Shivering during a fever is your body’s way of generating heat, and the fastest way to stop it is to work with that process rather than against it. Layering on blankets, taking a fever reducer, and staying hydrated will address the shivering directly. But understanding why it happens helps you avoid common mistakes that actually make it worse.
Why Fever Causes Shivering
Your brain has a built-in thermostat, located in a region called the hypothalamus. When you get an infection, your immune system releases signaling molecules that raise the hypothalamus’s target temperature. Instead of the usual 37°C (98.6°F), your body may now be aiming for 39°C or higher. The problem is that your actual body temperature hasn’t caught up yet. Your brain perceives that gap the same way it would perceive being outside in the cold: it triggers shivering to generate heat through rapid muscle contractions.
This is why you can feel freezing cold even though your skin is warm to the touch. Your body isn’t actually cold. It just thinks it is, relative to its new, higher set point. Shivering stops once your core temperature reaches that new target, which is also when you start to feel the “hot” phase of a fever. Shivering can increase your body’s oxygen consumption by roughly 50% or more compared to resting levels, which is why it feels so exhausting and leaves you drained even before the fever fully sets in.
Layer Blankets to Close the Temperature Gap
Since shivering is driven by the mismatch between your current temperature and your brain’s new set point, the most immediate relief comes from warming up. Add a blanket or two and wear comfortable clothing. This helps your body reach its target temperature faster, which signals the hypothalamus to stop triggering shivering. You don’t need to pile on every blanket in the house. One or two layers on top of your normal bedding is usually enough.
Once the shivering stops and you start feeling warm or sweaty, remove the extra layers. Keeping them on at that point traps heat and can push your temperature uncomfortably high. Think of it as two phases: bundle up while you’re shivering, then lighten up once you’re not. Keep the room at a comfortable temperature rather than cranking the heat. Lightweight, breathable clothing works best for the duration of the fever.
Use a Fever Reducer
Fever-reducing medications work by lowering the hypothalamus’s set point back toward normal. Once that set point drops, the gap disappears, and your body no longer has a reason to shiver. Acetaminophen and ibuprofen are both effective options.
For adults and teens weighing 50 kg (about 110 lbs) or more, acetaminophen can be taken at 1,000 mg every six hours or 650 mg every four hours, with a maximum of 4,000 mg in a day. For adults under 50 kg, the dose is weight-based at 12.5 mg per kg every four hours or 15 mg per kg every six hours. The same weight-based calculation applies to children ages 2 to 12. Ibuprofen is another option and can be alternated with acetaminophen if one alone isn’t bringing relief. Always follow the dosing intervals on the package and avoid doubling up.
These medications typically take 30 to 60 minutes to kick in. In the meantime, blankets are your best tool for comfort.
Stay Ahead of Fluid Loss
Fever increases the amount of water your body loses through your skin. As a general guideline, fluid needs rise by about 10% for every degree Celsius your temperature climbs above 38°C (100.4°F). If you’re shivering, sweating, or both, you’re losing fluid faster than usual.
Water is fine for most people, but adding something with electrolytes (a sports drink, broth, or oral rehydration solution) helps if you’ve been feverish for more than a few hours or aren’t eating much. Sip consistently rather than trying to drink large amounts at once, especially if nausea is an issue. For children, small, frequent sips or ice pops work well.
Avoid Cold Water and Ice Baths
One of the most common mistakes is trying to cool down with cold water, ice packs, or a cold bath. This backfires. When cold hits your skin, your hypothalamus detects an even bigger gap between your current temperature and its set point, and it responds by intensifying the shivering. You feel worse, your muscles work harder, and your temperature may actually climb.
If you want to use a sponge bath, stick to lukewarm water between 32°C and 35°C (90°F to 95°F). This can help with comfort without triggering more shivering. If shivering starts during the sponge bath, stop immediately. Rubbing alcohol on the skin is an old home remedy that should be avoided entirely, as it cools the skin too rapidly and can be absorbed through the skin.
When Shivering Signals Something Serious
Most fever-related shivering is uncomfortable but harmless. It accompanies common infections like the flu, colds, and stomach bugs, and it resolves as the illness runs its course. However, there’s a difference between mild chills and full-body shaking that you can’t control, sometimes called rigors.
Rigors, the kind of violent, teeth-chattering shaking that makes the bed move, are more closely associated with bacterial infections in the bloodstream. Research in the British Journal of General Practice found that shaking chills had a specificity above 90% for predicting bacteremia, meaning that when someone has true, intense rigors, there’s a meaningful chance of a serious infection. Mild chills were far less predictive. This doesn’t mean every episode of hard shivering is dangerous, but it’s a signal worth paying attention to.
Seek medical attention if shivering and fever are accompanied by confusion, rapid breathing, a rash that doesn’t fade when pressed, severe headache with neck stiffness, or if the fever persists above 39.4°C (103°F) for more than two days. In infants under three months, any fever warrants a call to a doctor regardless of whether shivering is present.
Putting It All Together
The sequence that works best for most people is straightforward. Take a fever reducer as soon as you notice shivering and fever together. While waiting for it to take effect, add a blanket or two and wear comfortable layers. Sip fluids steadily, aiming for a bit more than you normally would. Avoid anything cold on the skin. Once the medication kicks in and the shivering stops, switch to lighter clothing and keep the room comfortable. If the fever cycles back and shivering returns, you can repeat the process within the dosing guidelines on your medication.
Rest matters too. Shivering is metabolically demanding, burning through energy reserves and leaving your muscles sore. Sleep and rest give your immune system the best environment to do its job, and they’re the reason most fevers resolve on their own within a few days.