Why IV fluids make you feel cold
IV fluids make you feel cold because they are usually given at room temperature, well below your body's average of 98.6 °F (37 °C), so your body has to warm every milliliter. Anesthesia teaching material estimates that each liter of room-temperature fluid lowers average body temperature by about 0.45 °F (0.25 °C). The arm with the IV usually feels coldest first.
Why do IV fluids make you cold?
Your body keeps its core close to 98.6 °F (37 °C), according to MedlinePlus. An IV bag hanging in a patient room or clinic sits at the temperature of the room, which is much cooler. As that fluid enters a vein, your blood gives up heat to bring it up to body temperature, and that heat has to come from somewhere.
The effect adds up with volume. A University of Michigan anesthesiology lecture on heat balance, published by the Multicenter Perioperative Outcomes Group, puts the cost at about 0.45 °F (0.25 °C) of average body temperature for each liter of crystalloid (salt-based fluid such as saline) given at room temperature, and the same for each unit of blood given straight from the refrigerator.
A slow drip of a small volume rarely moves your temperature much, but it can still feel chilly. A fast bolus, several liters during surgery, or fluids given while you are lightly dressed and lying still can make the difference you notice. Sedation and anesthesia also blunt the body's usual defenses against cooling, which is why surgical teams track temperature closely.
Why does my IV arm feel cold?
The vein that receives the fluid is cooled first, and so is the skin above it. Cool blood travels up the arm before it mixes with warmer blood in the chest, so many people feel a cold line running up the forearm or a chill in the whole arm. That arm is also often left uncovered so staff can see the site.
A cold arm is usually just physics, but it can also be a sign that the IV has slipped out of the vein and fluid is collecting under the skin (infiltration). St. Jude Children's Research Hospital lists swelling, a tight or puffy feeling, pain near the site, skin that feels cool to the touch, and redness or a pale color as signs to report to the care team right away.
| What you notice | Likely meaning | What to do |
|---|---|---|
| Cool feeling along the vein, arm chilly, site looks normal | Room-temperature fluid cooling the vein and skin | Ask for a warm blanket and cover the rest of the arm |
| Cool skin plus swelling, puffiness or pain at the site | Possible infiltration (fluid leaking under the skin) | Tell the nurse right away; do not wait for the bag to finish |
| Shaking chills with fever, or feeling very unwell | Possible infection or reaction, not just cool fluid | Call staff now; see the warning signs below |
Do hospitals warm IV fluids?
Often, when the volume or the setting calls for it. A Cochrane review of 24 trials with 1,250 adults having surgery compared fluids heated to between 98.6 and 105.8 °F (37 and 41 °C) with room-temperature fluids. Warmed fluids kept core temperature about 0.9 °F (0.5 °C) higher and reduced shivering.
The same review cautions that the benefit may be small when patients are already warmed in other ways, such as with a heated air blanket. Warming is done with dedicated fluid-warming devices that control the temperature. A routine drip on a ward or in an infusion chair is often not warmed, because the volume is small and the cooling is mild.
Never try to warm an IV bag yourself in a microwave, under a heating pad or with hot water. A review of burns from body heating devices in the journal Wounds lists warmed IV bags among the causes of skin burns, alongside hot water bottles and heating pads.
What can you do if an IV makes you cold?
Small steps make a real difference, because most of the chill comes from the fluid and from lying still in a cool room.
Ask for a warm blanket early, before you start shivering. Many units keep warmed blankets ready.
Cover the rest of your IV arm loosely and keep the site visible, or ask the nurse how they want it covered.
Wear warm socks and keep your head and neck covered; a hat or hood helps when the room is cool.
Choose a top that opens at the sleeve or front so staff can reach the line without you undressing.
If you are allowed to drink, ask whether a warm drink is fine for you.
Do not place hand warmers, heat packs or heating pads on the IV arm. A numbing cream, nerve block or reduced sensation can stop you from feeling a burn, and the Wounds review found that people with reduced sensation are at higher risk.
