How does the flu affect the body?

Dr. Jeanne Morrison, PhD
Family Practitioner

Usually, the first effect of influenza (flu) on the body is a fever with chills and muscle aches. You may also have a feeling of general weakness, fatigue, and a headache. Remember, influenza is caused by a group of viruses that infect the respiratory system. As a result, effects on the body often focus on the throat, nose, and lungs. The nose may become congested or runny, the throat may become sore, and a cough may move from dry to wet as the virus runs its course. Sometimes influenza may lead to pneumonia, which can be serious.

Flu, also called influenza, typically causes fever and/or chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and fatigue. Sometimes the flu also causes vomiting and diarrhea, but this is more common in children than in adults.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.