Myth Busting Monday: Should You Put Heat on a Fresh Sprain?
Written by Stephanie Austin, Owner and Lead Trainer, Prima Cura Training | Last reviewed: October 2026 | Next review: October 2027
No. Heat opens up the blood vessels around the injury, and a fresh sprain is already bleeding and swelling into the tissue, so warmth in the first few days makes the swelling and the bruising worse rather than better. NHS advice is to avoid heat, alcohol and massage for the first couple of days.
| MYTH | “Heat helps a fresh sprain.” A hot bath, a heat pack, a hot water bottle. It feels like it should help. |
| FACT | Heat makes the swelling and the bruising worse. Warmth widens blood vessels, and a fresh sprain is already bleeding into the tissue, so heat in the first few days adds to the swelling and the bruising rather than easing them. NHS advice is to avoid heat, alcohol and massage for the first couple of days. Cool it early, keep the heat for later, and if it is no better after two weeks, get it looked at again. |
My partner went over on his ankle. Somebody told him to put heat on it, so he did, and by the time he got home, he was in a serious amount of pain.
I got an ice pack on it. The swelling came down a bit but not by much.
A week later he was still in pain, still swollen, and the bruising had gone spectacular. He kept icing it. Another week later, his foot was going black, so he went to the doctor, who examined it, said it was a bad sprain and told him to carry on with the ice.
Another week. No better. I finally talked him into A&E, which he did not want to do, because by then he had been walking around on it for the best part of three weeks and had convinced himself it was just a bad sprain that was taking its time.
It was broken.
Two things came out of that, and they’re the two things this post is about. Heat at the start did him no favours at all. And nobody- him, me, or a doctor with his hands on the ankle- could tell it was a fracture without an X-ray.
Why does heat make a fresh sprain worse?
Because warmth widens blood vessels, and widened blood vessels in a freshly injured joint mean more blood arriving somewhere that is already leaking.
A sprain is torn or overstretched ligament. Small blood vessels tear with it, which is where the swelling and the bruising come from. Warm the area up in the first couple of days and you increase the flow into tissue that cannot hold it, so you get more swelling, more bruising, more pressure and more pain.
NHS guidance for the first two to three days is explicit about what to avoid: “heat (such as hot baths and heat packs), alcohol and massages for the first couple of days”.
The Northern Care Alliance NHS Foundation Trust spells out the reason in one line: “Hot baths, saunas and heat packs can increase bleeding/swelling.” The same leaflet puts alcohol and massage in the same bracket, for the same reason.
So a hot bath to relax after you’ve hurt yourself, a heat pack on the shelf that somebody swears by, a deep massage to “work it out”. All three are doing the same unhelpful thing.
Is ice definitely the right answer, then?
Here’s where I’ll be straight with you, because the advice has genuinely moved and most sprain articles won’t tell you that.
NHS public guidance still says to use ice. Apply an ice pack, or a bag of frozen peas, wrapped in a tea towel, for up to 20 minutes every two to three hours during the first two to three days. Never put ice straight onto skin, because it causes cold burns.
But physiotherapy practice has become more cautious about it. The PEACE and LOVE framework, used in NHS soft tissue injury guidance, covers the first 72 hours with Protection, Elevation, Avoid anti-inflammatories, Compression and Education, and it puts ice in the same bracket as ibuprofen: “Avoid taking anti-inflammatory medications such as ibuprofen and icing the injury as they can reduce tissue healing in the early stages.” From day four it switches to Load, Optimism, Vascularisation and Exercise, where increasing blood flow becomes the point rather than the problem.
So the honest position is this. Ice is for comfort and for keeping swelling manageable, not the thing that mends the ligament, and the NHS advice to use it sensibly is still perfectly reasonable to follow. What both camps agree on completely is the other half: nothing warm goes near it in the first few days.
That’s what makes this myth worth its own post. There’s a real debate about the cold. There’s no debate at all about the heat.
How do you tell a sprain from a break?
You don’t. Not from the outside, and that’s not a failure of attention.
Look at what the NHS lists as the symptoms of a broken bone: painful, swollen, bruised, difficult to move, and it may change colour, change shape or feel numb. Now look at a sprain. Painful, swollen, bruised, difficult to move. The lists overlap almost completely, and the two or three signs that do point clearly at a fracture, an odd angle, a bone through the skin, numbness, are the obvious ones that were never going to be missed anyway.
The NHS page on a broken ankle says the quiet part out loud twice over. “You’ll usually have an X-ray to check if your ankle is broken and see how bad the break is.” And then, plainly: “Do not worry if you’re not sure if your ankle is broken. Get it checked by a doctor.”
That’s the whole answer. An X-ray is what settles it. Everything before the X-ray is an educated guess, including the one a clinician makes with the joint in their hands, which is exactly what happened to my partner.
But surely you can’t walk on a broken ankle?
You can, and plenty of people do, for weeks.
