Status: 28.05.2024 09:39 a.m. | from North German Broadcasting logo

Circulatory failure and heat stroke are life-threatening consequences of prolonged heat. In older people, the cardiovascular system is often overwhelmed. People who take blood pressure medication and other drugs are at risk.

Extreme temperatures are bad for our health. In many older people, the body’s cooling systems no longer work as well and those who do not drink regularly risk dehydration.

Cardiac arrhythmias and shortness of breath due to the heat

But even younger and healthy people can be overtaxed by persistent high temperatures. Circulatory failure, cardiac arrhythmias and shortness of breath are dramatic consequences that often lead to emergency hospital admissions. Those affected often include people who already suffer from heart or respiratory diseases or who take certain medications that increase the risk of heat illness.

Symptoms of overheating

The first symptoms of gradual overheating are a hot, red head, swollen legs, dizziness, fainting, nausea, headaches, exhaustion, shortness of breath and falling blood pressure.

Elderly people, those with chronic illnesses and parents of children in particular should pay attention to these symptoms on hot days and see a doctor in good time. In the worst case scenario, there is a risk of heart attack or kidney failure.

Heat stroke causes heat build-up throughout the body

Heat stroke is an acute threat to life and is often preceded by heat exhaustion. When exposed to heat for a long time, the body’s own cooling systems are put under a lot of strain. The body tries to release heat by widening the vessels in the arms and legs. This can cause blood pressure to drop sharply. Fluids and minerals are also lost through sweat. This is particularly problematic for people who have to do physical work or for older people, who often already have problems with their water balance. Even if just two or three percent of the body’s fluids are missing, physical and mental performance is limited. When the first symptoms of heat exhaustion appear, many people do not necessarily think that they are a result of the high temperatures:

  • malaise
  • languor
  • aggression
  • Headache
  • general muscle weakness
  • fatigue
  • thirst
  • dizziness

At the beginning, as long as the cooling systems are still working, the skin is still rosy, warm and sweaty. But with continued overload and dehydration, sweat production stops. This is why the skin later has less blood flow, is pale, dry and rather cold. The person may even shiver. First aid measures are:

  • Bring into the shade, to a well-ventilated, temperate place
  • Lay person down, legs up, cool skin only if warm
  • isotonic drinks (“sports drinks”) are enough
  • Get help: Family doctor / Emergency medical service 116117 / Emergency services
  • If you feel confused or drowsy, call emergency services on 112

Sport and exercise in hot weather: risk of heat stroke

The danger of physical exertion in hot weather is often underestimated. When muscles move, they generate a lot of heat, which the body must release to the outside using its cooling systems. However, if two systems, the movement system and the cooling system, need to be supplied with full power at the same time, the cardiovascular system and energy reserves can quickly become overtaxed. Direct sunlight when working outdoors can increase the risk of heat stroke.

Dangers for people with pre-existing conditions

But even people who sit in armchairs at home can suffer from heat stroke if it is too warm in the attic for days and there is no cooling down and therefore no rest at night. Older people who live alone are at greatest risk. As people get older, their thirst decreases, many drink too little, and already have problems with their water balance, electrolytes or kidneys. The smallest changes have major consequences. They quickly become weak and confused, then forget to drink more – a vicious circle.

People with reduced sweating, as occurs in some skin diseases, are particularly at risk of heat-related illnesses. What is little known is that a whole range of medications can contribute to heat build-up, and some psychotropic drugs inhibit sweating. Anyone who has to take medications from the following list regularly should be aware of the side effects.

  • Antidepressants
  • Neuroleptics
  • Antihistamines
  • Diuretics
  • laxative
  • Thyroid hormones

Blood pressure and diabetes medications: adjust dose

In hot weather, not everyone can tolerate the usual dose of medicines such as Blood pressure lowering drugs or insulin. The effect of the medication may be stronger or weaker than usual. Therefore, those affected should adjust their intake to the weather conditions after consulting their doctor. It is important not to intensify the negative effects of the heat through treatment, for example water tablets (diuretics).

Cardiac arrhythmias due to mineral deficiency

When you sweat, you quickly lose several liters of fluid – and with it table salt, potassium and magnesium. A lack of these minerals can change the heart cells in such a way that cardiac arrhythmias occur more frequently.

More Gastrointestinal infections due to increased blood flow to the skin

In hot weather, the blood flow to the skin is increased, but other organs – such as the digestive organs – receive less blood. This increases the likelihood of contracting a gastrointestinal infection. Because of the reduced immune system, the infection can last longer than at other times of the year.

Pay attention to regular urination

On hot days we lose up to two liters more water than usual. And that must be replenished. Many people misjudge the right amount to drink. A sure sign is the lack of urge to urinate: if you hardly have to go to the toilet in the heat, you have not drunk enough. The color of your urine when you go to the toilet should definitely be checked. On the other hand, if you are only allowed to drink a certain amount due to heart or kidney disease, you should urgently discuss with your doctor how much you should increase your drinking. Only with enough water can the body compensate for the heat without being damaged.

Body’s own cooling systems: Increased blood circulation

High outside temperatures put a strain on the body’s own cooling systems. Our body only functions at a core body temperature of 37 degrees Celsius plus or minus half a degree. To prevent further heating, the body has to release the excess heat that affects it from the environment. To do this, the skin on the arms and legs receives more blood and the veins expand. Blood that flows just below the surface can release heat through the skin. This cools the body down. But the dilated veins in the arms and legs cause blood pressure to drop and the heart has to work harder.

Sweating is the body’s second vital reaction to rising temperatures. How convenient that the skin already has a good blood supply and regulates the fluid supply to the two to three million sweat glands that are distributed throughout the body. When needed, they secrete a secretion of water, salts, amino acids and urea. The fluid evaporates on the surface of the skin and draws heat from the skin, causing the body temperature to drop. The body’s own air conditioning system needs a lot of energy, and additional physical exertion can quickly lead to overload on hot days. This is why the heat is particularly dangerous for old people and those with pre-existing illnesses, because the body cannot also fight diseases, for example.

Special case of sunstroke affects the head

Sunstroke is a special case among summer emergencies. When the sun’s rays hit the unprotected head over a long period of time, they can irritate the sensitive meninges that lie directly under the thin skull bone.

The head is often bright red and very warm, while the rest of the body is at a normal temperature. Symptoms such as dizziness, headaches and vomiting can also only appear after being outside, for example in the evening. As a first aid measure, it is recommended to seek shade, cool down and drink plenty of fluids.

Further information

A young woman dressed in sporty clothes holds her hand to her forehead and a water bottle in the other hand. © Panthermedia Photo: tomwang

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A woman in a bikini refreshes herself under an outdoor shower. © imago/imagebroker/obermeier

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NDR Television | Visite | 28.05.2024 20:15