Turn Down the Volume to Turn Down the Pain

Source: Thomas Breher/Pixabay

Whenever I head for the gym, I always make sure to bring my music with me. (I’ve been known to turn around mid-trip, in fact, on those rare occasions when I realize I've left my earbuds at home.) And when I work out to music, I always play it loud, believing—or at least hoping—that cranking up the volume will help to mute the pain of my treadmill runs, bench presses, and squats. According to an article just published in Science, however, I may be going about my auditory pain-reduction practice the wrong way.

Music Can Ease the Pain

It's been known for some time that listening to music can reduce the amount of pain people feel when undergoing a painful experience. Since a group of dentists found in 1960 that playing music for their patients during dental procedures reduced their perceived level of pain, numerous studies have confirmed that listening to music can have an analgesic effect, but the neural mechanisms behind this effect have largely remained a mystery. An international team of scientists recently conducted a study with mice in an attempt to solve this mystery.

The researchers injected the mice’s paws with a solution that caused inflammation and then, while exposing them to music as well as to a white noise source, prodded their paws with thin filaments and observed their response to the painful stimulus (e.g., licking, flinching). As in previous studies, exposure to music reduced the mice’s sensitivity to pain.

Using viral tracing, microendoscopic calcium imaging, and multielectrode recordings to trace connections between brain regions, the researchers identified a pathway from the auditory cortex to the thalamus (the auditory cortex receives and processes sound information and the thalamus relays sensory signals, including pain, from the body). In the presence of music, neuronal activity at the receiving end of this pathway was reduced, suggesting a reduction of pain processing in the thalamus.

Volume Makes the Difference

In addition to identifying a neural mechanism involved in the analgesic effect of music, the study also produced an unexpected discovery involving the volume at which the music was played. The music to which the mice were exposed was of two types, "pleasant" and "unpleasant" (a pleasant piece of classical music and an unpleasant rearrangement of the same piece) at different volume levels. Along with the music, the mice were exposed to white noise, also at differing volume levels.

Surprisingly, the type of music to which the mice were exposed, whether pleasant or otherwise, made no difference in the mice’s response. Nor did the substitution of white noise for music. The mice's response to the pain stimulus was identical in the presence of all three types of sound. The intensity at which the music and white noise were played, however, did make a difference in the mice's response to the pain stimulus. Whether the mice were exposed to pleasant music, unpleasant music, or just white noise, only the sounds that were played at a lower volume—just slightly above background noise level—produced the pain-numbing effect. When the music and white noise were played at a higher volume, the mice’s response to the painful stimulus was no different than it was with no music at all.

While humans and mice are obviously very different, this study involving mice suggests some intriguing possibilities for human health care, especially in the field of pain management. If the results turn out to be transferrable to humans, they could help researchers develop safer alternatives to opioids for treating pain.

Whatever its long-term implications for health care may be, the study has made me rethink my own personal pain management strategy for working out. The next time I hit the gym, I’m going to try pumping down the volume, instead of pumping it up, while I lift weights or run on the treadmill.