How Hot Weather Affects the Heart

Caitlyn Begosa

| 3 min read

Caitlyn Begosa is a corporate communications intern ...

When the weather gets warmer and sunnier, it’s hard to stay inside. However, the rise in temperature can cause many issues for the heart, especially for those who live with heart disease.
Hot temperatures force many vital organs, such as the lungs, kidneys and heart, to work overtime to cool down the body. This added work creates a significant amount of strain on the heart.

Radiation and evaporation

The body always needs to keep a certain temperature, so an increase in hot weather triggers the body to cool itself down. The body regulates its temperature in two ways: radiation and evaporation. Both processes involve the cardiovascular system and can cause extra stress on the heart:
  • Radiation is when the body’s heart rate goes faster to increase the blood flow to underneath the skin. The blood is moved away from major organs, where it’s hotter, to a cooler area. Then, the body radiates heat into the surrounding atmosphere to cool its internal temperature. However, this process can increase the body’s blood pressure and stress on the heart. 
  • Evaporation is when the body sweats, and the sweat evaporates to alleviate the body from heat. Although this cools down the body, it loses water and many important minerals such as sodium and potassium. Because of this loss, blood volume reduces and results in dehydration, which can cause heart stain. 

Increased strain on the heart

For both radiation and evaporation, the heart must work harder to keep the body cool. On a hot day, the heart beats faster and circulates two to four times more blood per minute than on a colder day, resulting in stress for the heart.
Heart strain can increase the chances of:
  • Higher blood pressure
  • Heart attacks
  • Irregular heartbeats
  • Heart failure
Individuals with preexisting heart conditions or older adults are at a higher risk of these issues when it’s hot outside.

Safety tips for hot weather

It’s important for everyone to take extra precautions in the hot weather to keep your heart safe and healthy. Here are some tips to beat the heat:
  • Stay hydrated: Drink water before, during and after going outside, and snack on food with a high-water content and electrolytes.
  • Avoid beverages that will dehydrate you such as coffee, tea and alcohol.
  • Dress in lighter-toned colors and breathable fabrics like cotton and linen. Most importantly, wear sunscreen to protect your skin from harmful UV rays and sun damage.
  • Exercise earlier in the morning or in the evening when it’s cooler outside.
  • Take breaks indoors or in a shady area when outside for extended periods of time. These breaks are a great time to hydrate and rest.
  • Know the signs of excess sun exposure, heat exhaustion and stroke.
Talk to your doctor about how to stay safe and healthy during the summer if you have a heart condition, or take certain heart medications as they can exacerbate the effects of the heat on your body.
MI Blues Perspectives is sponsored by Blue Cross Blue Shield of Michigan, a nonprofit, independent licensee of the Blue Cross Blue Shield Association