Why does breaking a sweat during a fever usually a sign that you’ve successfully gotten over it?



Why does breaking a sweat during a fever usually a sign that you’ve successfully gotten over it?

In: Biology

In my own understanding, since sweat is the body’s natural cooling method, it does just that with fevers and forces the temperature down.

When the fever “breaks”, your body turns down your internal thermostat back to normal. However your body is still at the fever temperature. As your body is still warmer than your normal temperature, you will feel hot and sweat a lot.

It’s not.
Sweats are often associated with high fevers.
The body has set your body to raise the temperature, but the sweat system doesn’t get the message.

Well, it’s not strictly.

But in some circumstances, your body is desperately trying to INCREASE your body temp in order to maintain the fever. This makes you shiver and feel cold and want to wrap up with blankets.

When suddenly, you feel hot and gross and sweaty, it’s your body “turning off” the fever state and you’re going to gradually cool off to your normal body temp.

Your body has a “thermostat” in the brain. The
thermostat has a lot of ways of controlling your core temperature, by either raising it or lowering it. To raise your temperature, it constricts the small blood vessels close to the skin to prevent heat loss, stops you from sweating as much to prevent loss through evaporation, makes your brown fat cells turn fat to heat, and makes your muscles shiver to turn their energy to heat. In order to lower your temperature it makes you sweat, dilates your peripheral blood vessels to lose more heat, and slows down your metabolism to stop you from making more heat.

A fever is your body’s “thermostat” getting highjacked by your immune system in its fight to try to kill whatever has infected you. Your immune system basically convinces your brain that a normal temperature is not 37°C, but instead 38°C or higher. So, your thermostat, sensing you’re at 37°C, thinks you’re too cold, and kicks in the heat.

When you start sweating, it means that the thermostat has realised that perhaps 37°C is a better place to be at, and so it’s lowering your temperature back. That can be because your immune system has won the battle against the bug and is therefore releasing it’s control, or because it *thinks* it’s won when in fact the bug has just hidden for a bit. Therefore, a fever breaking can either mean you’re getting better, or that you’re gearing up for round 2.

The reason people were so relieved by a fever breaking, and still are wherever there’s poor healthcare education, is because a persistently high fever, especially one above 40°C, is directly correlated to a jump in mortality. At that point, your body is burning up it’s resources in trying to keep you that warm, and your own cells are starting to suffer from the heat. This is why stuff like acetaminophen or ibuprofen is such a big deal.

For a less “like I’m 5” explanation, Wikipedia has your back in the pathophysiology section: https://en.m.wikipedia.org/wiki/Fever#Pathophysiology

For a really complex and complete explanation, this paper is a great place to start: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4944485/