Heat or Ice for Back Pain? What's the best approach?
There can be mixed advice available to us all when it comes to back pain. The reasons for the conflicting advice are complex. Practitioners may not be up to date with advice or evidence, and are often thinking things through a lens of 1) What they learned many years ago at school or 2) What they have always done.
A different strategy is to search for high quality evidence where interventions are pitted against one another to determine if either 1) works or 2) is superior.
High quality evidence is often published by reputable resources, such as Cochrane Review, or Journal Articles with well respected authors and editors. Another heuristic is to look for terms such as "systematic review" and "meta-analysis". These articles are considered the top of the evidence based hierarchy and have larger sample sizes included; they are taking multiple small randomised trials, and combining the results to get a better understanding of the likelihood of a successful or unsuccessful outcome when observed with big numbers. Statistical effects can sometimes become more obvious with larger sample sizes.
When it comes to pain management with heat or cold, there are several things to consider. Pain is complex, and past experiences will play a role. If ice or heat have worked for you in the past, it's often ok to stick with whatever works for you. So there is no need to feel that one is right or wrong.
However, guidelines recommend heat from a hot water bottle or heat wrap. The evidence seems to be based on low level evidence. This systematic review found heat and topical rubs with capsicum help with low back pain. And this highly respected Cochrane Review found that heat was also beneficial; however, it was based on low quality evidence and it was not clear if it was equally effective to use ice.
In summary, both heat and ice are probably effective for helping with back pain. It's not clear whether one is more effective than the other. So, if you have had good experience in the past, stick with it, it can only help and is unlikely to cause harm. If you are looking for some guidance in the first instance of a back ache, try heat, since it feels comforting for most people and since guidelines recommend it.
You can be reasured that the rational for how they might work is based primarily on analgesia (pain reduction) rather than actually changing inflammation or promoting/controlling vasodilation, which are often times the over-complicated clinical reasoning. To use a line from this randomised controlled trial, "Choice of heat or cold therapy should be based on patient and practitioner preferences and availability."
Abdel Shaheed C, Maher CG, Williams KA, McLachlan AJ. Interventions available over the counter and advice for acute low back pain: systematic review and meta-analysis. J Pain. 2014 Jan;15(1):2-15. doi: 10.1016/j.jpain.2013.09.016. Epub 2013 Oct 14. PMID: 24373568.
French SD, Cameron M, Walker BF, Reggars JW, Esterman AJ. A Cochrane review of superficial heat or cold for low back pain. Spine (Phila Pa 1976). 2006 Apr 20;31(9):998-1006. doi: 10.1097/01.brs.0000214881.10814.64. PMID: 16641776.
Garra G, Singer AJ, Leno R, Taira BR, Gupta N, Mathaikutty B, Thode HJ. Heat or cold packs for neck and back strain: a randomized controlled trial of efficacy. Acad Emerg Med. 2010 May;17(5):484-9. doi: 10.1111/j.1553-2712.2010.00735.x. PMID: 20536800.