How Long Does the Flu Last? Why Your Body Is Still Aching & Medical Next Steps

If you're asking how long does the flu last, you're not alone. Influenza (the flu) can hit hard and fast, leaving you with fever, chills, body aches, fatigue, cough, and headaches. Even after the fever breaks, you may still feel drained or achy for days.

Here's what to realistically expect, why your body may still hurt, and when it's time to take the next medical step.

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How Long Does the Flu Last?

For most healthy adults, the flu typically lasts 5 to 7 days. However, some symptoms can linger longer.

Typical Flu Timeline

Days 1–3: Sudden Onset

• High fever (100–104°F)
• Chills and sweats
• Severe body aches
• Headache
• Extreme fatigue
• Dry cough
• Sore throat

Flu symptoms usually come on quickly — often within hours.

Days 4–7: Peak and Early Recovery

• Fever begins to improve
• Body aches lessen
• Cough may continue
• Fatigue remains

Most people start feeling better by the end of the first week.

Week 2 and Beyond: Lingering Symptoms

• Ongoing fatigue
• Mild cough
• Weakness
• Reduced stamina

It's common to feel "not quite yourself" for 1–2 weeks, especially if the flu hit you hard.

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Why Is Your Body Still Aching?

If your fever is gone but your body still aches, that can feel frustrating. Here's why it happens.

1. Your Immune System Is Still Working

When you get the flu, your immune system releases chemicals called cytokines. These help fight the virus but also cause:

• Muscle soreness
• Joint aches
• Headache
• Fatigue

Even after the virus is mostly cleared, your body may still be cleaning up inflammation.

2. Dehydration

Fever, sweating, and poor appetite can lead to dehydration. Low fluid levels can cause:

• Muscle cramps
• Headaches
• Weakness
• Dizziness

Drinking water, electrolyte drinks, and clear broths can help.

3. Muscle Breakdown from Inactivity

When you're stuck in bed for days, muscles can stiffen and weaken. Even small movements may feel uncomfortable once you start being active again.

4. Post-Viral Fatigue

Some people experience lingering exhaustion after viral infections. This can last:

• Several days
• Occasionally a few weeks

This doesn't mean something is wrong — it often just means your body needs more time to recover.

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When Should You Feel Concerned?

While most flu cases resolve on their own, complications can happen. It's important not to ignore warning signs.

Seek medical care immediately if you have:

• Trouble breathing or shortness of breath
• Chest pain or pressure
• Confusion or difficulty staying awake
• Severe or persistent vomiting
• Blue lips or face
• Symptoms that improve but then suddenly worsen

These could signal complications like pneumonia, dehydration, or worsening infection.

Higher-Risk Groups

Some people are more likely to develop serious complications:

• Adults over 65
• Young children
• Pregnant individuals
• People with asthma, diabetes, heart disease, or weakened immune systems

If you're in a higher-risk group and wondering how long does the flu last, it's especially important to stay in touch with a healthcare professional.

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How Long Is the Flu Contagious?

Most people are contagious:

• 1 day before symptoms start
• 5–7 days after becoming sick

Children and people with weakened immune systems may spread the virus longer.

You're generally less contagious once:

• Your fever is gone for 24 hours (without fever-reducing medicine)
• Symptoms are clearly improving

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What Can You Do to Recover Faster?

There's no instant cure for the flu, but you can support your recovery.

1. Rest — More Than You Think You Need

Your body heals during rest. Pushing yourself too soon can prolong recovery.

2. Hydrate Aggressively

Aim for:

• Water
• Herbal teas
• Clear soups
• Electrolyte solutions

Avoid excess alcohol or caffeine.

3. Use Over-the-Counter Medications Wisely

Medications can ease symptoms but won't shorten illness duration:

• Acetaminophen or ibuprofen for fever and aches
• Cough suppressants if needed
• Saline sprays for congestion

Always follow dosing instructions.

4. Antiviral Medications

Prescription antivirals (like oseltamivir) may:

• Shorten illness by about 1 day
• Reduce complications
• Be most effective if started within 48 hours of symptom onset

These are especially recommended for high-risk individuals.

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Why Do Some People Feel Sick Longer?

If you're still feeling poorly after 7–10 days, possible reasons include:

• Secondary bacterial infection (like sinusitis or pneumonia)
• Dehydration
• Not enough rest
• Underlying medical conditions
• Another virus mimicking the flu

If symptoms are not gradually improving, it's reasonable to check in with a healthcare provider.

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Could It Be Something Other Than the Flu?

COVID-19, RSV, common colds, and other respiratory viruses can cause similar symptoms. Testing may be helpful in some cases, especially during peak respiratory virus season.

If you're experiencing confusing symptoms and want clarity on whether it could be the flu, Ubie's free AI-powered Influenza (Flu) symptom checker can help you quickly understand what might be happening and guide your next steps toward feeling better.

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When to Speak to a Doctor

Even if you know how long the flu lasts, every person is different. Speak to a doctor if:

• You are not improving after 7–10 days
• Your fever lasts more than 3–4 days
• You develop worsening cough with thick mucus
• You have underlying medical conditions
• You feel something "just isn't right"

And always seek urgent care for any life-threatening or severe symptoms.

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The Bottom Line: How Long Does the Flu Last?

To summarize:

• Most people recover in 5–7 days
• Fatigue and cough may last 1–2 weeks
• Body aches can linger due to inflammation and immune response
• Complications are uncommon but serious when they occur
• High-risk individuals should seek early medical guidance

The flu is tough, but in most cases, your body clears it on its own with rest, hydration, and time.

If you're unsure about your symptoms, consider using a free AI-powered symptom checker for Influenza (Flu) to get personalized insights, and speak to a doctor about anything that could be serious or life threatening. Trust your instincts — getting medical advice when needed is always the right move.