Sunburn continues to colour many of our experiences of the summer. Even as it draws to a close we can still get caught out.
We are all familiar with the effects, and the warnings, but what’s going on in your nervous system is more interesting than you may think. The term itself is slightly misleading. When we feel our skin burning after we’ve been in the sun for too long, our brain is actually being fooled.
There are several kinds of nerve that connect our skin to our brain, including touch sensors, but only one communicates signals from heat receptors. This information is perceived by the brain as a burning pain to encourage us to pull our hand out of the fire. In reality, the damage done by ultraviolet radiation from the sun causes damage even when the skin isn’t hot.
Similarly, eating chilli chemically activates the heat detectors when there’s no significant heat involved. So we get a ‘burning’ taste in our mouth or even on our skin because our brain can’t tell what set off the nervous impulses.
In the case of sunburn, since the damage is already done, the pain doesn’t really serve a purpose.
Dr Daniel Glaser is director of Science Gallery at King’s College London
