Heat or ice — and when each one helps

It is one of the most common questions we are asked, and the honest answer is that it matters less than most people expect. Neither heat nor ice changes how an injury heals. What they change is how comfortable you are while it does — and comfort is worth having, because it lets you keep moving.

What ice is good for

Cold reduces the sensation of pain in the short term. That makes it useful in the first day or two after an acute injury — a rolled ankle, a knock to the knee — when things are sharp and swollen. Fifteen minutes at a time, with a cloth between the ice and your skin, is plenty.

The older advice was to ice aggressively to stop swelling. Swelling is part of the healing response, so suppressing it completely is not the goal. Use ice for comfort, not as treatment.

What heat is good for

Heat helps muscles that feel tight, guarded or achy — the stiff lower back in the morning, the neck that seizes after a long drive. It is usually more useful than ice for pain that has been around a while.

The part that actually matters

Whichever you choose, the point is to make movement possible. An ankle that hurts less will bear weight sooner; a back that has loosened will bend more freely. The heat or ice is the doorway, not the room.

• Recent, sharp, swollen — try ice, briefly, for comfort.
• Stiff, achy, longer-standing — try heat before you move.
• Either way — follow it with the movement your physiotherapist has given you.

If you are using one of them several times a day for weeks and nothing is changing, that is the signal to get assessed rather than to buy a bigger heat pack.