- Babies just sit there and they're like.

- Babies are like, "Yeah, man, Dr. Patel, gimme that spinal tap!"

- They're like, "Give me sugar water in my pacifier and you can do whatever you want, I don't care."

(cheerful music) - So what's happening in my kids when they have a fever?

Like what's happening in their little bodies?

- In their little bodies?

So basically, their immune systems are setting up the right scenario to go to battle.

(dramatic music) Pyrogens, pyrogens are these chemicals that are released by either the foreign invaders, bacteria, viruses, themselves, or triggered from the immune system to the hypothalamus.

- Sounds like pyromaniacs.

- Kinda like that, right?

- [Unison] Fire, fever.

(flames billowing) - But pyrogens will go to your hypothalamus.

(whistling music) Hydrogens will go to your hypothalamus and drive up the body's temperature.

Now, experts think that at a slightly elevated temperature, the chemical reactions used by the immune system are more efficient.

And so the immune system almost gets a competitive advantage over foreign invaders, like some microorganisms, which don't fare so well at higher temperatures.

You see a lot of this in the animal kingdom.

Lizards, sometimes will even crawl to a place where they can elevate their body temperature to fight off infections.

- [Bethany] Like a hot rock.

- [Alok] Like a hot rock.

- What about when my kids are shivering and shaking from fever, what's happening there?

- Basically your body's internal thermostat has a new, almost like a new set point, right?

And your body's like, "This is where I wanna be."

But the rest of your body is not quite there yet.

The body will react by trying to also generate heat and so shivering, feeling the chill, so you go and grab blankets, because your body's basically trying to warm itself up to get to the new set point.

Everything is whack, (chuckles) but it's all in the name of competitive advantage for your immune system over the foreign invaders.

- Competitive advantage.

- Competitive advantage.

But while your body's achieving this-- - That's a good rebranding of fever.

Like if fever got a PR company and fever was like, "I don't know, like I kind of have like a bad image.

Like, can we do something about that?"

And like a good PR person would be like, "How about competitive advantage to like, you know, defeat invaders?"

Fever's like, "Yeah!"

(flames billowing) (bell ringing) So this, I feel, is like a mixed message that I'm always hearing.

(peppy music) On the one hand, fever is a sign that your body's doing what it's supposed to do to fight an infection.

- Totally.

- On the other hand, we're told to reduce fevers.

Like, which is it?

What am I supposed to be doing?

Letting the fever do its job, which is what I do, (gasps) or reduce the fever?

- I don't think it's a bad thing to let fevers do their jobs, because again, fevers have a certain protective measure to them.

Again, there's a threshold.

We wanna make sure we understand the underlying reason why your kid has a fever and that it's safe to let it run its course.

- What are some methods to reducing fever?

I know you can use ibuprofen or acetaminophen.

How about ice baths?

My grandmother used to threaten me with ice baths.

Like, is that still a thing, or is that like back in the day?

Is that Model T Fords and ice baths?

(Alok laughing) Do you do that anymore?

No more?

I don't know if we do the full-on, like professional football player, ice bath, but it's certainly okay to try like a cooling towel, (laughs) or to lower the temperature.

- [Bethany] A cooling towel.

- Just to kind of make things a little bit more comfortable.

- That's a nice compromise.

- Because here's the thing.

If you've checked in with your doctor and you feel like it's safe and it's okay to drop the fever, I get it.

Fevers make children uncomfortable, their hearts rate a little faster.

They seem fussy.

You might wanna make them feel more comfortable.

Experts think acetaminophen may work directly at your body's thermostat, the hypothalamus, to drop the core temperature, and ibuprofen may block the chemical signals which go there.

So they both essentially work in the same end point.

They tend to work differently in certain children.

- When is it super serious?

Like when do you really, really have to worry about a fever?

- So I know I've harped on this like 15 times, but if your child looks sincerely ill, or is not acting like themselves, I don't even care what the temperature is, you should check in with the doctor.

But specifically talking about a fever, any fever, any fever in young babies, especially under three months, is serious unless proven otherwise.

And I say serious because in young babies, they're at a higher risk for getting really bad infections that can affect the brain.

It might necessitate blood tests or even a spinal tap, which is not a big deal in babies.

They take it like champs.

(Bethany groaning) I promise.

- How do you know that?

- I've done them, and babies just sit there and they're like-- - And the babies are like, "Yeah, man, Dr. Patel, give me that spinal tap."

- They're like, "Give me sugar water in my pacifier and you can do whatever you want, I don't care."

'Cause here's the thing.

- What's the thing?

- If people were to call doctors for every single fever, we would get called nonstop because kids get fevers all the time, and the majority of infectious fevers, meaning fevers caused by an infection, are from viruses.

These are mostly things like the common cold, not very serious, but some virus infections can be dangerous.

So it's always best to keep a child with a fever at home and to protect yourself with basic hygiene, especially hand-washing.

The fever, a fever, temperatures, they're all a symptom.

They're not themselves-- - They're not the illness.

- They're not the illness, exactly.

- It's not the thing you're worried about.

- It's not the disease, it's a symptom.

So the things that are gonna cause a fever.

So you're talking about infections, like ear infections, pneumonia, UTI, things like that.

You also have chronic disease, rheumatologic disease, auto-immune, auto inflammatory conditions.

Even certain medications, vaccinations.

These can all cause fevers.

- A love fever, that's not legit fever.

- Not a legit fever.

- What about spring fever?

- Not spring fever.

- All right, go back to real fever, I'm sorry.

Go back to real fever.

- Also not teething.

You can get a slightly, maybe a little bit of an elevated body temperature, but you're not gonna get into fever category.

- Teething is because the baby's teeth are real busy coming out, right?

That's more like, (panting).

The teeth trying to come out (panting).

- Possibly.

- And so they were a little bit warmer.

- But it's a cool process inside the body, when your immune system actually needs to tell you to get a fever.

- All right.

I like when you're just like, "I'm going to keep talking, Bethany, 'cause you're not making sense."

(Alok laughing) - Alok, stop, stop doing yoga.

Stop with the yoga.

We just came back, stop with the yoga.

- I'm just in the mood.

It's just like my body's flowing.

I got good energy.

- This is good.

- Yeah!

- This thing is good.

You can't stop.

Can't stop, won't stop those yoga poses.

- Addicted to hot yoga.

(swirling music) (digital tones music)