Winter increases heart attack risk

Nov 18 2012 - 10:51pm

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Winter is upon us, and with that comes the not so merry season of heart attacks. It's well-documented that more people have a heart attack in the winter months, but cold temperatures may only be one culprit.

A new study presented by two researchers at the recent American Heart Association conference found heart attacks do occur more in the winter, but not just in frigid temperatures. They also happen in warm climates.

According to Dr. Bryan Schwartz, of the University of New Mexico in Albuquerque, and Dr. Robert A. Kloner, of Good Samaritan Hospital in Los Angeles, deaths rise during December and January in seven regions of the country with very different climates.

"We know that heart-related deaths increase in the winter months ..." Schwartz said in a news release. "If it was solely because of cold temperatures, we would have seen more deaths in Pennsylvania and Massachusetts, and we didn't see that."

Both McKay-Dee Hospital and Davis Hospital and Medical Center treat more heart-attack patients in winter.

"Observational data has shown that the winter months are a prime time for a heart attack, but the reasons for this are unclear," said McKay-Dee cardiologist and electro physiologist Dr. Michael Eifling. "Cold temperatures may cause arteries to constrict, which increases demand on the heart and may set the stage for a heart attack."

Some data also suggests less daylight in winter may cause changes in the hormone cortisol, which can lower the threshold for a heart attack.

"It is known that heart attacks are more common in the morning hours when cortisol levels are higher, which may result in higher blood pressure and faster heart rate," Eifling said.

In addition, he said, many people are less active in the winter, which may increase the risk of heart attack. Some evidence points to lower levels of vitamin D in winter, although, Eifling said this hasn't been proven to

increase the risk of heart attack.

Dr. Travis Nelson, an emergency physician at Davis Hospital and Medical Center said stress -- either physical from shoveling snow or emotional with the holidays -- is another reason people might be at a greater risk during winter.

So does temperature play a role? A large study published in the national Registry of Myocardial Infarction found 53 percent more heart attacks in winter than summer and did point to cold temperature as one of the culprits.

"The body's natural response to cold is to protect vital organs ... by increasing blood flow to those organs, and limit heat loss by constricting blood flow to the outer edges of the body," Nelson said. "This is why the hands and feet are among the first to get cold when the body is trying to conserve heat."

Eifling and Nelson said a heart attack is caused when an artery supplying blood to the heart becomes blocked. Symptoms can include chest pressure or pain that may radiate to the jaw, shoulder or arm; shortness of breath; sweating; and cold, clammy skin. Women and people with diabetes may also experience pain in the upper back and abdomen, vomiting, dizziness and lightheadedness.

People who exercise outdoors should protect the body from heat loss. Wear a hat, dress in layers and stay dry. Ask your doctor if you have any risk factors, such as high blood pressure or diabetes. Be aware of the signs of a heart attack and call 911 if you experience any of the symptoms.

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