Name: Why do you get a fever when you're sick? - Christian Moro
Uploaded: 2020-11-12T18:17:29.000Z
Duration: 5 min 38 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

In 1917, doctors proposed  an outlandish treatment for syphilis,

the incurable bacterial infection  that had ravaged Europe for centuries.

Step 1: Infect patients suffering  from the later stages of syphilis

the deadly but curable  mosquito-borne disease.

Step 2: Hope that malarial fevers  clear the syphilis.

And step 3: Administer quinine  to curb the malaria.

their patient would be left alive  and free of both diseases.

This killed some 15% of patients,  but for those who survived,

It actually became the standard treatment  for syphilis

until penicillin  was widely used decades later.

some birds and even a few invertebrate  and plant species feel fever's heat.

It has persisted  for over 600 million years of evolution.

For every 1 degree Celsius of temperature  increase in the human body,

there's a 12.5 percent increase  in energy required,

the equivalent of about 20 minutes  of jogging for some.

So, why and how does your body  produce a fever?

Your core temperature is maintained  via thermoregulation,

a set of processes that usually keep  you around 37 degrees Celsius.

These mechanisms are controlled  by the brain's hypothalamus,

and sends signals  throughout the body accordingly.

If you're too hot, the hypothalamus  produces signals

that activate your sweat glands  or make your blood vessels dilate,

moving blood closer  to the skin's surface—

all of which releases heat  and cools you off.

your blood vessels will constrict  and you may start to shiver,

Your body will disrupt its usual  temperature equilibrium to induce a fever,

Meanwhile, it has mechanisms  in place to prevent it

from exceeding 41 degrees Celsius, when organ damage could occur.

Immune cells that are fighting  an infection can induce a fever

by triggering a biochemical cascade  that ultimately instructs

your hypothalamus to increase  your baseline temperature.

Your body then gets to work to meet  its new “set point” using the mechanisms

Until it reaches this new temperature,  you'll feel comparatively cool,

which is why you might experience chills.

While the jury's still out on how higher  temperatures directly affect pathogens,

is in rapidly inducing a whole-body  immune response.

Upon exposure to raised  internal temperatures,

some of your cells release  heat shock proteins, or HSPs,

a family of molecules produced  in response to stressful conditions.

These proteins aid lymphocytes,  one of several kinds of white blood cells

that fight pathogens, to travel  more rapidly to infection sites.

HSPs do this by enhancing  the “stickiness” of lymphocytes,

enabling them to adhere to and squeeze  through blood vessel walls

so they can reach the areas  where infection is raging.

HSPs help tell nearby cells to dampen  their protein production,

This stunts the virus's spread  because they depend on

their host's replicative machinery  to reproduce.

It also protects surrounding cells  from damage since some viruses spread

by rupturing their host cells, which can  lead to large-scale destruction,

the build-up of detritus,  and potentially even organ damage.

The ability of HSPs to protect host cells  and enhance immune activity

can limit the pathogen's  path of destruction inside of the body.

But for all we know about fever's role  in immune activation,

some clinical trials have shown  that fever suppressor drugs

This is why there's no definitive rule  on whether to suppress a fever

The fever's duration and intensity,  as well as their patient's immune status,

comfort level, and age will all play  a role in their choice of treatments.

they'll likely prescribe rest and plenty  of fluids to prevent dehydration