Why do flu symptoms last for such a long time?

December 13, 2023
Avatar for Jyoti KinghornJyoti Kinghorn
Flu symptoms can last a long time

Getting the flu takes a toll on your body. A runny nose, high fever, headaches and body aches make the first five days of the flu infection very painful. Even if you are healthy and do not develop any complications, it can still take a long time to truly feel better again and regain your former levels of energy.

Flu symptoms can last a long time

Timeline of flu symptoms and recovery

While everyone is different, most people who get sick with the flu (without complications) will observe a similar course of recovery.

Day 0. This is the day before you will start showing symptoms. You are already infected, and contagious.

Day 1. This is your first day of symptoms. Unlike the common cold which tends to develop gradually, flu symptoms can all develop rapidly within a few hours. Symptoms include a runny or stuffy nose, weakness, fever, feverish chills, headaches, body aches, muscle weakness, and a sore throat.

Days 2-4. This is when your symptoms are at their worst.

Days 5-7. Symptoms typically start getting better on this day for most people. If you feel better, you may be able to go out. According to the CDC, most people stay infectious up to 5-7 days after symptoms develop.

Note: If you do not feel an improvement in your symptoms 5 days after your symptoms first developed, you should see a healthcare provider. Flu can result in more serious complications such as pneumonia.

1-2 weeks. While most of your symptoms are better, you may still feel muscle weakness and fatigue.

2-8 weeks. Some people may have a lingering cough and exhaustion. All such symptoms should also clear out within 8 weeks.

Flu symptoms can last a long time

Why some flu symptoms last longer

A lingering cough and exhaustion are two of the most commonly seen symptoms that can last for weeks or even a few months after the flu.


Lingering cough

A battle with the flu can leave your respiratory system irritated and with some inflammation. This can take a few weeks to heal, and you may observe a cough meanwhile.
However, the cough should be getting better every day. If you feel that after the first week your cough hasn’t recovered significantly, it could be a sign of an infection such as bronchitis or viral pneumonia. If you hear wheezing, it may be a sign of bronchiolitis. To avoid getting worse, it is important to see your medical provider.



Flu and fatigue go hand-in-hand, and most people who get the flu also feel extreme exhaustion. Even as you get better, you could feel fatigued for a few weeks. The fatigue is characterized by feeling sluggish, muscle pain or mild joint pain.
When we get the flu, our immune system releases white blood cells and directs them to fight the viral infection. This can result in inflammation which is one of the reasons responsible for the aches and pains associated with the flu. As the body heals, the inflammation gets better and the aches and pains subside, though it can take a few weeks.
Extreme exhaustion from the flu can feel debilitating. But just like the cough at the end of the flu, the feeling of fatigue should be manageable and should not discomfort you too much. If you feel that the feeling of fatigue is not improving, you should seek the advice of your healthcare provider to ensure there is nothing else going on that could be causing these symptoms.


Secondary infections


When you have the flu, your immune system is going into overdrive to fight the virus off. You are susceptible at this time to getting other diseases on top of the flu, such as a cold, COVID-19, or RSV infection- all of which circulate during the winter months. If you catch another infection while having symptoms from the flu, it can feel like the sickness has been ongoing for too long. Since symptoms from these infections overlap, it may be impossible to know without testing which ones you have at which point. Fast tests are now available to help you test which infections you currently have.


Flu shot


A flu shot can help people not get the flu in the first place, or have a reduced reaction to it after getting it. You can get a vaccine for flu and COVID-19 at the same appointment. If you are over 60 years of age, your doctor may advise you to get RSV vaccine at the same time. While there can be no vaccine for the common cold (it is a group for hundreds of viruses), the available vaccines can help you avoid the worst of these fall weather maladies.

The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.

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