Stages of the Flu: And What To Do for Each

So you’ve got a cough that has your roommates, family members, or coworkers giving you the side-eye. And now you feel—oh no—just a little bit feverish. You start to frantically wonder: Is it the flu? And if so, how long will it last? Weeks? Hang on: Take deep breath and read this guide.

“Going viral” should be reserved for social media posts, but unfortunately, sometimes an IRL virus finds you. And yes, that pesky virus may well be the flu.

“Flu” is the cute little abbreviation for influenza viruses, which although can spread year round, typically ramp up in autumn and peak during winter months. When you’re spending lots of time in crowded rooms for the holidays, the season may just give you a gift you never wanted.

A rapid test from a pharmacy or clinic can tell you if you’ve got the flu, but you can also use other clues to determine if this particular virus has you feeling under the weather.

Flu symptoms tend to come in hot, meaning they show up abruptly and intensely. The intensity generally lasts for a few days, though symptoms can chill out a bit but linger for a couple of weeks, even after the acute stage has passed. The common cold, on the other hand, tends to take its time dragging you down with a slow onset of symptoms.

By the way, influenza is different from the “stomach flu,” which is a colloquial term for norovirus, a virus that causes gastroenteritis, leading to gastrointestinal (GI) symptoms. Picture the green nauseated-face emoji—or the poop one—and you’ll get the idea. Influenza can also cause GI symptoms, but the primary symptoms affect the respiratory tract—think coughing, a stuffy nose, and wanting to hide under the covers.

In this article, we cover flu symptoms day by day, stages of the flu, signs the flu is getting better, and more.

Flu timeline at a glance

Whether you’re wondering if the virus has come for you or you’re certain you’ve got it, you may want a timeline of the flu. Here’s a quick guide, with more info on each flu stage in the next section.

Stage-by-stage: What to expect and what to do

Now for all the details on these flu stages from incubation to recovery:

Incubation (days -1 to 0)

“When you first catch the flu,” says Adam Carewe, MD, a physician at General Medicine, “you usually don’t feel sick right away.” Instead, people are contagious beginning about 24 hours before their symptoms appear and up to five to seven days after onset.

You may not think about the flu until symptoms strike, but you can still be contagious in the day or so beforehand.

What to do: At this point, you likely don’t know you have the flu. But practicing good hygiene all the time can help mitigate the spread. Wash your hands after using the bathroom, after covering your mouth while coughing or sneezing, and before and after eating.

Sudden onset (day 0)

Day zero is the day you first experience symptoms, which tend to come on suddenly and intensely. “The flu often hits fast,” Dr. Carewe says. “It can feel like you were fine one minute and flattened the next.”

Common flu symptoms:

• Body aches
• Dry cough
• Fatigue
• Fever (perhaps with chills)
• Headache
• Loss of appetite
• Runny or stuffy nose
• Sore throat
• Vomiting or diarrhea

What to do: Stay home and avoid contact with others to prevent spreading the virus. Self-care is your best bet. Get plenty of rest, stay hydrated, and take any over-the-counter meds, such as fever reducers. Talk to your doctor right away if you are at risk for flu complications. People who may be at risk include those with chronic medical conditions, those 65 years or older, children under 5, and those who are pregnant. Seek immediate medical attention for the red flags listed in this article.

Peak illness (days 1-3)

Which day of the flu is the worst? Great question. Day number one is likely the winner.

Your symptoms will be most intense from days one to three. You are still highly contagious and need lots of rest and fluids.

What to do: Continue your self-care strategies and remain at home to avoid infecting others. If you experience any complications, talk to a doctor right away. If you’re wondering if you should get that workout in, the answer is probably not.

Stages of the flu

Turning the corner (days 4-6)

You should be starting to feel slightly better, but some symptoms can linger.

“Fever and aches may start to ease, but you’ll likely still feel drained and congested,” Dr. Carewe says. “Coughing and low energy can hang on.”

Even if you’re perking up a bit, you are still contagious until about day seven. However, young children and people with a weakened immune system may be contagious for longer.

What to do: Even if your symptoms are resolving, continue taking it easy and staying at home. If your appetite has been MIA, it may be returning now. Take advantage of it to introduce more nutrients. If you’re feeling up to it and you’re antsy to do some activity, gentle movement, such as a walk or easy stretching, should be fine and may even help, but don’t overdo it.

Recovery (days 7 to 10+)

“By now, most people are on the mend,” Dr. Carewe says. “The fever is gone, and your energy slowly returns. The cough and fatigue can stick around for another week or two, but you should notice steady improvement.”

What to do: Once you’re beyond day seven and feeling better, you’re likely no longer contagious. You can return to work if you feel up to it, but continue to get lots of rest and fluids and take advantage of your improved appetite and nourish your body with healthy foods. If you’re returning to physical activity, start out slow and easy and gradually return to your regular routine as symptoms fully resolve. Now is not the time for a CrossFit workout or running a marathon.

