First Symptoms of a Flu

Today's common flu virus is defined as a viral infection that affects the respiratory system of the body. Once someone is exposed to the virus, the body will begin to "fight off" the infection, prompting initial flu symptoms.

Fever

• The most common symptom initially manifests in a person with the flu is a fever. Typically, the fever is moderate to high in nature, running anywhere between 100 and 104 degrees Fahrenheit, and will be present throughout the duration of the infection. That being said, some people will actually suffer from a higher fever at the very onset of exposure, peaking upwards of 106 degree Fahrenheit before decreasing to a more average range.

Aches

• Aches often accompany fever during the initial onset of flu symptoms. Aches affect fever muscles throughout the body and are more severe in some areas than other. Acetaminophen or ibuprofen are the only over the counter drugs that can assist with these aches, but in most cases, flu sufferers report no real relief until the infection begins to subside.

Cough

• Since the flu is a respiratory infection, the virus can cause some irritation within the lungs and bronchial passageways of sufferers. When this happens, a person is likely to have an unproductive cough, meaning it will lack the production of mucus. This can occur even at the onset of infection and is frequently associated with a sore throat, due to the frequency of coughing.

Fatigue

• For most people, the fever, ache, cough and sore throat comes with a great level of fatigue. This fatigue is largely due to the immune system's response to the virus. As soon as someone is exposed to the influenza virus, the body reacts with its immune system to "fight off" the infection. Since the body is now working harder than usual, a person's energy level is adversely affected, resulting in fatigue.

Headache

• It is also quite possible for a person to suffer from a moderate to severe headache with the onset of the flu. In this situation, a person would experience what is called a secondary headache, meaning it is the virus that triggers the activity of those nerves in the brain responsible for "pain-sensitivity."

Congestion

• Most people suffering from the flu also experience some congestion. Again, this is the result of the virus causing irritation and inflammation within the respiratory system, including the membranes of the nasal passages. In most instances, this causes congestion as well as a runny nose.

Other Symptoms

• As the flu works it way through the sufferer's system, it is possible for people to experience other signs and symptoms. This may include an chills, night sweats, loss of appetite and some diarrhea and/or vomiting.