Science Mom: F***ing Fevers, How Do They Work?

science mom

Fevers aren’t very much fun. They’re miserable, whether you’re a child who doesn’t understand why you feel so poorly or you’re an adult who understands perfectly well but resents it anyway. And of course, when you’re the parent of a sick little one, you want to do whatever you can to make your child feel better. But before you stick a funnel in his mouth to pour liquid Tylenol into, or get him started mainlining Motrin, there are a few facts about what fevers are and how they work that you should be aware of. The gist, however, is this: fevers don’t work exactly how you’ve probably been told they do.

Let’s start with the 98.6ºF myth. 98.6º is the normal body temperature, so if you stick a thermometer into an orifice and get a readout that doesn’t match those three special digits, it’s time to start worrying. You’re a good mom! That’s what you’re supposed to do! Right? Well, no. 98.6º is just the average normal body temp – being concerned that the thermometer says your daughter’s temperature is 99.1º is a bit like getting anxious because your family has exactly 2 children instead of 1.9 like the average American family does. And, well, take it away, Morbo:

morbo averages do not work that way(via)

And not only is 98.6º just an average starting point – any given individual’s personal internal thermostat setting varies by around half a degree every day, with lower temperatures in the morning (before the body’s furnace gets going) and warmer ones toward the end of the day (once you’ve had the engine running all morning and afternoon). And of course, the temperature you end up measuring depends on where, exactly, you jam the thermometer. Rectal temperatures measure higher than armpit temperatures, for example, and oral temperatures fall somewhere in between.

What’s more, a kid’s behavior leading up to the thermometer can affect the number you get, too. If he’s recently been sitting next to the humidifier to help with that nasty cough, the evaporating steam might make his forehead feel a bit cooler to your fancy forehead-scanner. Or if he’s been screaming bloody murder ever since your first failed attempt to stealthily jab the thermometer under his armpit, he might feel a bit warmer than usual: that beet-red face means extra blood, and therefore extra heat, lurking just under the skin.

So the numbers aren’t quite as clear-cut as your middle school biology teacher might have led you to believe, but a good guideline on when to talk to your doctor about temperatures obtained the not-so-good old-fashioned rectal way is: 100.4º for babies younger than three months, and 102º for kids under 3. For your own sad, sickly self, a temperature of 104º is a good time to start getting worried as well as sweaty and sniffly.

And even though numbers involve a lot more hand-waving than you might expect, there is one hard-and-fast rule when it comes to fevers: watching your child’s behavior. A kid with a temperature of 102º who is crabby but subdued is not the same as a kid with a temperature of 102º who is lethargic and who refuses to eat or drink. Numbers are numbers, but a kid who refuses to eat your special homemade macaroni-and-cheese with breadcrumbs and shredded Parmesan on top? That’s serious. (By the way, can I come over for dinner?)

All right, let’s say you have a listless lump of a feverish kiddo on your hands. Now what do you do about it?

An old piece of folk wisdom tells us to ‘feed a cold and starve a fever’. First of all, no, and also, no. Fevers are hard work for the body – depriving a kid of fuel to stoke the fire isn’t a good idea. Feed a cold, feed a fever: perhaps a better piece of folk wisdom to apply is this one, courtesy of grandmothers everywhere: “EAT EAT EAT! You look so skinny! Maybe just one more bite?”

It’s important to remember that fevers aren’t a disease themselves – they’re just a symptom, a way that your body responds to the existential threat of the grody bacteria you picked up at play group last week. Fevers are on your side. Fevers help your immune system work faster and hard; and for certain diseases that can only survive in a very narrow temperature range, a fever may help to bake those bacteria right out of you. So the decision to start fighting a fever instead of letting it fight for you should be based on how miserable you (or your child) feels – not seeing the digital thermometer readout creep up over 100ºF.

By all means, if you’re suffering from the malaise, chills, and general craptasticness of having a fever, medicine is in order. But if you’re more ‘eh’ than ‘EEK’, you may just want to let the thing run its course. It’s not necessary to do liquid Tylenol shots or pop pills to keep your temperature down below 99º, and doing so could actually keep you sick longer if it keeps your immune system from getting down to business. (I now have the “Be A Man” song from Mulan stuck in my head, by the way, so you have to, too.)

Let’s get down to business

to defeat the flu.

Time to take some Motrin

’cause I feel like poo.

Congratulations! You now know How Fevers Work. Use your new knowledge to go forth and prosper, at least as much as it’s possible to prosper when the whole household is down with strep throat. Again.

(Image: itVega/Shutterstock)

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