Hot weather can place extra stress on the body, especially for older adults and for people with high blood pressure or heart disease. When temperatures rise and humidity is high, the body works harder to cool itself. Blood flow increases to the skin to release heat. As a result, the heart may beat faster and pump more blood than usual. This added strain can affect blood pressure and heart function.

Heat and humidity can also increase fluid loss through sweating. When the body loses too much fluid, dehydration can occur. Dehydration lowers blood volume, which can cause blood pressure to drop. This may lead to dizziness, weakness, confusion, or fainting. At the same time, dehydration can also cause blood pressure to rise. When fluid levels are low, the body may hold on to sodium and tighten blood vessels in an effort to protect itself. This can raise blood pressure, especially in people who already have hypertension.

Certain individuals are at higher risk during hot weather. This includes adults over age 50, people who are overweight, and those with heart, lung, kidney, or circulation problems. People who take medications such as diuretics or blood pressure medicines may also be more sensitive to heat. Women who are experiencing menopause or post-menopause may also be more affected by heat due to changes in temperature regulation and increased hot flashes, which can add stress to the body.

Warning signs that the body is not handling the heat well can include dizziness, confusion, headache, nausea, muscle cramps, rapid heartbeat, extreme fatigue, or unusual sweating. Cold or clammy skin can also be a warning sign. If several symptoms occur or worsen, medical attention should be sought right away.

To protect blood pressure during hot weather, it is important to drink fluids regularly, even before feeling thirsty. Staying indoors during the hottest part of the day can also help. If time outdoors is necessary, wearing sunscreen, choosing clothing with UV protection, and staying in shaded areas can help reduce heat strain on the body. Wearing light clothing and resting in a cool environment can also help. Monitoring blood pressure more often during heat waves is a good idea for those with a history of high blood pressure.

Medications should be stored properly during hot weather. Heat can damage some medicines if they are kept in cars, near windows, or in humid bathrooms. Storing medications in a cool, dry place helps maintain their effectiveness. In summary, hot weather can affect blood pressure in several ways. Staying hydrated, keeping cool, watching for warning signs, and following healthcare guidance can help protect heart health during the warmer months.

Reference:

Gombert-Labedens, M., Vesterdorf, K., Fuller, A., Maloney, S. K., & Baker, F. C. (2025). Effects of menopause on temperature regulation. Temperature (Austin, Tex.), 12(2), 92–132. https://doi.org/10.1080/23328940.2025.2484499

Paulino, M. (2023). Effects of hot weather, humidity on blood pressure, heart. Mayo Clinic Health System. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/effects-of-high-temperatures-on-blood-pressure-heart