When to call a clinician or emergency services
Feeling cool during an IV is common. Some signs point to something else, so tell a nurse or clinician straight away if you notice any of the following. After discharge, call your care team or emergency services if they appear at home.
A temperature above 100.4 °F (38 °C), which MedlinePlus describes as generally indicating a fever.
Shaking chills, fever or feeling very unwell during or soon after a blood transfusion.
Swelling, pain, coolness, redness or a pale color at the IV site (St. Jude).
Fever, shivering or feeling very cold together with confusion, clammy skin, extreme pain, a fast heart rate or shortness of breath; the CDC lists these as signs of sepsis, a medical emergency.
Key takeaways
IV fluids are usually given at room temperature, so your body has to warm them to about 98.6 °F (37 °C).
Each liter of room-temperature crystalloid lowers average body temperature by roughly 0.45 °F (0.25 °C).
Warmed fluids keep surgical patients slightly warmer and reduce shivering; hospitals use controlled fluid warmers.
A cold arm is usually normal, but cool skin with swelling or pain at the site needs a nurse's check.
Never warm an IV bag yourself or put heat packs on the IV arm.
Frequently asked questions
Why does my IV feel cold going in?
The fluid is usually at room temperature, which is far cooler than your blood. The vein and the skin above it cool first, so you feel a cold line up the arm. It fades once the infusion slows or stops.
Do IV fluids lower your body temperature?
A little, depending on volume. Anesthesia teaching material estimates about 0.45 °F (0.25 °C) of average body temperature per liter of room-temperature fluid. Small drips barely change temperature, but large volumes during surgery can, which is why fluids are often warmed there.
Can I ask for my IV fluids to be warmed?
You can ask, and you can always ask for a warm blanket. Whether fluids are warmed depends on the volume, the setting and the equipment available, so your nurse or clinician will decide what fits your care.
Is it normal to shiver while getting IV fluids?
Mild chills from cool fluid in a cool room are common, and a warm blanket usually helps. Shaking chills with a fever, or chills during a blood transfusion, are different and should be reported to a nurse right away.
Why does a saline flush feel cold?
A flush pushes a small amount of room-temperature saline quickly through the line, so you briefly feel the cool fluid in the vein. The feeling usually passes within moments. Tell the nurse if a flush causes pain or swelling at the site.
Can I put a hand warmer on my IV arm?
It is safer not to. Heat packs can burn skin, especially if a numbing medicine or nerve block has reduced feeling in that arm. Ask for a warm blanket instead, and let staff manage any warming near the line.
From HEATJAC
We design low-profile thermal garments: a heat-reflective vest and a thermal harness with pockets for warmers or cold packs. If you have reduced sensation or a health condition, check with your clinician before adding heat.
Choosing gear? Before you buy: a checklist for any warming garment · Are heated vests safe?
Related reading
Sources
Warming of intravenous and irrigation fluids for preventing inadvertent perioperative hypothermia (Campbell et al., 2015), Cochrane Database of Systematic Reviews
Thermoregulation and Heat Balance (lecture slides, Leif Saager, MD, University of Michigan), Multicenter Perioperative Outcomes Group (MPOG)
Body temperature norms, MedlinePlus, US National Library of Medicine
IV Infiltration and Extravasation, St. Jude Children's Research Hospital, Together
Burns Sustained From Body Heating Devices: An Integrative Review (Kornhaber et al., Wounds, 2020), Wounds / HMP Global Learning Network
About Sepsis, Centers for Disease Control and Prevention
About HEATJAC. HEATJAC is a thermal architecture company founded by an anesthesiologist. We design patented garment systems that capture, conduct and broaden warmth across the body, and we publish this knowledge hub because the science of staying warm should be public. HEATJAC products are not medical devices and are not intended to diagnose, treat, cure or prevent any disease.