1. Determine the Onset of Symptoms
The flu and the common cold share many of the same respiratory symptoms, including congestion, sneezing and coughing. The overlap in symptoms makes it tough to diagnose flu. The only way to definitively diagnose the flu is to be tested by your doctor. Short of that, perhaps the most tell-tale sign that you have the flu is the rapid and often severe nature of the onset of symptoms. If you're feeling fine one minute and in the next you feel like you've been hit by a truck, you probably have the flu. With a cold you may feel rundown for a day or two before you develop a runny nose and other symptoms. The onset is gradual. Flu is not subtle. It is marked by a rapid onset of severe, sometimes debilitating fatigue and other classic flu symptoms.
2. Check for Chills
Another way to diagnose flu symptoms is to check for chills. Chills are not a hallmark symptom of the common cold, so odds are that if you have chills you have the flu. Chills very often precede other common flu symptoms, such as runny nose, fever and muscle aches and pains.
3. Take Your Temperature
While it is possible to have the flu and have no or a low-grade fever, most often the flu is accompanied by a high fever. Use a thermometer to take your temperature. A temperature of 98.6 degrees Fahrenheit is considered normal, although some people have a normal temperature that varies by as much as one-half to one full degree higher or lower. If your temperature is elevated several degrees above your normal temperature and you are experiencing other flu-like symptoms, you likely have the flu.
4. Feel the Pain
Determine whether you have muscle aches and where and how severe they are. Cold sufferers frequently experience generalized achiness throughout the body. Odds are you have the flu if you are experiencing other flu-like symptoms and are also suffering localized, severe muscle aches, most notably in the back and legs.
5. Gauge Your Appetite
The adage goes, "Feed a cold, starve a fever." The validity of this folk remedy advice has been long debated, but the truth of the matter is that people with fever often don't feel like eating. It takes energy to digest food. A loss of appetite when experiencing a fever is the body's way of redirecting energy used in digestion to the fight against the virus or bacteria causing the fever. Since fever is one of the defining symptoms of the flu, most people suffering the flu have a corresponding loss of appetite.
