As the flu season progresses, so does the chorus of advice, professional and otherwise, to drink plenty of fluids and take fever-reducing medications such as paracetamol, ibuprofen or aspirin.
These recommendations, well-intentioned and firmly established, provide comfort to those sidelined by fever, flu or vaccine side effects. But you might be surprised to learn that the science supporting these recommendations is speculative at best, damaging and caveat-laden at worst.
I am an exercise physiologist who specializes in studying how the body regulates fluids and temperature. And based on a large body of evidence, I can tell you that increasing fluid intake and taking fever reducers, whether aspirin, paracetamol or ibuprofen, will not always help your recovery. In some cases it can even be harmful.
There is a reason why people say fevers should be lowered when they are sick or after a vaccine. Both aspirin and acetaminophen, such as Tylenol, reduce fever, headache, and muscle aches. But at the same time, groundbreaking and newer research, including broad meta-analysis studies, shows that these drugs may weaken the immune response to infections or have unwanted side effects.
What is fever?
First, some background: Fever is a regulated increase in the body’s core temperature in response to unwanted microbial invaders. The more severe the infection, the higher the fever.
Having a fever is not all bad; it’s how the body evolved to recover from an infection. For many species, fever is beneficial and beneficial to survival.
But fever comes at a cost. Too high a body temperature can be fatal. For every 1.8 degrees Fahrenheit increase, metabolism increases by 10%; the body begins to burn more calories than normal, the temperature continues to rise, and the body releases hormones to control the fever.
Many studies show what can happen when fever reducers are inserted into this complex dance. It turns out that aspirin or acetaminophen can make infected people feel better, but they also spread more virus while suppressing their own immune response to the infection.
In a double-blind, placebo-controlled study, healthy people infected with a cold virus who took aspirin or paracetamol for a week had a reduced immune response and an increase in virus excretion – meaning virus particles were produced and expelled from the nose. Another study showed that taking aspirin effectively reduced fever symptoms but increased excretion.
Although some of these traditional studies took place decades ago, their results are still relevant today. A recent study warned that if everyone took fever suppressants, there would be even more flu cases and flu-related deaths. Additionally, an elevated body temperature – or fever – can help fight COVID-19 by reducing the growth of the virus in the lungs. In other words, fever can help the body fight viruses while reducing deaths and illnesses.
Drink fluids
To prevent dehydration, the Centers for Disease Control and Prevention recommends drinking more fluids if someone has a fever, infection, or has received a COVID-19 vaccine. But there is little scientific evidence to support this recommendation.
It is true that drinking fluids when you are dehydrated is necessary to reduce fever. But not everyone with a fever is dehydrated. For those who are not thirsty, it may not be advisable to force fluids beyond thirst, which is often unpleasant.
[Get fascinating science, health and technology news. Sign up for The Conversation’s weekly science newsletter.]
A study evaluating the advice to ‘drink plenty of fluids’ found that increasing fluid intake during illness may not provide benefits, and that more high-quality studies are needed. There was indeed a potential risk of overhydration. For some people, three liters, or about twelve eight-ounce glasses, is too much. Overhydration can cause nausea and vomiting, headaches and cramps; in severe cases, excessive fluid intake can cause seizures or coma.
This is why this happens. To prevent dangerous escalations of fever, the body releases antidiuretic hormones. Urination is reduced so that the body retains water through the action of the kidneys. So if someone with a fever drinks more water than necessary, water intoxication – or hyponatremia, a potentially fatal medical condition in which sodium levels in a patient’s blood are too low – can result.
One study found that almost a quarter of patients who came to the hospital with COVID-19 had hyponatremia on admission. In that study, hyponatremia increased the need for respiratory support in the form of ventilation. And another study showed that the condition can lead to worse outcomes in COVID-19 patients.
So maybe it’s time to reconsider the conventional wisdom. If the fever is mild or moderate, stay warm and even use blankets, rather than trying to actively reduce it. Rest so your body can fight the fever. Save energy, because your metabolism is already running at full speed. Use fever-reducing medications sparingly. Drink fluids, but only if you tolerate it, and preferably when you are thirsty.
And one last suggestion that should be soothing: When combating fever or vaccine side effects, consider drinking warm fluids that contain sodium. Broths containing sodium, such as precious metal, can help prevent hyponatremia. And while the actual scientific evidence is scant and conflicting, chicken soup may be a better antidote than water in warding off fever or flu symptoms.
This article is republished from The Conversation, an independent nonprofit organization providing facts and trusted analysis to help you understand our complex world. It was written by: Tamara Hew-Butler, Wayne State University
Read more:
Tamara Hew-Butler does not work for, consult with, own shares in, or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.