- The flu strikes suddenly with severe symptoms appearing within hours, whereas a cold develops gradually over a few days.
- Flu infections often cause a high fever and severe body aches, while colds rarely involve a fever and primarily affect the nose and throat.
- Most flu symptoms improve after one week but fatigue can linger for two weeks, while colds typically resolve completely within 7 to 10 days.
The main difference between a cold and the flu is the speed of onset and the intensity of symptoms. While a cold generally develops gradually over a few days, the flu strikes suddenly and with greater severity.
Generally speaking, flu symptoms are more intense and last longer than cold symptoms. With a cold, the upper respiratory tract (above the lungs) is more affected, while with the flu, the entire lung can be affected.
In addition, flus occur mostly in the winter time and are easily transmissible. A person infected with the flu in a closed room with other people can easily contaminate those around him/her.
The main difference: Sudden vs. gradual onset
Symptoms of the flu typically appear abruptly, often within a matter of hours, which is why patients frequently describe the feeling as being "hit by a truck." In contrast, cold symptoms usually begin with a mild sniffle or sore throat and worsen gradually over the course of a few days.
Understanding this key difference in onset speed can help individuals identify which condition they are likely facing before symptoms progress further.
Difference between a cold or flu
The following table summarizes the main differences between a cold and flu, specifically regarding symptom frequency and intensity:
Another condition called a "flu-like syndrome" can also present similarly to the flu. It can be caused by a flu virus or by another virus or bacteria. Common symptoms include fever, coughing, sore throat, muscular pain and headache.
Symptom stages: Cold vs. flu timeline
Knowing how symptoms progress day-by-day can help manage recovery expectations.
The cold timeline:
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Days 1-2: Sore throat and mild runny nose (gradual onset).
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Days 3-5: Peak congestion, cough, and thicker mucus.
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Days 6-7: Symptoms begin to improve.
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Days 8-10: Mostly recovered, though a cough may linger.
The flu Timeline:
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Day 1: Sudden high fever, chills, severe aches, and fatigue.
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Days 2-4: Peak illness with the most severe symptoms and chest discomfort.
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Days 5-7: Fever subsides, but respiratory symptoms remain prominent.
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Days 8+: Gradual recovery, though fatigue can persist for two weeks or more.
Monitoring these stages allows for better management of the illness and helps determine if recovery is on track.
When to see a doctor
While most cases of the cold and flu can be treated at home, certain symptoms require immediate medical attention.
Emergency warning signs for adults:
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Difficulty breathing or shortness of breath
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Persistent pain or pressure in the chest or abdomen
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Sudden dizziness or confusion
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Severe or persistent vomiting
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Symptoms that improve but then return with fever and worse cough
Emergency warning signs for children:
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Fast breathing or trouble breathing
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Bluish lips or face
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Ribs pulling in with each breath
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Dehydration (no urine for 8 hours)
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Fever above 104°F
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Seizures or lack of alertness
Recognizing these red flags early ensures that complications, such as pneumonia, are treated promptly by a healthcare professional.
How to treat the flu
Treatment for the flu can be initiated with medication as prescribed by a doctor. Acetaminophen can help to lower a fever, while anti-histamines can relieve other symptoms, like a runny nose. Depending on the duration and intensity of symptoms, antivirals, like oseltamivir (Tamiflu), may also be prescribed. Check out other flu medicine that is commonly recommended for treating influenza.
Rest and plenty of fluids (water, tea, broths and fresh juices) are also recommended.
If the infection reaches the lungs and is left untreated, there is a probability for complications like developing pneumonia. Read more about the symptoms of pneumonia, as well as how it is diagnosed and treated.
Read more about how to cure the flu fast using medical and natural treatment.
How to treat a cold
To treat a cold, you may find relief in taking over-the-counter decongestants or anti-histamines.
Taking vitamin C can help to strengthen the immune system and get rid of symptoms faster. You can also consume vitamin C naturally by eating oranges, pineapple, cherries, or strawberries.
Home remedies for a cold or flu
Some great home remedies for the cold or flu are lemon tea with honey and orange juice with propolis extract. These remedies are rich in vitamin C and antioxidants that help to boost recovery.
Other important measures to keep in mind are:
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Bundling up with plenty of clothes
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Keeping your feet warm
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Washing your hands after coughing or sneezing
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Covering your mouth with the crook of your elbow when sneezing or coughing
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Avoiding closed environments
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Avoid eating cold food
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Keeping your nose clear
Learn more about other home remedies for the cold or flu that you can use to complement your medically prescribed treatment.