Got the flu recently? Here's why you are at increased risk of heart attack and stroke after recovery

Most of us get the flu - while some get it once every couple of years, others might get it every year. While recovering from flu is easy with rest, and plenty of hydration, and usually does not require hospitalization, emerging research now says that people who get laboratory-confirmed flu, become four times more likely to have heart attacks, and five times more likely to have strokes during the month after their illness. Let's learn more..

What the big review found

A team of researchers analysed 155 high-quality studies that examined viral infections and their effects on heart and brain health over almost three decades. The researchers discovered a distinct pattern when they combined their data, which showed that heart attack and stroke risk increased dramatically, following influenza infections during the initial month after illness. Overall, people were about four times more likely to have a heart attack and five times more likely to have a stroke in the 30 days after confirmed flu, than during periods when they did not have the infection.




The flu virus creates conditions which lead to heart attacks in patients

Flu is not 'just a cold'; it creates a complete body infection which produces intense inflammatory reactions. This inflammatory response can make fatty deposits (plaques) in the arteries more unstable, so they are more likely to crack or rupture, which can suddenly block blood flow to the heart, and cause a heart attack. The body responds to infection by raising heart rate, boosting oxygen requirements and stress hormone production, which intensifies the pressure on already constricted arteries, that affect older people and those who have diabetes, high cholesterol or high blood pressure.

Why stroke risk also goes up

The same processes that affect the heart can affect the brain. Infections like influenza can make the blood more “sticky,” increase clotting factors and inflame the inner lining of blood vessels, which raises the chance that a clot will form and travel to the brain, causing an ischaemic stroke. Blood pressure levels in patients with severe illnesses tend to change unpredictably, while their body loses fluids and they stay in bed, which increases their chances of getting a stroke, especially when they have atrial fibrillation, or other vascular diseases.

When is the risk highest

The increased risk is strongest shortly after infection, and then slowly falls over time. Some studies have shown that the chance of a heart attack can be many times higher in the first week, after a confirmed flu diagnosis, then gradually decreases over the following weeks. The research study which evaluated the evidence base for the "four times" and "five times" statistics, examined the first month of the study period, because this time frame showed elevated heart attack and stroke risks which exceeded typical levels before the risks returned to normal levels.

Who is most at risk

The threat exists for all people but particular social groups experience elevated vulnerability. These include:

People with existing heart disease, such as coronary artery disease, heart failure or previous heart attack.

Those who have had either a stroke or a TIA (mini‑stroke) before.

The population at highest risk includes people aged 65 and older, together with individuals who have diabetes, high blood pressure, high cholesterol, obesity or chronic kidney disease.

The hospital data showed that heart disease affected 47% of adult flu patients and 12% of these patients developed severe heart complications, which included acute heart failure and ischaemic heart disease.

Role of vaccination and treatment

The good news is that vaccination and prompt treatment can lower these risks. Research studies indicate that annual flu vaccination leads to reduced major heart events, according to multiple investigations, which demonstrate that vaccinated people experience a 33% lower risk of heart attacks and strokes, than unvaccinated people. People who have heart disease or those who have experienced a stroke, need to seek immediate medical evaluation from a doctor, because antiviral treatment for flu symptoms at the starting of illness, helps shorten both the duration of illness and prevents potential complications.

What to watch for after the flu

If someone has had the flu in the last month, they should be alert to warning signs of heart attack and stroke. The following medical emergencies require immediate medical assistance:

• Chest pain, pressure and sudden shortness of breath and pain, that moves from the chest to the arm or jaw
• Sudden weakness in one body part, speech difficulties, vision loss and severe headaches that appear suddenly.
• Those who have had heart disease need to maintain proper hydration while following their doctor's medication schedule, and should wait until their flu recovery is complete, before performing strenuous activities.

Disclaimer: This article is informational only and not a substitute for medical advice