November 2025 - Magazine - Page 133
November 2025
reduced blood levels of iron and zinc, reduced appetite and overall lethargy, this forces us
to focus on rest and recovery.
Animals as diverse as fish and reptiles also raise their core temperatures during infection for
better survival outcomes (cold-blooded animals do this by physically changing their environment to warmer climates: fish swim to warmer waters and lizards bathe in the sun). Fever
has been found to give organisms, including people, a better chance of surviving infection.
Too much fever
If our bodies are unable to mount an inflammatory response, such as fever, swelling or redness, we cannot adequately protect the body from infections.
Still, in the case of both inflammation and fever, "a bit is good, too much is bad", says Perretti.
Because fevers can certainly also be dangerous. Persistent high temperatures can lead to
dehydration, as our bodies increase the production of sweat to cool us down. If our body
temperature gets too high, and stays above 40C (104F) for too long, our vital systems stop
functioning correctly. A 2024 study of mice, meanwhile, found that excess heat can lead to
DNA damage.
In the case of mild fevers, it can be better in some circumstances to let them
do their job – Mauro Perretti
Another concern is febrile seizures, convulsions which primarily impact young children. These
are the body's response to a rapid surge in its core temperature, usually when fighting an
infection. The exact cause isn't fully understood. Most febrile seizures are unlikely to harm
you or cause long-term effects, but it is important to still be checked by a doctor.
Serious complications occur, though, when persistent high fever is ignored as a warning sign
of harmful conditions such as meningitis, pneumonia or sepsis. Given this, treating microbial
infections with the correct course of action suppresses our need to produce pyrogens and
adjust the body's thermostat, since it gets rid of the foreign bodies our immune system
would be fighting.
Fever is a powerful but sometimes lethal instrument the body uses to fight infection and protect us. One instance when things turn for the worse is during uncontrolled extremely high
fever, known as hyperpyrexia. Such uncontrolled heat can lead to brain dysfunction and
even organ failure, both of which can be deadly.
To treat a fever?
So, considering fever is usually helping our bodies fight infection, what happens when we try
to get rid of it?
There certainly are potential downsides. As a 2021 review of fever in the Covid-19 pandemic era put it: "blocking fever can be harmful because fever, along with other sickness symptoms, evolved as a defence against infection".
Using medication to quell the impacts of fever can also have adverse effects at a population level. A 2014 study, for example, found that suppressing fevers caused by the flu can
lead to higher transmission rates. That's because if infected people simply treat their feverish
symptoms, they soon resume their everyday activities, from work to socialising, spreading
the disease further than if they felt the need to rest.
In the case of mild fevers, it's therefore better in some circumstances to let them do their
job, says Perretti. Theoretically, he says, one could give the body 24 to 48 hours to perform
the necessary inflammatory response. However, he warns, this could still be dangerous in
some situations, so you should always consult your clinician, who can identify the best
course of treatment for your specific scenario.
Scientists are still working out when to treat fevers, and when to leave them alone. But the
next time you have one, as the sweat drips from your body and the shivering
sets in, take the opportunity to marvel at your immune system's efforts to protect you from further harm. It's been millennia in the making.
