It doesn’t seem like a huge difference to me but even a 1 degree increase of body temp can make you so tired and have fever. Why is that?
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Our body is constantly working to achieve homeostasis. Basically the balance where we exist at the perfect middle ground.
If your internal temp increases due to a virus or whatever then your body instantly begins to fight to return to the normal 98.1 or whatever temp your body stays at. One way to do that is with a fever. This extra work causes you to be tired. You’re not actively doing anything but your body is working overtime inside.
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Your body has an internal set point to maintain temperature. There is some minor fluctuation throughout the day, but usually no more than +/- 1 degree.
When you have an infection, your body may decide to raise the set point. This has the huge benefit of increasing the effectiveness of the immune system.
Mounting an immune response takes up a lot of the body’s resources. This, and the damage being done by the invader, are what make you feel lousy.
Fever is caused by the immune system(white blood cells) releasing chemicals like interleukin 6 and TNF alpha to raise the body temperature for optimal macrophage and NK cell function- these bad boys are the ones which “eat” the bacteria/virus.
The height of fever is an interplay between how strong the host response is – depends of the immune health of host and the immunogenicity of the virus/bacteria.
Like influenza virus typically causes very strong immune response due to the similarity of the virus proteins to human proteins.
The reason you feel like shit are these
1. If you are 70kgs, raising the body temperature by 2 C is going to take 70×2 = 140 Kcal. Imagine keeping it high for 1 to 2 hours. It’s going to use up close to 400Kcal. Imaging running for 45 minutes. You will feel exhausted. And this cycle repeats 2 to 4 times per day.
2. Glycogen is used as an immediate source of energy to raise body temperature in acute infections. Using glycogen uses a lot of water. So you get dehydrated. Add to that the fact that decreasing body temperature entails sweating causing you to lose salt and water.
So loss of energy, water and salt- enough to wipe you out .
3. Even without the thermodynamics , TNF which is a chemical released to cause inflammation- makes you fatigued and lose appetite. My theory is that, in olden times, it was a protective reflex to prevent you from needing to go out and hunt.
Hope that explains it.
A fever is your immune system going crazy bad boys 2 styles blowing up everything to get the bad guy (virus). You feel fatigued because your limited energy gets routed to fund the immune systems loose cannon antics. Go watch osmosis jones and you’ll get the gist of it.
On top of the immune response taking a lot of energy, the body releases hormones that make you tired when you’re sick. I recently listened to a podcast where they discussed how some cases of depression might be the brain over producing those hormones since the symptoms are identical
Slightly off-topic, but the question offers a way to help people understand the effect of 2 degrees increase in the climate being as impactful as it is: compare global warming to a mild fever that’s going to get worse if we don’t do something about it.
Just as a general answer, evolution and nature has made every living thing amazingly complex, so this change really affects us. Pick an animal and look up details about it, you’ll find super crazy stuff where you think nature is just amazing.
If you’re diabetic and have high blood sugar you can get hot. If you have an infection that can cause a temperature as your body works to kill off what ails you. High humidity can make it so the body struggles to produce sweat. The body also uses blood flow and will take blood that’s usually in the organs to transfer heat out of your skin. If it’s very hot, like above your body temperature, it’s easy to overheat especially without adequate hydration. Global warming contributes to this.
Because your body is like the world and a cumulative 2-degree difference is a big difference.
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