Signs the flu is getting better

After the peak illness phase, you should notice some signs that you’re feeling better. That doesn’t mean you’ll suddenly bounce back to your pre-flu era right away though.

“You’re likely improving when your fever stays down below 100 degrees Fahrenheit without medication, your body aches lessen, you start to feel hungry again, and your energy begins to come back,” Dr. Carewe says. “The cough may still linger, but it shouldn’t feel as rough or deep.”

You’re generally improving if you notice the following:

• You’re fever free for 24 hours without fever reducers.
• You’re feeling your appetite return, though you may not be in the mood for all your usual favorites quite yet.
• Your energy is on the upswing, but you may not feel like going full throttle, nor should you.
• Your symptoms are easing or even resolving. Keep in mind that a cough, a runny or stuffy nose, a sore or scratchy throat, and fatigue can linger, but they shouldn’t be at their worst any longer.

When to seek medical care (red flags)

If you encounter any of these severe symptoms from the flu or another illness, you should consult a medical provider right away, as you may be experiencing complications from the flu:

• Difficulty breathing or shortness of breath
• Chest pain, tightness, or pressure
• Worsening of an underlying condition, such as asthma, chronic obstructive pulmonary disease (COPD), diabetes, cardiovascular disease, etc.
• High fever, greater than 104 degrees Fahrenheit
• Seizures
• Persistent vomiting or diarrhea
• Not urinating
• Confusion or severe mood changes
• Severe body or muscle pain
• Symptoms that get worse beyond day three or four or that improve for a bit and then get worse
• Blueish or gray skin
• Sudden dizziness (or fainting)
• In children: not waking up or interacting with you or not wanting to be held
• In children under 12 weeks: any fever

Some people should talk to a clinician at the first signs of the flu, including:

• Those with underlying conditions (especially heart and lung diseases, diabetes, and autoimmune conditions)
• People who are immunocompromised from a condition or medication
• Pregnant people
• People caring for a child under age 5

Testing and treatment overview

At most pharmacies, you can buy a rapid flu test and administer it yourself in the comfort of your own home. However, you can also get tested at your local clinic, including walk-in options or urgent care. Clinicians may also diagnose you based on your symptoms.

However, ever since the COVID-19 pandemic, the use of rapid tests has become more common to help people and providers know exactly what they have. By the way, you can have both COVID and the flu at same time. How’s that for going viral, eh?

Once you know you’ve bought yourself a course of the flu, you may be wondering about the best treatments. Typically, the flu resolves on its own with self-care. (Read on for tips.)

Antibiotics are useless against the flu, which is a virus, rather than a bacterial infection. “They’re only used if you develop a bacterial complication, such as pneumonia or a sinus infection, that occurs after or alongside the flu,” Dr. Carewe says. “That’s why it’s important to reach out if your symptoms improve and then take a turn for the worse. That pattern often means a bacterial infection on top of the flu.”

Some other medications may be beneficial, depending on your circumstances.

Antivirals

“If you’re at higher risk for flu complications or you catch it early, ask about prescription antiviral medication,” Dr. Carewe says. “These work best when started within the first 48 hours of symptoms.” Definitely talk to a provider if you have underlying conditions.

Antivirals include oseltamivir (Tamiflu), zanamivir (Relenza), peramivir (Rapivab), and baloxavir marboxil (Xofluza). They may shorten your illness by a couple days, lessen symptom severity, reduce risk for complications, including hospitalization or death in severe cases).

Supportive over-the-counter options

These can be obtained over-the-counter at your local pharmacy and other stores.

Antipyretics

That’s a fancy word for fever reducers, which as a bonus, may also help relieve body aches or a headache. These meds include nonsteroidal anti-inflammatory drugs (NSAIDS, such as ibuprofen, aspirin, etc.) and acetaminophen. When in doubt, consult a clinician about which antipyretics are safe for you or your child.

Do not give children or teens aspirin, which can cause Reye syndrome, which can be fatal. Some people should also avoid NSAIDs, including those who are pregnant or breastfeeding and who have an asthmatic or allergic reaction to these meds, gastrointestinal conditions (such as bleeding, reflux, or inflammatory bowel disease, aka IBD), kidney or liver problems, or cardiovascular disease. You should avoid acetaminophen if you have kidney liver disease, engage in heavy alcohol consumption, or have had a previous allergic reaction to the medication.

Symptom relievers

Some over-the-counter options can also help ease your other symptoms:

• Saline nasal rinses to ease nasal congestion or a runny nose
• Decongestants, such as pseudoephedrine, to open a stuffy nose (Avoid if you have glaucoma, cardiovascular disease, an enlarged prostate, or are pregnant or breastfeeding, and do not give to children under 6.)
• Throat sprays, which come in various preparations, to either numb or soothe a sore throat

Self-care toolkit

Symptom relief—and potentially a speedier recovery—often comes down to good self-care at home. Try these options:

Stay hydrated

Consuming plenty of water is crucial to support your immune system, thin mucus secretions, counteract fever, and help filter waste. Aim for consuming 125 ounces (about 15.5 cups) of water if you’re male and 91 ounces (about 11.5) if you are female. But during a bout of the flu, you may need even more.

