Heat for lower back pain: how a hot water bottle can help

A stiff, aching lower back is one of the most common complaints there is. Many people instinctively reach for something warm, and with good reason. Here's what heat does for back pain, what research shows and how to use it.

Why warmth feels good on a sore back

• It loosens tight muscles. Back pain often comes with tense, stiff muscles. Heat helps them relax.
• It improves blood flow. Warm skin widens the blood vessels underneath, bringing more blood to the area.
• It calms the pain signal. Heat on the skin activates receptors that can dampen the way pain is signalled to your brain. (We explain how in this article.)

What research says

A Cochrane review, one of the most thorough types of medical research summary, looked at heat for lower back pain. It found moderate evidence that heat wrap therapy gives a small reduction in pain and stiffness in the short term for people with acute or sub-acute low back pain (pain that has lasted up to about three months). Adding gentle exercise to heat improved results further.

In short: heat is not a cure, but it can make an aching back noticeably more comfortable and help you keep moving, which is usually exactly what a sore back needs.

Keep moving, keep warm

For most everyday back pain, staying active helps recovery more than lying still. That's where a regular hot water bottle falls short: it only works while you lie on it. A hot water bottle in a belt keeps warmth on your lower back while you walk, work or do your stretches.

Melty was designed for period cramps on the belly, but you can simply turn the belt around so the bottle sits on your lower back. See how Melty works.

How to use heat for back pain

• Warm, not hot. Fill the bottle with hot, not boiling, water. It should feel pleasantly warm, never burning.
• Always use a cover. Never put a hot water bottle on bare skin.
• Don't lie on it. Lying on a filled hot water bottle puts pressure on it and can make it burst. A belt is safer than putting the bottle under your back in bed.
• Check your skin regularly and take a break if it gets red.
• Combine with movement. Gentle walking and stretching work well together with warmth.

When to see a doctor

See a doctor straight away if back pain comes with numbness or tingling in your legs, loss of bladder or bowel control, fever, unexplained weight loss, or if it follows a fall or accident. Also get checked if the pain is very severe or doesn't improve after a few weeks. Heat helps with everyday aches, not with underlying conditions.

In short

Heat can take the edge off lower back pain and help you stay active. Research supports a small, short-term benefit, especially when you combine warmth with movement. A wearable hot water bottle makes that combination easy.

Source: French SD, Cameron M, Walker BF, Reggars JW, Esterman AJ, Superficial heat or cold for low back pain, Cochrane Database of Systematic Reviews, 2006. This article is for general information and is not medical advice.