Every clinician has no doubt lost count of how many times they’ve been asked this in practice. Some patients have been told by a previous clinician that they should use heat, never ice… Others, the opposite.

So what does the evidence say? Let’s take a dive into the research.

Ice slows things down, while heat speeds them up - but which is better for healing?

We are looking at studies for non-specific mechanical pain of spinal origin. This means any spinal pain that isn’t a fracture, nerve pain or something worse – basically the bread-and-butter of what chiropractors see in their offices. This won’t include things like ankle sprains with lots of swelling, for reasons that will become clear.

First let’s look at the effects of both:

Cold therapy slows things down and heat speeds things up. That’s a bit of an oversimplification, but works just fine for our purposes. We think heat speeds blood flow and gets more nutrients and oxygen to the site of injury, promoting healing. Ice restricts the flow of these things and can reduce inflammation. So which is best?

Inflammation & healing

You may be thinking “surely we want the quickest healing possible, so heat is always the answer”, or perhaps “well I know inflammation is bad, so surely we want the least inflammation possible, so I’ll use ice". I’m about to blow your mind.

Healing is inflammation. Inflammation is healing. Inflammation is the name we give to the combination of processes that happen at the cellular level when tissues are healing. Why would we want to stop healing? Surely some healing is good, and more is better?

Think of it this way. A sledgehammer would crack a walnut very quickly and effectively,. But the end product would be less desirable. That’s why we still (mostly) recommend ice for acute injuries like ankle sprains. The body is rushing lots of swelling and healing factors into the injury, too quickly for the area to handle. Ice applied immediately after injury helps to put the brakes on this process, which can reduce healing times.

This is not what is happening with the kinds of spinal issues chiropractors mostly see in practice though. Despite what you may have been told, you almost certainly haven’t torn a muscle or ligament, so the question of inflammation in mechanical low back pain is not that relevant.

What the evidence says

If you are considering ice or heat for what you consider a muscular problem, having looked at the diagram above you may notice that heat increases elasticity, whereas ices reduces elasticity… But also reduces muscle spasm. This can be confusing. Ultimately the evidence suggests that for pain or function, the headline is that there is no discernible difference in outcomes between the use of ice or heat.

This study found that pain relief for low back DOMS (delayed onset muscle soreness) was 138% greater with heat compared to cold at 24 hours post-exercise, but found no differences in physical function or disability.

This study compared the painkilling effects of 30 minutes of heat or cold applied to patients presenting at an emergency department. The researchers found no significant differences in outcomes

A Cochrane review found that any evidence for differences in heat and cold therapy was inconclusive.

How do we choose between heat and ice?

There is no evidence to recommend heat over ice or vice versa for low back pain. However individual preferences DO play a part in outcomes, so if you have a preference for one or the other, pick that one. Or pick both. The theme that will reappear, time and again, is that movement is medicine and motion is lotion. So if ice, heat, or some combination of the two help to get your low back moving again, jump in that ice bath or sauna, but for the love of all things spinal get yourself active again. If you need any more reasons see our previous post on why exercise is a non-negotiable.