Virtually every day in our clinic, we will have patients telling us that their back feels better of t’s warm outside or if they have had a hot bath, or traveled to a warmer climate.
This is a common report, which makes it hard to believe that people do not genuinely get better from such types of experiences.
Research shows that there is no empirical evidence to show that heat actually helps. However, what we commonly see with patients who describe heat as beneficial is that they are over 50 and have a history of recurrent back pain. In addition, people in this category often struggle with sustained positions such as bending, sweeping, gardening, etc. The problem is caused by a degenerative change in the lumbar spine.
One of the reasons why those tissues like the heat is because of a concept known as viscoelasticity, meaning that elasticity in the tissues improves as the tissue-temperature increases. Therefore, older tissues undergoing degenerative change benefit because they feel more elastic and mobile when heated. This phenomenon generally gives the perception that it is easier to move and that there is less motion restriction.
The other factor to bear in mind is that when joints feel stiff and sore, the muscles will tend to tense around those joints. This results in an increase in the perception of stiffness. The effective heat, in general, reduces the tension in muscles and hence reduces those layers of protective tension around a sensitive joint. These reasons make people feel that heat is beneficial for simple lower back pain.
If you have back pain with sciatica, and if you are in that older patient population, you may have a slight conflict by thinking that the heat will benefit the stiff joints but it only compounds the swelling caused by sciatica. This is because heat contributes more to the inflammatory response due to increased pressure on the nerve and is therefore not appropriate in such a situation.
If you are a younger spine and you have acute sciatica, there is no role for heat in soothing your pain. This may sound a little contra-intuitive because although the heat reduces and soothes the muscle tension, it only enhances the inflammatory reaction.
