People with heart failure are at higher risk of serious flu complications, and influenza can worsen their condition. If flu symptoms begin, contact a healthcare professional promptly; prescription antiviral treatment may be recommended and works best when started early. Watch for worsening breathlessness, swelling, or sudden weight gain. Seek emergency care for difficulty breathing or persistent chest pain. Yearly flu vaccination helps lower the risk of flu and its complications.
Why Can the Flu Be More Serious for People With Heart Failure?
Heart failure is a condition in which the heart cannot pump blood as well as the body needs. Influenza, commonly called the flu, is a contagious respiratory infection that can cause illness ranging from mild to serious. When someone has heart failure, a flu infection may worsen their existing condition and increase the risk of complications.
The Centers for Disease Control and Prevention (CDC) identifies heart failure as a type of heart disease associated with a higher risk of serious flu complications. Flu can also lead to problems such as pneumonia and inflammation of the heart muscle. These complications can require urgent medical care, particularly when someone already has a chronic heart condition.
Another concern is that flu symptoms and worsening heart failure can occur at the same time. For example, a cough or unusual tiredness may occur with a respiratory infection, but these symptoms can also be associated with heart failure. Recognizing changes from your usual health and contacting your healthcare team promptly can help you get the right assessment and treatment.
Which Flu Symptoms Should You Watch For?
According to the CDC's guidance on flu symptoms, influenza often begins suddenly. Common symptoms include fever, chills, cough, sore throat, a runny or stuffy nose, muscle aches, headaches, and tiredness. Some people also experience vomiting or diarrhea. Not everyone with flu develops a fever, so the absence of fever does not rule it out.
For someone living with heart failure, it is also important to notice symptoms that are new, more frequent, or worse than usual. The U.S. National Library of Medicine's MedlinePlus guidance on heart failure describes several symptoms that can occur when the condition is worsening, including:
- Shortness of breath during everyday activities or while resting.
- Greater difficulty breathing when lying flat or waking at night because of breathlessness.
- New or increased swelling in the feet, ankles, legs, or abdomen.
- Sudden weight gain, which may indicate a buildup of fluid.
- A worsening cough, unusual weakness, or increased fatigue.
- A fast or irregular heartbeat, particularly when accompanied by other symptoms.
Some of these symptoms overlap with flu symptoms, so a single symptom cannot reliably distinguish an infection from worsening heart failure. Pay attention to how you feel compared with your usual condition. For example, a cough accompanied by noticeably worse breathing or new leg swelling deserves prompt medical attention. A healthcare professional can assess your symptoms, medical history, and changes over time to determine the likely cause.
What Should You Do If You Have Heart Failure and Develop Flu Symptoms?
Contact your healthcare professional as soon as flu symptoms begin, even if they initially seem manageable. The CDC recommends prompt medical contact for people with heart disease who develop flu symptoms. Make sure the clinician knows that you have heart failure and describes any changes in your breathing, swelling, weight, or usual ability to perform daily activities.
Early medical contact matters because prescription antiviral medicines may be appropriate for people with heart failure who have confirmed or suspected influenza. These medicines act against influenza viruses and are different from antibiotics, which treat bacterial infections. Your clinician can decide whether testing or antiviral treatment is appropriate based on your symptoms, health history, and current condition.
The CDC's guidance on flu antiviral treatment states that these medicines generally work best when started within one to two days after symptoms begin. However, treatment may still help when started later, especially for people at increased risk of serious complications or those who are hospitalized. Do not wait for symptoms to become severe before contacting your healthcare team.
How Can You Manage Heart Failure While Recovering From the Flu?
Continue following your prescribed heart failure treatment plan unless your healthcare professional tells you to make a change. The CDC specifically advises people with heart disease not to stop their regular medicines without consulting their healthcare provider, including when they develop flu or another respiratory infection. If you are having trouble taking your medicines because of vomiting, difficulty swallowing, or another illness-related problem, contact your healthcare team for instructions rather than changing your doses on your own.
Continue following your usual guidance on salt and fluid intake. Some people with heart failure are advised to limit the amount of fluid they drink, so drinking substantially more than usual when ill may not be appropriate for everyone. Fever, vomiting, or diarrhea can also complicate the management of an existing health condition. Ask your clinician how to manage your individual fluid plan if you are struggling to eat or drink normally or are losing fluids.
Keep track of your breathing, swelling, and weight if these are part of your usual heart failure care plan. A noticeable weight increase over a few days or worsening swelling may reflect a buildup of fluid rather than simply a change in appetite or activity during the illness. Report these changes promptly. Your healthcare team may need to review your condition and advise whether your treatment plan requires adjustment.
Be cautious with over-the-counter cold and flu products. Medicines that are suitable for one person may not be appropriate for someone with heart failure. MedlinePlus notes that certain medicines, including ibuprofen and naproxen, can make heart failure worse. Check with a healthcare professional or pharmacist before taking a new cold remedy, pain reliever, supplement, or herbal product. This is particularly important if you already take several prescription medicines.
Rest while you recover and avoid pushing yourself through activities that leave you unusually breathless or weak. Follow your clinician's advice about returning to your usual activity level. If your symptoms worsen, your breathing changes, or you develop new swelling or sudden weight gain, seek medical advice rather than assuming these changes are a normal part of recovering from flu.
When Does the Flu Require Emergency Care?
Flu can sometimes lead to complications that require immediate treatment. Seek emergency medical care if you experience any of the following:
- Difficulty breathing or severe shortness of breath.
- Persistent pain or pressure in the chest or abdomen.
- New confusion, persistent dizziness, or difficulty staying awake.
- Fainting or a rapid, irregular heartbeat accompanied by concerning symptoms.
- Little or no urination, particularly when accompanied by other signs of serious illness.
- Symptoms that improve and then return or become substantially worse.
The CDC's list of emergency warning signs of flu complications includes breathing difficulties, persistent chest or abdominal pain, confusion, and worsening of chronic medical conditions. With heart failure, a marked change in breathing is particularly important. Do not delay emergency care while waiting for a fever to develop or for other symptoms to appear. Contact your local emergency service if a potentially life-threatening symptom occurs.
How Can You Reduce Your Risk of Flu With Heart Failure?
Annual flu vaccination is an important way to reduce the risk of influenza and its potentially serious complications. The CDC recommends yearly flu vaccination for everyone aged six months and older, with particular importance for people at increased risk of severe illness, including those with heart disease. Your healthcare professional can help you choose an appropriate vaccine based on your age, medical history, and local recommendations.
Vaccination does not prevent every flu infection, but it can reduce the risk of illness and may lessen its severity. If you have questions about vaccine safety or which formulation is suitable for you, discuss them with your healthcare professional before the flu season begins.
Everyday precautions also help reduce exposure to respiratory viruses. Wash your hands regularly, cover coughs and sneezes, improve indoor ventilation when possible, and avoid close contact with people who are sick. If you develop flu symptoms, limit contact with others while ill and follow current public health guidance on preventing the spread of infection.
It can also help to plan ahead. Keep an up-to-date list of your medicines and your healthcare team's contact details, and ask whether you should maintain an extra supply of essential prescriptions. Knowing whom to call if symptoms begin can make it easier to obtain prompt advice and avoid unnecessary delays in care.
Living with heart failure does not mean that every flu infection will cause a serious complication. However, taking symptoms seriously, seeking early medical advice, following your prescribed care plan, and staying up to date with recommended vaccination can help reduce avoidable risks.