How does cold weather affect my heart?

Farhad Rafii, MD
Cardiology (Cardiovascular Disease)
Seasonal climate change can be a heart attack trigger. In colder climates, individuals tend to be more sedentary, so when they are faced with a snowstorm and need to shovel snow, a fairly arduous physical activity, they are placing a demand and strain on the heart muscle that may cause a heart attack. Additionally, your heart has to work overtime to maintain core body temperature whenever you leave a warm house and enter a cooler temperature outside. As a result, the heart has to work more, blood vessels constrict from heat being lost to the environment and these changes in the heart and blood pressure can be triggers for heart attack.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Frigid temperatures thicken your blood and constrict your arteries, which elevates your blood pressure. Those changes are a one-two punch for your heart, leaving it more vulnerable to a heart attack. Add overexertion (such as shoveling the driveway), and you’re primed for a visit to the ER. So take it easy before starting physical activity, and warm up slowly. If you must do hard work, such as shoveling snow, work in small intervals, taking breaks often. Better yet, if you are over 50 or know you are at risk for heart disease, ask someone else to do it, or invest in a snow blower.
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When outdoor temperatures drop, you may not realize it, but your heart has to work harder. In fact, according to the American Heart Association, heart failure causes most deaths from hypothermia - a dangerous condition in which the body’s temperature falls below normal. Additionally, cold temperatures increase heart attack risk, though the reasons are not fully understood.
If you have known heart disease or are simply interested in safeguarding your heart’s health, learning about the effects of cold weather on the heart can help you keep wintertime safe and enjoyable.
Your Heart in the Cold
The heart is a fist-sized muscle that pumps blood through your arteries to organs and tissues throughout your body. When temperatures drop, the heart has to work harder to help maintain your body’s core temperature. Additionally, walking through heavy snow or lifting shovels full of snow can be unexpectedly strenuous work for anyone who only completes those tasks occasionally. Some researchers think cold weather may influence the human body in other ways (such as hormones or blood vessel constriction) to also increase the likelihood of a heart attack.
If You Have Heart Disease
Cold weather can be dangerous for anyone, but it is particularly dangerous for people with existing heart disease. Even if you do not have known heart disease, it is still important to bundle up with layers of clothes when going outside, wear a hat to reduce heat loss from your head, and to go slowly when shoveling or doing other physically challenging tasks. If you know you have heart disease, the same warnings apply, but much more strongly. Before cold weather strikes, ask your physician about safe levels of exposure to the cold and what activities are likely okay - and which should be left to someone without heart disease.
Hypothermia and heart attack are both medical emergencies. If you suspect either, dial 9-1-1 immediately.
Heart attack symptoms
  • Chest discomfort (Remember: not all people with heart attacks have chest pain.)
  • Pain or discomfort in one or both arms, the back, neck, jaw or stomach
  • Shortness of breath with or without chest discomfort
  • Breaking out in a cold sweat, or feeling nauseous or lightheaded   
Hypothermia symptoms
  • Exhaustion or drowsiness
  • Shivering
  • Confusion
  • Memory loss
  • Fumbling hands
  • Slurred speech

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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.