What Are the First Signs of the Flu?

Early Symptoms of Flu

Symptoms of the flu can include high fever (over 100.4 F or 38 C), body aches, chills and sweats, headache, cough, fatigue and weakness, nasal congestion and sore throat.³ Below, we’ll go through a few of these common symptoms so you know what to expect.

1. Sudden Fever

A quickly developed fever of 100.4 F or 38 C or more is a very common early symptom of the flu. However, not everyone with the flu will have the fever. You can have a varying combination of symptoms that can signal the flu.

2. Chills

If you've ever felt cold, shivery and clammy even while under blankets in a warm house, you were probably experiencing chills. Chills and body shakes are a common first sign of the flu and often accompany fever. 

3. Generalized Muscle Aches

Another early symptom of flu is generalized muscle aches. This symptom can present when you suddenly develop muscle aches throughout your body that aren't associated with any excessive exercise or injury.

4. Headache

If you find yourself with a headache along with other symptoms like body aches and a fever, this can be a sign of an oncoming or ongoing bout of the flu.

5. Fatigue

Fatigue can be an early flu symptom as well as a lingering one. General fatigue and tiredness can signal a developing flu virus and it often stays with you for days after the majority of your flu symptoms leave.

Other flu symptoms that may come later include cough, runny nose, nasal congestion, and sore throat.¹ There are some more serious flu symptoms you should also watch out for if you or someone in your family encounters them. They include difficulty breathing, persistent pain in the chest or abdomen, not urinating, worsening of chronic medical conditions, seizures, and more.⁵ If you present any of these symptoms or are at risk of complications, see your doctor right away.

Why is it important to recognize the first signs of flu?

Because the flu is a serious, highly contagious illness, it's important to recognize the first symptoms so that you can help prevent it spreading to other people. You can actually spread the flu before you know you're sick as well as during. People are the most contagious 3-4 days after the flu begins, but may be able to infect others one day before symptoms begin and up to 5-7 days after getting sick.¹ Once you know you have the flu, take steps to stay away from other people, cover coughs and sneezes and wash your hands with soap and water frequently to help slow the spread of germs.

When you recognize these early symptoms in yourself or your family members, you can get a flu test from your doctor. It is important to get a flu test to confirm whether you have the influenza virus because it can be difficult to distinguish it from other viral or bacterial respiratory illnesses based on symptoms alone.¹ With a flu test, you can confirm whether you have the flu, get appropriate care and medication from your doctor, and distance yourself from others to prevent passing the flu virus. Getting a flu test is an important step so you can help get diagnosed soon and get the right care!

Another important, and perhaps most vital, step to flu care is taking preventative measures like getting the flu vaccine every year. According to the CDC, the flu vaccine is shown to reduce flu related illnesses and the risk of serious flu complications that can result in hospitalization or even death.⁸ You can get a flu vaccine through your healthcare provider and many insurance policies assist in covering costs for the vaccine. Ask your doctor what the best type of flu vaccine is for you and your family members young and old.

Now that you know the first signs of flu, you can keep an eye out for any sudden symptoms. Explore the Theraflu Power Living center to learn more and rely on Theraflu products to help relieve your worst cold and flu symptoms.