How does hot weather affect my heart?

Farhad Rafii, MD
Cardiology (Cardiovascular Disease)
When it is hot outside, people, especially seniors, are more prone to developing dehydration. When a person gets dehydrated, blood becomes concentrated and the heart rate has to rise to meet the body’s demands and try to lower the body’s temperature. This could trigger a heart attack. In warm temperatures, especially when it gets to the triple digits, it is generally recommended that the elderly avoid prolonged exposure to sunlight. Use sun umbrellas, stay hydrated and try to stay indoors as much as possible during the early afternoon hours of extreme heat.
You probably know that long periods of extremely hot weather can be life threatening, but you may not understand why - or know where your heart fits in the picture. Whether you have heart disease or not, it’s time to think about how you can protect your heart and still enjoy summertime.
Your Heart in the Heat
The heart is a fist-sized muscle that pumps blood through your arteries to organs and tissues throughout your body. When ambient temperatures rise, the heart has to beat faster and work harder to pump blood to the surface of your skin to assist with sweating to cool your body. If your body cannot cool itself enough, strain is put on the heart, and organs can begin to suffer damage - a potentially fatal condition known as heat stroke.
If You Have Heart Disease
Anyone can get heat stroke, but people with heart disease and other cardiovascular diseases are at greater risk. If you have heart disease, your heart may not be able to work harder in the heat to maintain cooler body temperatures. Additionally, diuretics to reduce water in the bloodstream are prescribed for many heart conditions, as are beta-blockers. Each of these medications can reduce a person’s ability to cool off in the heat. If you have been prescribed diuretics, ask your physician about safe levels of water to drink for hot conditions versus milder temperatures.
Symptoms of Heat Stroke
Heat stroke is an emergency. If you experience the following symptoms, apply cool water to your skin immediately and seek medical help.
  • High fever
  • Hot, dry skin without sweating
  • Pounding pulse
  • Dizziness
  • Nausea and/or vomiting
  • Confusion
  • Unconsciousness
If you experience heavy sweating with cool, clammy skin, along with symptoms such as fatigue, nausea, or fainting, you may have heat exhaustion - a form of heat sickness that can lead to heat stroke. Getting out of the heat immediately, applying cool water to your skin, and drinking cool (not cold) water can help you stop heat exhaustion before it worsens.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.