetes means too high a blood sugar concentration. But what exactly happens in the body when blood sugar concentration is permanently too high? The high sugar level damages the blood vessels and causes the blood to clot more quickly: the number of blood platelets (thrombocytes) increases and the mechanisms that dissolve the smallest blood clots and inhibit blood clotting are disrupted. This is referred to as impaired fibrinolysis. In addition, the blood is more viscous and sticky than normal – the experts call this: Blood viscosity is increased. It is easy to imagine that this thick, sticky blood easily attaches itself to small vessels and clogs them. These circulatory problems increase the risk of a heart attack or stroke. In addition, the composition of the blood changes – more fats are released from the body’s cells (increase in blood fat levels) and the concentration of electrolytes (sodium and potassium) shifts. Even in the cells, the excessive sugar content has an effect: Many processes such as the production of proteins, activation of immune cells or the release of hormones are disrupted at the molecular level. All this makes diabetics additionally more susceptible to infections.
Diabetic macroangiopathy
Diabetes leads to a condition called macroangiopathy, which means that all large or major blood vessels are affected by sugar levels: Arterial blockage and occlusion are the consequences. In diabetics, arteriosclerosis occurs up to ten years earlier than in non-diabetics. In the heart, the clogged arteries lead to coronary heart disease (CHD), heart pain (angina pectoris) and, in the worst case, a heart attack. Diabetics have a much worse prognosis for heart attacks, strokes and circulatory problems in the extremities. This can be explained by the fact that high blood sugar impairs the body’s repair processes, so that diabetics recover from such an event significantly worse than non-diabetics. Often, a diabetic also lacks warning of an infarction in the form of heart pain, or a so-called silent infarction occurs – an infarction without pain.
Diabetic neuropathy
In many diabetics, the sensation of pain is limited because the high blood sugar levels damage the nerves as well as the vessels – diabetic neuropathy is the result. If many nerves are affected, this is also called diabetic polyneuropathy. Often, stocking-shaped sensations occur in the feet and lower legs: Tingling, numbness and an increasing numb feeling are the most common symptoms. In the long term, this can lead to injuries to the feet going unnoticed and becoming inflamed – this is then referred to as diabetic foot.
Neuropathy interferes with heart rate
Unfortunately, it is not only the nerves in the feet that are damaged, but also the sympathetic and parasympathetic nerve fibers that make up the autonomic nervous system. At the heart, they influence the heartbeat, blood pressure and the volume of blood pumped through the heart per minute. Normally, this allows the heart to adapt to all kinds of situations: When we exercise, it beats faster and more blood is pumped through it – when we sleep, the heart rate drops. But as soon as the autonomic nervous system fails, the heart can no longer adapt to the demands of everyday life. Diabetes often leads to so-called autonomic neuropathy, which means that autonomic nerves in particular are damaged. These regulate the unconscious body processes. The consequence can be that the heart beats relatively fast even at rest (resting tachycardia, palpitations) and that the heart rate no longer adapts to the required stress. The blood pressure, which otherwise changes depending on the body position, also no longer adapts to sitting, standing or lying down (orthostasis). The risk of atrial fibrillation is increased, and some sufferers also experience heart palpitations and heavy sweating.
Women with diabetes more likely to be affected by heart failure
The worse the blood glucose control, the higher the risk of developing cardiovascular disease. Gender may also play a role. In type 1 diabetes in particular (but also in type 2 diabetes), women are more likely than men to be affected by heart failure (cardiac insufficiency), according to one study. Those affected have an irregular pulse, have difficulty breathing at night, or experience shortness of breath when exerting themselves, such as climbing stairs. Other studies have shown that women with diabetes also have an increased risk of stroke or coronary heart disease. Age at the time diabetes develops also plays a crucial role. The earlier you develop type 2 diabetes, the more likely you are to develop heart problems, one study found.
How do you recognize heart involvement?
It is the combination of impaired pain sensation and a heart that cannot be influenced by the nervous system that can cause a diabetic heart to be overly stressed in the presence of atherosclerosis and narrowed coronary arteries. Normally, heart pain would occur, one would stop the stressful activity – heart damage is avoided. In the diabetic, however, no pain occurs and, in the worst case, a silent heart attack occurs, unheralded by any warning signs.
How do you diagnose heart involvement in diabetes?
An increase in heart rate at rest can be detected by taking the pulse. However, measuring the heart rate once is not particularly informative, because many people are agitated when they visit the doctor. For this reason, an ECG and, above all, a long-term ECG are used to check the extent to which the heart rate decreases during periods of rest. An exercise ECG is used to examine the extent to which the heart rate and the activity of the heart change under a defined load (usually cycling on an ergometer) and whether the ECG shows changes in the heart rate and the blood flow situation. If the findings are conspicuous, a cardiac catheter examination can be used to clarify precisely whether and to what extent there is arteriosclerosis of the coronary vessels.
Heart problems in diabetes: what can the doctor do?
As soon as you are diagnosed with heart damage, it is particularly important to protect the heart with medication, in addition to the best possible blood sugar control. This involves using beta blockers to lower the heart rate and ACE inhibitors to normalize blood pressure and thus help the heart do its job. Anticoagulants such as low-dose acetylsalicylic acid prevent tiny blood clots from forming and clogging arteries.
What can you do to lower your own risk?
Everyone should strive to avoid the risk factors that can lead to diabetes. Obesity, in particular, plays a key role in the development of diabetes. It causes the body’s organs to demand more and more insulin until they allow blood sugar into the cells. They become resistant to insulin, so to speak. This insulin resistance gradually develops into the most common form of diabetes, type 2 diabetes, which is also trivially called adult-onset diabetes. These painless diseases – obesity and insulin resistance – together with high blood pressure and dyslipidemia are known as the “deadly quartet” – their pitfall lies in the fact that sufferers often fail to notice them or, due to the lack of acute suffering (no pain, no acute restriction of quality of life), are unwilling to do anything consistently to combat the disease. Thus, it is not at all uncommon for type 2 diabetes to be diagnosed only after several years.
Preventing heart problems and diabetes
In addition to increasing physical activity and abstaining from nicotine and alcohol, a healthy diet and reduced intake of table salt are ways to protect yourself – and improve your overall quality of life. If you have diabetes, you should have your family doctor check your heart at least once a year with an ECG and stress ECG – because your heart may not be able to draw attention to itself through discomfort. Pay particular attention to improving blood sugar levels, blood pressure and cholesterol levels to reduce the risk of heart problems or stroke.
