You get up in the middle of the night and your head is throbbing; your throat is sore. You also feel warm, but don’t think you have a fever. You start to wonder: “Is it cold or flu?” If you knew, it would make the decision to call off sick a little easier.
In fact, there are more than 200 different viruses that can cause colds, but the most common is called rhinovirus. You don’t catch a cold by going outside with a wet head (sorry, Mom) or running out to your car in the winter without a coat. It’s passed to you from someone else. A common cold typically doesn’t last more than a week, but according the Centers for Disease Control and Prevention, it is the main reason kids miss school and you miss work.
Flu is more serious. Thousands of people die and up to another 200,000 people are hospitalized each year because of it. It is contagious, lasts a week or two, and can have lingering effects. As many as 20 percent of us will get the flu this year, but less than half of us will get a flu shot.
That’s why it’s so important to know when you have a cold or flu.
To do a quick symptom check for influenza think "F.A.C.T.S." That stands for fever, aches, chills, tiredness and sudden onset:
A fever is a sign that your body is fighting off an infection. Flu-related fevers are typically 101˚F or higher. Viruses thrive at your normal body temperature of 98.6˚F, so when your body is hotter it's harder for the flu virus to survive. The warmer temperature also stimulates your immune system.
It happens a lot. You think your body aches are from that spin class the night before. But what is actually happening is your body is releasing chemicals to help white blood cells fight off the infection. Like a fever, it’s actually a good sign, but the side-effect is soreness.
There’s a chance you will not have a fever. You might experience chills, with or without a fever, while the virus runs its course. Chills are caused by rapid muscle contraction and relaxation. They are your body's way of producing heat when it feels cold.
Your immune system is working so hard to fight the virus, you feel tired and your muscles may even lose strength. Tiredness is also one of the symptoms that may linger after your other symptoms disappear.
Sudden onset may be the tell-tale sign you have the flu. It is a trademark symptom of influenza, whereas colds usually begin with a stuffy nose or sore throat and then progress gradually.
What sets a cold apart is that you will most likely feel it coming on. The symptoms you’ll gradually experience include:
Colds and flu are no fun. Your best bet is to try to avoid them altogether by doing things like: getting a flu shot, washing your hands, and exercising to keep your body’s immune system strong.
You can also download our guide: “How To Get Rid of the Flu or Not Get It At All.” It includes the five most important flu prevention tips.