Whether somebody can put weight on a limb is useful information, which is why “you cannot put weight on it” is on the NHS list of reasons to call 111. It just doesn’t work in reverse. Walking on it is not proof that nothing is broken, any more than wiggling your toes proves your spine is fine, which is the myth we covered in Can Someone Move Their Toes and Still Have a Spinal Injury?
Some fractures are stable enough to hobble on. Add the fact that people badly want it to be nothing, and you get three weeks of limping around on a broken bone while everybody tells each other it’s just a bad sprain.
When should you stop treating it yourself?
This is the part most people get wrong, and it is not really about the first hour. It’s about what you do on day ten.
Go to A&E, or call 999 if you cannot get there safely, if you heard a crack at the time, if the injured part has changed shape or is at an odd angle, if a bone is sticking out, if there’s a bad wound, or if the limb has gone numb, changed colour or feels cold. Those are the NHS thresholds and they need seeing straight away.
Call 111 if the pain is severe or getting worse, if there’s a large amount of swelling or bruising or it’s getting worse, if the person cannot put weight on it, or if there are signs of infection such as a high temperature or chills.
See a GP or a physiotherapist if the pain is getting worse rather than better after two weeks, or if you’re still not back to normal after six weeks.
And here’s the one that catches people out, including mine. Not getting better is itself a reason to go back. Not a reason to wait another week and see. Most sprains and strains feel better within about two weeks, so an injury that is no better after two weeks has stopped behaving like a simple sprain, whatever anybody called it the first time.
When is heat actually useful?
Later, and for a different job.
Once the acute phase has passed and the swelling has settled, warmth helps with stiffness and with the muscle tension that builds up around an injury while you’re guarding it. That’s the stage where a warm bath genuinely earns its place, and it lines up with the second half of PEACE and LOVE, where getting blood moving through the area becomes the aim.
The rule that’s worth remembering is about timing rather than about heat being good or bad. Cold at the start, for the swelling. Warmth later, for the stiffness. Getting them the wrong way round is what does the damage, and my partner managed it in the first hour.
Our longer piece on sprains and strains goes through the full recovery picture, including how long each grade of injury actually takes.
Frequently asked questions
Should you put heat on a sprained ankle?
Not in the first two to three days. NHS advice is to avoid heat, including hot baths and heat packs, along with alcohol and massage, for the first couple of days after a sprain, because heat increases blood flow to the injured area and can make bleeding, swelling and bruising worse. Heat is useful later, once the swelling has settled, for stiffness.
How long should you keep an ice pack on a sprain?
Up to 20 minutes at a time, every two to three hours, for the first two to three days, always wrapped in a tea towel or thin cloth rather than applied directly to the skin. Some NHS physiotherapy guidance now advises against routine icing of soft tissue injuries, so use it for comfort and swelling rather than expecting it to speed up healing.
How can you tell if it is a sprain or a break?
You usually cannot tell without an X-ray. The NHS lists pain, swelling, bruising, difficulty moving and sometimes a change in colour as symptoms of a broken bone, and those are the same things a bad sprain produces. NHS advice for a suspected broken ankle is that an X-ray is used to check whether it is broken, and that you should get it checked if you are not sure.
Can you walk on a broken ankle?
Yes. Some fractures are stable enough that a person can put weight on the limb and walk, which is why being able to walk does not rule out a break. Being unable to put weight on an injury is a reason to call 111, but being able to is not proof that nothing is fractured.
Training that covers the injuries people shrug off
Sprains and strains are the injuries that never feel like an emergency, which is exactly why they get handled on instinct and folklore instead of on what the guidance actually says. A first aider who knows the first two to three days, and knows the thresholds for sending somebody on, saves a lot of avoidable pain.
Emergency First Aid at Work (EFAW) is the one most workplaces need for a designated first aider, and higher risk sites usually need the three day First Aid at Work qualification instead. Schools should look at Emergency First Aid for Schools, and anyone working with young children needs Emergency Paediatric First Aid or the two day Paediatric and Early Years First Aid for Ofsted compliance. For a small team who just want the practical basics, Basic First Aid covers it.
If most of your incidents are slips, trips and falls, Fall Prevention Awareness and Moving and Positioning of People sit well alongside first aid training.
Not sure what your organisation needs? Our Workplace First Aid UK Guide walks through needs assessments and qualification levels. Give us a call on 0333 999 8783 or drop us a message and we’ll help you work it out.
THE VERDICT: BUSTED
Keep it cool for the first few days, keep the heat for later, and if it is no better after two weeks, stop calling it a sprain and go and get a picture of it.
This article is provided for general information and awareness only and reflects NHS guidance applying in England as at October 2026. It does not constitute medical advice, and it is not a substitute for accredited, hands-on first aid training. Guidance can change, and how it applies depends on the individual and the circumstances of the injury. A sprain and a fracture cannot reliably be told apart without imaging, so any injury that is severe, misshapen, numb or not improving needs proper medical assessment. In an emergency, always call 999.
