Reach for the frozen peas or the hot water bottle? It is one of the first questions people ask after twisting an ankle, waking with a stiff neck or overdoing it in the garden. The short answer is that cold and heat do different jobs, and knowing which to use, and when, makes both far more useful.
When to use cold
Cold is for new injuries and flare-ups where there is swelling, warmth or sharp pain. Cooling the area narrows the small blood vessels, which helps limit swelling, and it numbs the nerve endings, which eases pain. Typical uses include:
- A sprained ankle, wrist or knee in the first day or two.
- A pulled muscle or a knock that is bruising and swelling.
- A joint that has flared up and feels hot after activity.
- Sore shins or heels after a hard training session.
When to use heat
Heat is for stiffness, tightness and longer-standing aches without swelling. Warmth relaxes muscles, increases blood flow and makes stiff tissue easier to move. Typical uses include:
- A stiff lower back or neck in the morning.
- Tight shoulders after a day at the desk.
- Muscles that feel knotted or tense rather than injured.
- Joint stiffness in cold weather.
- Warming up a stiff knee or shoulder before gentle exercise.
A simple rule of thumb
Swollen, hot or newly injured: cold. Stiff, tight or chronically achy: heat. If you are unsure, cold is the safer first choice in the first 48 hours after an injury, and heat is generally more comfortable after that if swelling has settled.
How to apply cold safely
- Wrap the ice pack, frozen peas or gel pack in a tea towel. Never apply ice directly to the skin.
- Apply for 10 to 15 minutes, then remove for at least an hour before repeating.
- Check the skin regularly. Stop if it goes white, blotchy or numb.
- Do not fall asleep with a cold pack in place.
How to apply heat safely
- Use a heat wrap, wheat bag or hot water bottle in a cover. It should feel comfortably warm, not hot.
- Apply for 15 to 20 minutes at a time.
- Never use heat on an area that is swollen, bruised, hot to touch or numb.
- Avoid lying on a heat source and do not use heat over broken skin.
Combining with a support
Cold or heat therapy and a support work well together. Cool a new sprain first, then apply a compression support between icing sessions to control swelling. For a stiff, achy joint, warm it gently before activity and wear a sleeve for the activity itself to maintain warmth. Reusable gel packs that can be chilled or warmed make it easy to switch between the two.
Who should take extra care
People with diabetes, poor circulation, reduced skin sensation, or conditions affecting the nerves should take advice before using hot or cold therapy, as they may not feel when the skin is being damaged. Check with a pharmacist or GP if unsure.
When to get advice
Seek medical help if you cannot put weight on a limb, a joint looks deformed, there is severe or rapidly increasing swelling, numbness or tingling, or if pain has not started to settle after a few days of sensible self-care.
Frequently asked questions
Can I alternate hot and cold?
Contrast therapy is sometimes used once the acute phase has passed. Keep sessions short and finish on cold if there is any swelling.
How long after an injury should I keep icing?
Typically the first two to three days, or for as long as swelling and heat persist. After that, switch to gentle movement and warmth if it feels better.
Is a heat rub the same as a heat pack?
Heat rubs and patches create a warming sensation on the skin rather than deeper warmth. They can be soothing, but follow the product instructions carefully.
Explore first aid and recovery
Browse the Venollo range and read our guides to building a home first aid kit and elastic bandages.
This article is general information and is not a substitute for medical advice. If you have an injury, a health condition or ongoing symptoms, please speak to a qualified healthcare professional.
