Fevers are Good for You!

Or, Learn to Trust Your Body

Evolutionary Medicine

Fevers are misunderstood. They're the misunderstood good guys of our bodies. In fact, without fevers, none of us would be here today. All of our ancestors would have been wiped out, including our non-human ones. No animal, in fact, could survive. That's how important fevers are.

The fever is a way for your body to fight off infections. Its strategy is nothing less than brilliant, because it surprisingly involves a lot of trickery and guile. 

Infections are when something invades your body, sets up camp, and multiplies itself like crazy. Bacteria can enter your throat, find all sorts of food in their for its own growth, leaving children behind, and so forth. They begin to populate your body.

But like all populations, they need more and more food to sustain themselves with. Normally, that would be your own body. Whatever makes you sick is actually eating you alive.

What a fever does, however, is simultaneously encourage the growth of the bacteria, while taking away its food. Bacteria like to grow in warm places (which is why putting food in a refrigerator keeps bacteria and fungi from growing on your food), so when your body temperature rises, it's going to grow more. Bacteria cells don't make a conscious decision about this - they're more machines than man - so if you heat them up, they're going to multiply faster.

Bacteria also need iron to grow. As your body takes away the iron in your blood serum (so any iron that's not already inside your blood cells), bacteria is starved of one nutrient it desperately needs. In combination with your body heat encouraging growth, this imposes a situation of overpopulation on the bacteria in your body. It keeps producing more and more malnourished bacteria, which is easy for the body to take care of. Eventually, the whole population starves and dies.

Raising your body temperature also helps your white blood cells, the police and detectives of your immune
system, to move around your body faster. This means that they can do attack more bacteria (or whatever's ailing you) faster and more quickly.

Fever is so important, in fact, that when you take laboratory animals and deprive them of their ability to have a fever, they're more likely to die when they're fighting off an infection. Likewise, when you simulate fever conditions for those same sick animals, they survive.

Same thing goes with body aches and fatigue. When you're tired and lacking in energy, the first thing to go is your immune system. So when you're sick, and you desperately need your immune system on overdrive, your body is going to do anything it can to shut you down. You'll feel tired and sleepy. Whenever you try to move around, you'll ache. It's all in your brain, but incredibly useful.

So next time you're sick, listen to your body first. Don't automatically reach for the Tylenol or Advil that will reduce your fever, unless you really need it. One study suggests that your fever can go up to 102 degrees without it becoming a real problem. 

For an article about fever by an pediatrician, click here. It's an interesting perspective from the other side - not a patient, but an MD.