Ice or Heat for an Injury? A Physio’s Guide

Key Takeaways

• For a new sprain, strain or knock, avoid heat for the first 72 hours, because heat can increase bleeding and swelling at the injury.
• Ice can ease pain straight after an injury, but Healthify’s current guidance is to use it only in the first few hours and for no longer than 10 to 15 minutes at a time.
• Heat is better suited to stiffness and muscle tension, such as an ongoing stiff back or tight neck, rather than a fresh injury with swelling.
• Never put ice or a heat pack directly on bare skin, and avoid ice if you have problems with circulation or sensation.
• Ice and heat can ease pain but don’t fix the cause; if pain or swelling hasn’t improved within two days, get the injury checked.

You roll your ankle at netball, tweak your back lifting a box or wake up with a stiff neck. The first question is often the same: should I use ice or heat for an injury like this?

For a fresh injury, the short answer is: no heat for the first few days, and ice only briefly, if at all. Heat is for stiffness. The advice on ice has changed in recent years, and many people are still following the old rules. This guide explains when to use each, how to do it safely and when it’s time to see a physio.

Should I Use Ice or Heat for an Injury?

For a new injury that is painful, swollen or bruised, such as a sprained ankle or a pulled muscle, skip the heat. Ice may help with pain in the first few hours. For stiffness or muscle tension that has built up over time, with no new swelling, heat is usually the better choice.

Situation	Better choice
New sprain, strain or knock (first few hours)	Ice, briefly, for pain relief
New injury (first 72 hours)	No heat
Stiff, tight muscles with no recent injury	Heat
Ongoing neck or back stiffness	Heat
Not sure what the injury is	No heat, and get it checked

When to Use Ice

Ice can be useful straight after a new soft tissue injury, such as a sprained ankle or a calf strain, mainly to ease pain. Healthify, New Zealand’s health information site, says that if you only use ice in the first few hours and for no longer than 10 to 15 minutes at a time, it may help with pain and swelling caused by bleeding from damaged blood vessels.

How Long Should You Ice an Injury?

Keep each session to 10 to 15 minutes, and only use ice in the first few hours after the injury. If your injury is more than mild, ask your physio or GP for advice on whether ice suits your situation.

How to Ice an Injury Safely

• Wrap it. Never put ice directly on bare skin. Wrap the ice pack, or a bag of frozen vegetables, in a towel or light cloth.
• Keep it short. 10 to 15 minutes is enough. Longer is not better.
• Stop if it hurts. If the cold itself becomes painful, take it off.
• Avoid ice if you have circulation or sensation problems. Healthify notes that ice is not recommended for people with problems with circulation or sensation.

What Else Helps in the First Few Days

Ice is only one small part of early injury care. Healthify’s guidance for the first two to three days also includes:

• Protect: keep weight off the injured part for the first few days, then move on from protection as pain improves
• Elevate: raise the injured limb above the level of your heart to help reduce swelling
• Compress: taping or a firm (not tight) bandage can help reduce bleeding and swelling; loosen it if your fingers or toes go numb or tingly

If you’ve had surgery, follow the advice from your surgeon or physio about cooling and swelling management, as this may differ.

When to Use Heat

Heat may help with stiffness and muscle tension rather than new injuries. Many people find warmth helps muscles relax and makes it easier to start moving a stiff area.

Situations where heat may help include:

• a stiff, achy lower back with no new injury
• neck pain and shoulder tension from long hours at a desk
• joint stiffness first thing in the morning
• loosening up a stiff area before gentle stretches or your home exercises

How to Use Heat Safely

• Use gentle warmth. A wheat bag, heat pack or warm (not hot) water bottle is enough.
• Wrap it. Put a towel or cover between the heat source and your skin.
• Check your skin regularly, and take the heat off if it feels too hot.
• Don’t fall asleep with a heat pack on. Falling asleep with a heat pack on can cause burns.
• Avoid heat on any area with swelling, bruising or broken skin.

Why You Should Avoid Heat on a New Injury

Avoid heat for the first 72 hours after a sprain or strain, because it can increase bleeding and swelling at the injury.

Healthify advises avoiding HARMS straight after an injury: heat, alcohol, running (or any exercise), massage and smoking. It specifically names hot packs and baths. KidsHealth NZ gives similar advice for children, saying to avoid heat packs, hot rubs and massaging the area in the 72 hours after an injury.

A common mistake is jumping into a hot shower or spa straight after a sports injury because it feels soothing. Hold off on the heat for a few days, until any swelling has settled.

Ice or Heat for Back Pain?

For back pain, it depends on how the pain started.

• Sudden pain after a specific incident, such as lifting or a fall: avoid heat for the first few days. A short spell of ice in the first few hours may ease pain.
• Stiffness and aching that have built up over time, or a back that feels tight first thing in the morning: gentle heat often feels better and can make it easier to start moving.

If your back pain comes with numbness, pins and needles or pain travelling down your leg, get it checked rather than self-treating. If you have numbness around your groin or buttocks, or new problems controlling your bladder or bowel, seek urgent medical help.

Cold Compression Therapy for Recovery at Home

Cold compression therapy gives steadier cooling than a standard ice pack, and it’s mainly used to manage swelling after surgery. A regular ice pack warms up quickly and needs constant refreezing, which makes consistent cooling hard to manage at home.

We offer cold compression therapy rental using the Cryo Unit from Victor Sports. It combines steady cooling with controlled compression and stays securely in place. Units are available for knees and shoulders at $195 per fortnight. Your physio can advise whether it suits your recovery and how to use it alongside your rehabilitation exercises.

When to See a Physio

See a physio if your injury isn’t improving within two days, or if it’s stopping you from moving normally. Book an assessment if:

• pain or swelling hasn’t improved within two days
• you can’t put weight on the injured leg or use the injured arm normally
• the joint feels unstable or gives way
• pain keeps coming back with the same activity
• you have numbness, tingling or weakness

If you think you may have broken a bone, or the injury is severe, see a doctor or visit an urgent care clinic first.

You don’t need a GP referral to see a physio, unless your health insurer requires one. If your injury was caused by an accident, we can lodge an ACC claim for you at your first appointment. Find out what to expect at your first physio appointment.

Get Expert Advice on Your Injury

At Cairnhill Physiotherapy, we help Aucklanders recover from sprains, strains and sports injuries with one-on-one care and a clear plan. Our sports physiotherapy team will assess your injury, explain what’s going on, and show you how to manage it at home, including when to reach for ice or heat.

Book online or call 09 631 5991. We’re at 95 Mountain Road, Epsom, open Monday to Friday, 7am to 6pm, with free onsite parking.