During hot summer days, our body reacts by dilating superficial blood vessels and then the blood flow through them can be increased up to 20 times to increase heat release.
The human body reacts differently during hot summer days than usual. The superficial blood vessels dilate and then the blood flow through them can be increased up to 20 times in order to increase the release of heat. Also, the blood is redistributed, and in order to maintain a stable pressure, the heart must work harder and faster, and the blood flow to other organs (kidneys, brain, digestive tract) must be reduced. Another mechanism that is activated by thermoregulation is sweating, which creates an additional problem for the heart because minerals are lost and the blood becomes thicker. If there is already a predisposing heart condition (angina pectoris, heart failure), the health condition may worsen.
How dehydration and sweating endanger the cardiovascular system
Whether you are fishing through a hole in the ice in Antarctica or taking a selfie somewhere on the equator, one thing in your body will be the same, and that is the effort to keep the internal body temperature at around 37 degrees Celsius, of course, with slight variations.
In conditions of high temperatures, our body naturally finds ways to get rid of excess heat by sweating, but, too much sweating, creates two problems for the body:
- Dehydration occurs, which complicates the normal functioning of the cardiovascular system, the blood becomes thicker, there is a so-called hemoconcentration, which increases the risk of blood clots and adverse events, including stroke. Among other things, one of the main risk factors for the development of arrhythmias (irregular heartbeat, especially atrial fibrillation) on warm days is dehydration. Another thing that happens when we sweat excessively is the loss of precious minerals, sodium, potassium, magnesium and others, which are very important for the normal functioning of the heart and blood vessels.
Caution with therapy for hypertension and diuretics
Hypertensives and patients taking diuretics belong to two groups of people who are particularly sensitive to extreme temperatures, because of their regular therapy, which often includes diuretics, they must be especially careful:
All pressure medications, not just diuretics, can cause the body to overreact to heat. In heart patients, due to advanced atherosclerosis, the ability of blood vessels to adapt is significantly reduced. Also, due to vasodilation and dehydration, there can be a decrease in tension, dizziness and falls, which is especially dangerous in older people. Many patients know or feel this, so they call the doctor in order to correct the therapy in agreement with him.
The use of sunscreen is also mandatory
Something that is also insufficiently talked about is the influence of the sun itself, and not only high temperatures on thermoregulation.
Sunburn on the skin interferes with the mechanisms by which our body releases excess heat. That is why it is very important that everyone flies, and especially heart patients, people with diabetes, obese people and the elderly must use sunscreen every day, not only when they go to the beach.
Watch your diet and avoid alcohol, even beer
The reasons why doctors, especially in summer, recommend “lighter” meals are also clear. Eating a large amount of food, especially fatty ones, will cause the release of a large amount of energy, which is usually converted into heat, which we certainly do not need.
The reduced blood flow to the stomach and intestines also contributes to that, due to the redistribution into dilated blood vessels of the skin. Seasonal foods, fruits and salads through which we ingest larger amounts of fluids and minerals should be a mandatory food choice in the summer.
One of the biggest misconceptions is that drinking beer “rehydrates” the body in the summer. Alcohol is a diuretic, which means that it will force a person to urinate more often and at the end of the day lead to a negative water balance in the body. So, despite drinking a few bottles of beer, paradoxically at the end of the day you will be dehydrated.