Risk Factors

In principle, anyone  can suffer a stroke – whether he or she is young or old. Stroke is not a disease that affects only "old people". Every fourth person affected is of working age, an estimated 5% of whom are even younger than 40.
Moreover, people whose relatives have suffered a stroke carry an increased risk of suffering a stroke. Certain risk factors are hereditary. Age and genetic predisposition are risk factors that cannot be influenced, but others can be changed or treated.
These include:

High Blood Pressure

High blood pressure is also called arterial hypertension. Arterial hypertension is defined as a permanent increase of systolic and diastolic blood pressure (maximum and minimum blood pressure value).
Increased values measured once or occasionally do not necessarily mean a high blood pressure. For diagnosis, regularly increased measurement values ​​are crucial. The optimum blood pressure is 120/80 mm Hg (according to the target values ​​set by WHO). The limit for arterial hypertension for adults is 140/90 mm ​​Hg. Hypertension values ​​vary heavily:

  • moderate hypertension:  values ​​are permanently above 160/100 mm Hg
  • severe hypertension:  values ​​are permanently above 180/110 mm Hg  

High blood pressure is a major risk factor for stroke. It leads to thickening and stiffening of the blood vessels (arteriosclerosis). Patients with high blood pressure therefore suffer a stroke more often than people without high blood pressure. High blood pressure increases the relative risk of suffering a stroke six- to eight-fold compared to a person without hypertension. The level plays a special role, because with the level of blood pressure, the risk of stroke increases. Treatment of high blood pressure, however, leads in turn to a significant risk reduction compared to untreated patients.

A major problem is that high blood pressure is still too rarely recognized. Usually the person concerned does not notice high blood pressure because it does not hurt. It is therefore important to check blood pressure regularly and initiate treatment if necessary. Everyone should know his or her blood pressure.


Cigarette smoking is a significant risk factor for stroke, and risk increases with the number of cigarettes smoked per day and in total over the number of years. Smokers have a relative stroke risk 1.5 to 2 times higher than non-smokers. The negative effects of smoking are manifold:

  • Smoking fosters the calcification of blood vessels (atherosclerosis).
  • Smoking causes the nervous system to release the stress hormones adrenaline and noradrenaline, thereby narrowing the blood vessels. This in turn leads to high blood pressure. The constriction of blood vessels limits the intake of vital substances.
  • Smoking also reduces the amount of oxygen which is transported by the red blood cells in the body. The amount of oxygen available to the brain (and other parts and other parts of the body) decreases. Due to oxygen deficiency the brain signals the bone marrow to produce more red blood cells. The increased production of red blood cells leads to "blood thickening" and blood flow properties are affected; the blood is thicker. This reduces the blood flow in addition to the constricted vessels.
  • Smoking increases the tendency of the blood to coagulate. This increases the risk of clot formation in the blood.  
  • Finally, smoking leads to alterations of fat metabolism.

Therefore please quit smoking! When you stop cigarette smoking your stroke risk factor is reduced considerably.

Alterations of Fat Metabolism

Alterations of fat metabolism increase the risk of stroke. Blood fats are deposited in the artery walls and enhance the development of artheriosclerosis.

Pay attention particularly to cholesterol, because with total-cholesterol levels above 240 mg/dl the risk of stroke increases by two-and-a-half times. The total-cholesterol level should be less than 200 mg/dl. This approximate value is particularly important if the "bad" part of the cholesterol (low density lipoprotein/LDL) is increased and the "good" part of the cholesterol (high density lipoprotein/HDL) is reduced.

Everyone should know their cholesterol level and, if necessary, deal with it by making changes in diet or medication. Diet has a major impact on cholesterol levels. As a guideline, the consumption of animal fats should be restricted or replaced by vegetable fats. Sports and regular exercise also have a positive effect on blood lipid levels.

Smoking, on the other hand, has negative effects on blood lipid levels.

Obesity and Lack of Exercise

What is referred to as "fat" or "skinny" is often determined by fashion and zeitgeist. It is difficult to tell the ideal weight for a specific individual. Nevertheless, it is possible to determine which body weight at which height corresponds to the statistical average, promotes a long life expectancy, and improves your health.
Obesity is defined as an excessive high body weight in relation to body size. This ratio is calculated using the so called "body mass index" (BMI). The BMI results from the body weight in kilograms [kg] divided by the square of the height in meters [m2]. The recommended BMI depends on age and is summarized in the following table.

Age group in years Desirable BMI [kg/m²]

Being overweight is a risk factor for many diseases. It leads to high blood pressure, burdens the bones and joints and increases the risk of diabetes. For an overweight individual the relative risk of suffering a stroke is around one to two times higher than the risk for a person of normal weight.
Therefore: Get moving! This is one of the most important measures to reduce obesity. Basically, endurance sports are helpful. Start slowly, but: Get Started!


Diabetes is a major risk factor for stroke. Diabetes is a collective term for many different forms of metabolic disorders which have in common that the blood sugar level is too high after eating and after fasting. In patients with diabetes the blood vessel walls are affected. They thicken and thus hinder the blood flow. The thickening of vessel walls is mediated among other things by atherosclerosis and is exacerbated by all forms of diabetes including, for example, "adult onset diabetes".

The risk of stroke is two to three times higher in people with diabetes than in healthy people. Initially, many people with diabetes do not realize that they have the disease. Diabetes does not hurt, so the disease is often noticed late. The most common form is adult onset diabetes.
A disease can only be treated if it is detected. Regular check-ups testing for diabetes are therefore useful.

Cardiac Arrhythmias (Atrial Fibrillation)

Cardiac arrhythmias are perturbations in the normal cycle of the heartbeat, more specifically in the heart muscle excitation. The heart beat is no longer regular. One particular type of heart rhythm disorder, atrial fibrillation, entails a significant increase in the risk of stroke: It is at least five times higher. About 5 % of all people with atrial fibrillation have a stroke each year. If the patient suffers from other diseases such as coronary heart disease or cardiac insufficiency additionally, the risk increases by a factor of two to three. The presence of rheumatic heart disease is particularly serious. In atrial fibrillation with rheumatic heart damage, the risk increases seventeen-fold. The data from scientific studies also suggests that especially elderly people with atrial fibrillation are at increased risk of stroke.

Atrial fibrillation is common: 2-3% of people between 40 and 65 years suffer from atrial fibrillation and about 5% of those aged over 65 years.

By feeling your pulse at the wrist you can easily determine whether or not the heartbeat is regular. Many species of cardiac arrhythmias can be detected with EKG. Again, many people do not know that they have cardiac arrhythmias. Only an examination can bring certainty.

In the prevention of stroke with atrial fibrillation, drugs are used to thin the blood and prevent the formation of blood clots. These so called oral anticoagulants can be very effective in preventing stroke or systemic embolism.

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