Heatwaves and Chronic Illness: Heart Attack and Stroke Risk
A heatwave puts extra strain on the heart, blood vessels and kidneys. Doctors explain who is most at risk and how to spot the early signs of heatstroke in time.
- During heatwaves the risk of heart attack, stroke, angina and blood clots rises.
- The most vulnerable are older people, those with chronic conditions and people who work outdoors.
- Doctors advise at least 2 liters of fluid a day, ideally plain water.
- Signs of heatstroke: red, hot skin that does not sweat, dizziness, severe headache, fainting.
Why is it always in summer that we hear someone collapsed in the street? The answer is simple: high temperatures put serious strain on the heart and blood vessels. When the thermometer climbs above thirty degrees, the body works to cool itself, the heart beats faster, blood vessels widen, and the blood thickens because of fluid loss. For a healthy person that is demanding but bearable. For someone who already has a chronic illness, it is a situation that calls for real caution.
During a heatwave, doctors record more cases of heart attack, stroke, angina and blood clots. The reason is exactly that added strain. When you lose too much fluid, the blood thickens and clots form more easily. At the same time, the heart has to work harder to keep the body at a normal temperature. For someone with a weakened heart or high blood pressure, that extra effort can be too much.
Who is most at risk during a heatwave?
Not everyone faces the same risk. Older people are especially vulnerable, because the sense of thirst fades with age, so they do not drink enough water even when the body needs it. Then there are people with chronic conditions, those with heart and kidney disease, diabetes or high blood pressure. Heat puts extra load on the kidneys, and people with bronchial asthma may see their symptoms worsen.
A third high-risk group is people who work outdoors, on construction sites, in farming or in traffic. They spend hours exposed to the sun and physical effort during the hottest part of the day. The Red Cross and doctors therefore recommend avoiding heavy work and exertion between 11 a.m. and 5 p.m., when the sun is strongest. If the work cannot be postponed, frequent breaks in the shade and a constant supply of fluids are essential.
The practical advice is simple: do not wait until you are thirsty. Thirst is already a sign that the body has started to lose water. It is better to drink a little and often throughout the day than a large amount at once. Avoid alcohol and too much coffee, since they pull even more fluid out of the body.
How can you recognize heatstroke in time?
Heatstroke is a condition in which the body overheats and can no longer cool down, and it is a medical emergency. The first signs to know are red, hot skin that does not sweat, a severe headache, dizziness, a racing pulse, nausea and confusion. In more serious cases the person faints.
If you notice these signs in yourself or someone nearby, act at once. Move the person into the shade or a cooled room, remove excess clothing and cool them with damp cloths, especially the neck, armpits and groin. If the person is conscious, give them water in small sips. If there is fainting or confusion, or if the condition does not ease, call emergency services without delay.
Prevention is still the best protection. On the hottest days stay in the shade, wear light, pale clothing, use a hat and keep out of direct sun. If you take medication for blood pressure, your heart or blood sugar, talk to your doctor about whether anything should change in hot weather, since some drugs affect hydration and blood pressure.
Heatwaves cannot be avoided, but the risk can be reduced. Have you had enough water today, and do you know what to do if someone beside you collapses in the sun?
