Effects of hot weather, humidity on blood pressure, heart

Weather can play a role in triggering certain health problems. High temperatures and high humidity are two factors that can cause serious health consequences for people with high blood pressure and heart disease.

Blood pressure can be affected in summer weather because of the body's attempts to radiate heat. High temperatures and high humidity can cause more blood flow to the skin. This causes the heart to beat faster while circulating twice as much blood per minute than on a normal day.

The greatest risks are when the temperature is above 70 degrees F and the humidity is more than 70%. The higher the humidity, the more moisture in the air.

Some people are at higher risk of being affected by humidity, including people over 50; those who are overweight; or those who have heart, lung or kidney conditions.

Heat and sweating also can lower the amount of fluid in the body, which can reduce blood volume and lead to dehydration. This can interfere with the body's ability to cool off and may create strain on the heart.

Other risk factors include:

• Adults with heart, lung and kidney problems
• Seniors who follow a low-salt or low-sodium diet
• People who have a circulatory disease or problems with circulation
• Adults who take diuretics, sedatives and blood pressure medication

People who have a history of high blood pressure should monitor their blood pressure during heat waves. Also, drink plenty of fluids to stay hydrated, avoid midday heat, eat a healthy diet, apply sunscreen if outdoors and wear a hat. In most cases, when in doubt, stay home.

Warning signs that your body isn't keeping up with the heat include:

• Confusion
• Dizziness
• Disorientation
• Rapid pulse
• Headache
• Fatigue
• Nausea
• Excessive sweating or an inability to sweat
• Cold, clammy skin
• Muscle cramps or spasms
• Swelling in extremities

If you or a loved one are exhibiting more than one or two of these symptoms, it's important to seek medical intervention immediately.

Heather Mpemwangi, is a nurse practitioner in Cardiology in La Crosse, Wisconsin.