How Hot Weather and Humidity Impact Your Heart and Blood Pressure and How to Stay Safe

Hot, humid summer days can make anyone feel tired, sluggish, and uncomfortable. But if you have high blood pressure (hypertension) or a heart condition, sweltering weather can pose an even bigger challenge.

To keep your body running smoothly year-round, see John Terzian, MD, FACC, and the team at Bridgewater Primary Care & Cardiology, LLC. We specialize in helping patients actively manage their blood pressure and heart health through all seasons of life.

In this post, we explore how hot weather and humidity impact your cardiovascular system and offer practical tips to stay safe as the temperature rises. Here’s what you should know this summer.

How your body responds to heat and humidity

When it’s hot and humid, your body goes to work to cool itself down and maintain a safe internal temperature. One strategy is to increase blood flow to your skin, allowing heat to dissipate into cooler external air.

However, the effort it takes to pump this extra blood (twice the amount per minute compared to a cooler day) can stress the heart. And if the outside air is close to or higher than your core temperature, this heat transfer can’t happen effectively.

You also regulate heat by sweating. As sweat evaporates from the skin, your body temperature decreases. Except when humidity levels climb, the air is already so full of moisture that sweat can’t evaporate as efficiently — it just drips off, providing little to no relief and draining your body of vital fluids and electrolytes.

The added strain for heart conditions and high blood pressure

Although a healthy individual can typically handle this extra demand on their system, hot weather becomes a much bigger concern if you’re managing a heart condition. The combination of increased blood flow and dehydration can cause blood pressure to drop too low, leading to dizziness, fainting, and falls.

If you have hypertension, your blood vessels may be unable to expand enough to release heat. This forces your heart to pump even harder, dangerously increasing your blood pressure.

Certain medications for these conditions can also affect your body’s ability to regulate its temperature or fluid levels. When it can no longer adequately cool itself, you run the risk of heat illness, including heat stroke.

Essential tips for protecting your health in the heat

Staying cool in the heat and humidity isn’t just about comfort. Even if you’re generally healthy, understanding how to protect your cardiovascular system becomes crucial in extreme temperatures. Here are our tips for staying safe this summer:

Prioritize hydration

Don’t wait until you’re thirsty — sip water steadily throughout the day. Staying hydrated helps your heart pump efficiently and can prevent blood sugar fluctuations. Steer clear of alcohol and caffeinated beverages, as they can dehydrate you.

Seek out cool spaces

Air conditioning is key on hot, humid days. If you don’t have it at home, head to a public cooling center, library, mall, or another air-conditioned place. Cool showers and baths can also offer quick relief and help bring your body temperature back down.

Time your activity

Avoid strenuous activities during the hottest parts of the day, usually between 10 am and 4 pm. If you must be outside, try to plan the most physical tasks for early morning or late evening when it’s cooler.

Be alert to warning signs

Pay close attention to how you feel. Early signs that your body is struggling with the heat may include fatigue, mild dizziness, or increased sweating. If you notice these symptoms, move to a cooler place, hydrate, and rest. 

Be on the lookout for more serious symptoms, such as a severe headache, confusion, rapid pulse, or a sudden change in sweating (either heavy or none at all), which may require immediate medical attention.

For personalized guidance on keeping your heart healthy, schedule a consultation at Bridgewater Primary Care & Cardiology, LLC, in West Bridgewater, Massachusetts. We offer same-day appointments for urgent concerns.