Harvard Health Letters
January 28, 2010
As of early October 2009, much of the focus has been on swine flu (more formally called H1N1 flu). That's understandable. H1N1 is new, and no one knows how much damage it will cause. But the "regular" flu isn't something to sneeze at. Seasonal flu kills about 36,000 people each year in the United States, hospitalizes more than 200,000, and costs us more than $10 billion in direct medical expenses and lost productivity.
Seasonal flu and H1N1 flu are different in some ways and similar in others. One of the similarities is that both may be hard on the heart. Getting vaccinated against seasonal flu and swine flu is good insurance for your health and heart.
FLU CAN HARM THE HEART
Infections of any kind can affect the heart and circulatory system. Influenza (the flu) is no different. It can make breathing difficult, boost blood pressure, make the heart beat faster, and rev up inflammation. All of these force the heart to work harder. A healthy heart usually weathers these changes without a problem; a damaged or weakened heart may not. Infection can also cause a vulnerable, cholesterol-filled plaque inside a coronary artery to break apart. The blood clot that forms to seal the break can block the artery, causing a heart attack or sudden death.
Over the years, a number of studies have linked flu with cardiovascular problems. An analysis of 39 studies showed consistent connections between influenza and heart attack or cardiovascular-related death (Lancet Infectious Diseases, October 2009).
There's no reason to believe that the H1N1 flu will be any less hazardous to the heart, and some experts worry it could be even more devastating. At the 2009 European Society of Cardiology meeting in Barcelona, top cardiologists warned that swine flu and heart disease could be a deadly mix. Although most people with heart disease are over age 60 -- a group that seems to be less susceptible to the H1N1 virus -- there could be major complications for those who do catch it.
One reason is that H1N1 flu tends to infect the lungs rather than the upper airway, as is more common with seasonal flu. The accumulation of fluid coupled with flu-related breathing problems could severely stress individuals with heart failure, many of whom already have fluid buildup in the lungs.
SEASONAL OR SWINE?
If you come down with flulike symptoms - a sore throat, fever or chills, headache or muscle aches, extreme tiredness, nausea, vomiting, or diarrhea -- there's no simple way to tell if you have seasonal flu or swine (H1N1) flu. A laboratory test for the H1N1 virus is the only sure way to tell the difference.
Most otherwise healthy folks recover fully from seasonal flu or H1N1 with rest, staying hydrated, and some ibuprofen or acetaminophen to help with pain or fever. Some people, though, will need antiviral medications or hospitalization. Seek medical care if you or the person you are caring for:
If you are concerned about your illness, call your health care provider for advice. Use the emergency room as a last resort; if you go there and don't have the flu, it's a great place to catch it from those who do.
PREVENTION IS BEST
The two V's - vaccine and vigilance - are your best tools for avoiding the flu. Because seasonal flu contains a different mix of viruses each year, you need to get vaccinated every year. But this vaccine doesn't include anything to fight H1N1, which is why the U.S. Centers for Disease Control and Prevention worked feverishly to create a new vaccine for it.
For seasonal flu, older people and those with heart disease, lung disease, diabetes, or other chronic conditions are at the top of the list for getting the vaccine. That's not the case for H1N1. People born before 1957 are less likely to be stricken with the virus than younger people. That doesn't mean you shouldn't get the swine flu shot if you're older than that - you should - just that you won't be first in line.
Vigilance is even more important. You don't need to hibernate at home until summer. Following these tips can help keep you flu-free:
Stay home for at least 24 hours after your fever is gone except for getting medical care or other necessities. While you're sick, limit contact with others as much as possible to keep from infecting them.
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