1. Sudden or excessive fatigue
Shorter days and reduced sunlight can make you feel tired. There’s a difference between being tired and experiencing extreme fatigue.

Sudden, excessive fatigue is one of the earliest symptoms of the flu. It may appear before other symptoms. Fatigue is also a symptom of the common cold, but it’s usually more severe with the flu.

Extreme weakness and tiredness may interfere with your normal activities. It’s important that you limit activities and allow your body to rest. Take a few days off from work or school and stay in bed. Rest can strengthen your immune system and help you fight the virus.

2. Body aches and chills
Body aches and chills are also common flu symptoms.

If you’re coming down with the flu virus, you may mistakenly blame body aches on something else, such as a recent workout. Body aches can manifest anywhere in the body, especially in the head, back, and legs.

Chills may also accompany body aches. The flu may cause chills even before a fever develops.

Wrapping yourself in a warm blanket can increase your body temperature and possibly reduce chills. If you have body aches, you can take over-the-counter pain relieving medication, such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin).

3. Cough
A persistent dry cough can indicate an early illness. It may be a warning sign of the flu. The flu virus can also cause a cough with wheezing and chest tightness. You might cough up phlegm or mucus. However, a productive cough is rare in flu’s early stages.

If you have respiratory problems, such as asthma or emphysema, you may need to call your doctor to prevent further complications. Also, contact your doctor if you notice foul smelling, colored phlegm. Flu complications can include bronchitis and pneumonia.

Take cough drops or cough medicine to calm your cough. Keeping yourself and your throat hydrated with lots of water and caffeine-free teas can also help. Always cover your cough and wash your hands to prevent spreading the infection.

4. Sore throat
Flu-related coughing can quickly lead to a sore throat. Some viruses, including influenza, can actually cause a swollen throat without a cough.

In the earliest stages of the flu, your throat may feel scratchy and irritated. You may also feel a strange sensation when you swallow food or drinks. If you have a sore throat, it’ll likely get worse as the viral infection progresses.

Stock up on caffeine-free tea, chicken noodle soup, and water. You can also gargle with 8 ounces of warm water, 1 teaspoon of salt, and 1/2 teaspoon of baking soda.

5. Fever
A fever is a sign that your body is fighting off an infection. Flu-related fevers are typically over 100.4˚F (38˚C).

A fever is a common symptom in early stages of the flu, but not everyone with the flu will have a fever. Also, you might experience chills with or without a fever while the virus runs its course.

Usually, acetaminophen and ibuprofen are both effective fever reducers, but these medications can’t cure the virus.

6. Gastrointestinal problems
Early flu symptoms can extend below the head, throat, and chest. Some strains of the virus can cause diarrhea, nausea, stomach pain, or vomiting.

Dehydration is a dangerous complication of diarrhea and vomiting. To avoid dehydration, drink water, sports drinks, unsweetened fruit juices, caffeine-free teas, or broth.

Flu symptoms in children
The flu virus also causes the above symptoms in children. However, your child may have other symptoms that require medical attention. These can include:

not drinking enough fluids
crying with no tears
not waking up or interacting
being unable to eat
having fever with a rash
having difficulty urinating
It can be hard to know the difference between the flu and a cold in children.

With both a cold and flu, your child can develop a cough, sore throat, and body aches. Symptoms are typically more severe with the flu. If your child doesn’t have a high fever or other severe symptoms, this may be an indication that they have a cold instead.

If you’re concerned about any symptoms your child has developed, you should call their pediatrician.

Emergency symptoms
The flu is a progressive illness. This means that symptoms will worsen before they get better. Not everyone responds the same to influenza virus. Your overall health can determine how severe your symptoms may be. The flu virus can be mild or severe.

Seek immediate medical care if you have the following symptoms:

chest pain
breathing difficulties
bluish skin and lips
severe dehydration
dizziness and confusion
recurring or high fever
worsening cough

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Possible complications
Symptoms of the flu usually go away within a week or two. However, in some cases, the flu can cause additional complications, especially in people at high risk. Some possible complications include:

ear infection
Recovery period
If you’ve been diagnosed with the flu, allow yourself a reasonable recovery period. The Centers for Disease Control and Prevention (CDC)Trusted Source recommends that you don’t go back to work until you’ve been fever-free for 24 hours without needing to take a fever reducing medication.

Even if you don’t have a fever, you should still consider staying home until other symptoms improve. It’s generally safe to return to work or school when you can resume normal activity without getting tired.

The recovery rate varies from person to person.

Antiviral drugs can possibly help speed up your recovery time and make the illness less severe. Even after feeling better, you might experience a lingering cough and fatigue for a few weeks. Always see your doctor if the flu symptoms come back or get worse after an initial recovery.

Protect yourself
During flu season, protecting yourself from respiratory viruses is a top priority.

The flu virus can spread through saliva droplets that are projected when an infected person coughs or sneezes.

These droplets can reach people and surfaces up to 6 feet away. You can be exposed by breathing air containing these droplets or by touching objects that these droplets have landed on.