In addition to water, you can sip broth, herbal tea (add honey to soothe your throat), and other beverages to amp up your fluid intake. If you experience diarrhea or vomiting, you may also need some electrolytes to support your hydration.

Get plenty of rest and sleep

Rest allows your body to put its available energy and resources toward fighting the flu. Park yourself on the couch or in bed, especially when your symptoms are at their peak.

Get plenty of sleep, too. Sleep helps your immune system battle the virus. Aim for at least eight hours of slumber per night when sick, but you may find yourself snoozing more than usual, which is a good thing. Now is certainly not the time to short-change yourself on sleep. Naps throughout the day are encouraged.

Nourish your body with gentle foods

An old wives’ tale suggests that you “feed a cold, starve a fever.” But this is a myth. Your body needs nutrients to wage war on viral infections.

You may have a reduced appetite when the flu first comes on and as you recover. But you still need to take in calories. Again, broths, soups, smoothies, and other easy-to-digest options can help.

Avoid smoking or alcohol

Dr. Carewe recommends abstaining from smoking or vaping and from drinking alcohol. All can worsen the flu and impair your immune system’s ability to fight it.

Common complications

Although the flu tends to resolve on its own in generally healthy people, sometimes complications can ensue. If you notice any of the red flags listed earlier in the article, seek medical care right away.

• Acute respiratory distress syndrome (ARDS): A severe lung injury
• Bronchiolitis: A viral infection of the lower respiratory tract (usually in children)
• Bronchitis: Inflammation of the bronchi lining caused by bacteria or a virus
• Encephalitis: Inflammation of brain tissue caused by a virus
• Encephalopathy: Brain dysfunction or disease
• Guillain-Barré syndrome: Autoimmune destruction of nerves caused by infection
• Hepatitis: Liver inflammation
• Meningitis: Inflammation of the vertebral canal, skull, and spinal cord
• Myocarditis: Inflammation of the heart muscle
• Myocardial infarction: Heart attack
• Otitis media: Inner-ear infection
• Pancreatitis: Inflammation of the pancreas
• Pericarditis: Inflammation of the sac surrounding the heart
• Pneumonia: A bacterial or viral lung infection
• Sinusitis: A bacterial or viral sinus infection

Common flu symptoms

Prevention

“The best protection is a yearly flu shot,” Dr. Carewe says. “Even if it doesn’t prevent infection completely, it greatly reduces your risk of serious illness or hospitalization.” People who are over 65 years old, pregnant individuals, and those with chronic conditions are prioritized for high-dose flu vaccines or those that are adjuvanted (have an ingredient added to improve effectiveness).

He also recommends practicing good hygiene year-round, with these tips:

• Wash your hands often with soap and water.
• Cover coughs and sneezes with your elbow or a tissue.
• Avoid close contact with people who are sick.
• Disinfect surfaces like phones, keyboards, and door handles.

Key takeaways

• Symptoms of the flu tend to come on fast and intensely, and they typically lessen within a week, though symptoms may linger for up to two weeks.
• Antibiotics do not help the flu, but antiviral medications might ease symptoms, prevent complications, and speed recovery.
• Never hesitate to talk to a provider for an antiviral medication, especially if you have an underlying condition, and seek help if you develop any red-flag symptoms or complications.
• General Medicine can help you from the comfort of your home.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Swapna Ghanta, MD, and Ecler Ercole Jaqua, MD

FAQ

What are the 5 stages of the flu?

The five stages of the flu are (1) incubation and exposure (which can occur in the days before you develop symptoms, (2) abrupt onset (the day you first experience symptoms), (3) peak illness (the next three days when your symptoms are likely at their worst), (4) turning the corner (days four through six, when you’re symptoms are easing), and (5) recovery (days seven and beyond, when you’re drastically improved but may have lingering symptoms).

What are signs the flu is going away?

Most people with the flu will start to feel somewhat better by the fourth day of their symptoms, which should be easing. However, they may still linger but with less intensity as time progresses. You might not feel completely back to normal for a full two weeks from symptom onset.

What are the end stages of flu?

In the end stages of the flu, about day eight of your symptoms, you will likely begin to feel much better, though you may not feel like you’re 100% back to normal for up to two weeks from the time you first noticed symptoms.

What are the warning signs of severe flu?

The warning signs of severe flu include difficulty breathing or shortness of breath, chest pain or pressure, high fever, worsening underlying conditions, persistent vomiting or diarrhea, severe body aches, confusion, and more. See a doctor right away if you experience these issues.