You know the symptoms:  fatigue or even exhaustion, fever, sore muscles and a headache. But do you have a cold or the flu? You might be surprised to learn how often people mistake the two illnesses.

In the U.S., individuals will suffer one billion colds this year. Though influenza -- often commonly referred to as the flu -- is less common, it can be more severe due to the serious complications it can cause, particularly among the elderly, newborns and those with certain chronic diseases. However, two-thirds of people recover from a cold or the flu within about one week.

Understanding the Symptoms

Both the cold and the flu are respiratory infections caused by viruses. Both are very contagious. But despite the similarities, the symptoms of the cold and flu actually are quite different. 

Someone with a cold seldom has a fever, though this is characteristic for someone infected with the flu virus. Headaches and muscle or joint pains are rare or slight for someone with a cold, but someone with the flu often has severe muscle aches and pains. Cold symptoms usually develop over a day or two, whereas the flu hits hard, with fever and aches developing over just a few hours.

The cold-sufferer may be slightly more tired than normal, but a person with the flu usually shows signs of extreme exhaustion, with fatigue or weakness lasting up to two or three weeks. At the same time, common cold symptoms, such as a sore throat, stuffy nose and sneezing, are only sometimes seen in flu patients.

Common Myths Still Exist

• Neither the cold nor the flu causes nausea, vomiting or diarrhea, although the appetite can be affected by both. The illness that people sometimes call "stomach flu" is not influenza and requires different medical treatment. 
• It’s also true that though most colds and the flu occur during the fall and winter seasons, they are not caused by the cold weather. When the weather turns chilly, people do tend to spend more time indoors, increasing their chances to spread the virus. Cold weather may also dry the lining of the nasal passages and make them more vulnerable to infection.
• There’s no real way to prevent a cold, though many people try to do so by taking large quantities of Vitamin C or even inhaling steam. Annual flu vaccinations can help prevent influenza, and they are particularly recommended for those in high risk categories. Good hand washing also can help decrease the spread of both cold and flu.

Contact Your Physician if Symptoms Persist

So let’s get back to our original question. You should now be able to predict with some degree of confidence that the symptoms described at the beginning of this article are more typical of someone suffering from the flu rather than a cold. Unfortunately, for treating the flu, you sometimes just have to wait it out and treat the symptoms. You should contact your physician if your symptoms persist or a secondary infection develops. About 5 percent of patients with cold or flu can develop secondary bacterial infections, such as pneumonia or sinusitis, requiring the use of antibiotics.