A fever is your body’s defense mechanism, not the enemy itself. The most common mistakes people make when feverish, like jumping into a cold bath, pushing through a workout, or over-medicating, can actually slow recovery or make things worse. Here’s what to avoid so your body can do its job.
Don’t Take a Cold Bath or Ice Bath
This is one of the most instinctive responses to a fever, and one of the worst. When you apply cold water or ice to feverish skin, your body fights back hard. Cold immersion triggers shivering, and shivering raises your core temperature by generating more heat, the exact opposite of what you’re trying to accomplish. Studies show that shivering doubles oxygen consumption and significantly increases your metabolic rate, placing extra strain on a body that’s already working overtime to fight an infection.
Cold water also causes the blood vessels near your skin to constrict, which traps heat deeper inside your body. Research published in Clinical Infectious Diseases found that cold immersion caused “continuous shivering and marked discomfort” and was ultimately counterproductive for lowering temperature. If you want external cooling, lukewarm water is a better option. Tepid sponging or a lukewarm bath allows some heat to escape through evaporation without triggering that aggressive shivering response.
Don’t Exercise or Push Through It
A fever means your immune system is actively mobilizing resources. Exercise diverts blood flow to your muscles, raises your heart rate, and increases your core temperature further. The American Heart Association is clear on this point: never exercise when you have a fever, regardless of whether it’s from the flu, COVID-19, or another virus.
The general rule of thumb is the “neck check.” Symptoms above the neck (runny nose, mild sore throat) may be compatible with light activity once your fever breaks. But symptoms below the neck, like chest congestion, body aches, or stomach issues, are signals to rest. Exercising with a fever also increases your risk of complications like viral heart inflammation, which can develop when the body is pushed too hard during an active infection.
Don’t Bundle Up in Heavy Blankets
When you have a fever, you often feel cold because your brain has temporarily raised your body’s temperature set point. The natural impulse is to pile on blankets. But trapping heat under layers of heavy bedding prevents your body from releasing excess warmth once the fever starts to break. Dress in light, breathable clothing and use a single sheet or light blanket. If you’re shivering, one extra layer is fine, but strip it off once the chills pass.
Don’t Give Aspirin to Children or Teens
Aspirin is linked to Reye’s syndrome, a rare but serious condition that causes swelling in the liver and brain. The risk is highest when aspirin is given to children or teenagers during a viral illness like the flu or chickenpox. The Mayo Clinic is unequivocal: do not give aspirin to anyone under 19 during a fever. Children with certain fatty acid metabolism disorders are at even greater risk. Use acetaminophen or ibuprofen instead, following age-appropriate dosing on the package.
Don’t Overdo Fever-Reducing Medication
Reaching for acetaminophen or ibuprofen every few hours can feel like the right move, but exceeding safe limits carries real risks. For adults, the recommended maximum is 3,000 mg per day for acetaminophen and 1,200 mg per day for over-the-counter ibuprofen. Going above those thresholds can damage your liver (acetaminophen) or kidneys (ibuprofen), especially if you’re already dehydrated from the fever.
A common and dangerous mistake is taking multiple products that contain the same active ingredient without realizing it. Many cold and flu combination products already include acetaminophen, so adding standalone acetaminophen on top of them can push you past the safe daily limit quickly. Always check the active ingredients on every product you’re taking. If you have existing liver or kidney problems, talk to a pharmacist before combining any fever reducers.
It’s also worth remembering that a mild fever doesn’t always need medication. Fevers under about 102°F (38.9°C) in otherwise healthy adults are part of the immune response and often resolve on their own. Treating the discomfort is reasonable, but reflexively suppressing every low-grade fever may not speed up recovery.
Don’t Drink Alcohol or Excess Caffeine
A fever increases fluid loss through sweating and faster breathing. Alcohol and caffeine both accelerate dehydration. The CDC notes that combining alcohol and caffeine increases water loss from the body, and alcohol on its own impairs immune function. Even a glass of wine or a couple of beers can interfere with your body’s ability to fight infection and regulate temperature. Stick to water, diluted juice, broth, or oral rehydration solutions until the fever passes.
Coffee in small amounts is unlikely to cause harm if you’re otherwise well-hydrated, but it’s not a substitute for water. If you notice dark urine, dry mouth, or dizziness, you’re already behind on fluids and should prioritize plain water or an electrolyte drink.
Don’t Wake a Sleeping Child for Medicine
Parents often feel the urge to wake a feverish child every few hours to check their temperature or give another dose of medication. Cincinnati Children’s Hospital advises against this: sleep is more important than the next dose of fever reducer. A sleeping child is a child whose body is recovering. If they wake on their own and seem uncomfortable, that’s the time to offer medication and fluids.
Don’t Skip Fluids or Forget to Eat
Dehydration is the most common complication of a fever, especially in young children. For kids under one year, aim for 1 to 2 teaspoons of fluid every 5 to 10 minutes using a syringe or spoon. For toddlers and older children, the minimum fluid goal increases with body weight. A child weighing 21 to 40 pounds needs at least 6.5 ounces per hour, and those targets go up when fever, vomiting, or diarrhea are present.
Adults should drink enough to keep their urine pale yellow. Small, frequent sips work better than forcing large amounts at once, especially if nausea is a factor. As for food, you don’t need to force a full meal, but light, easy-to-digest options like toast, rice, bananas, or soup provide energy your immune system can use. Starving a fever is a myth.
Don’t Ignore Warning Signs
Most fevers resolve within a few days, but certain symptoms alongside a fever signal something more serious. For infants under three months, any fever of 100.4°F (38°C) or higher requires immediate medical attention, no exceptions.
For older children, look for signs of dehydration (no wet diapers for 8 to 10 hours, crying without tears, dry mouth), a stiff neck, a rash, joint swelling, or a fever lasting more than five days. A child who remains unusually fussy or lethargic even after fever medication has taken effect also needs evaluation.
Adults should seek care for a fever accompanied by difficulty breathing, chest pain, severe headache or stiff neck, confusion, repeated vomiting, abdominal pain, painful urination, skin rash, or trouble swallowing fluids. These can indicate infections or complications that won’t resolve with rest alone.