By Emma Young
Do you listen to quiet music to help you wind down before sleep? If you do, you’re following the advice of all kinds of organisations, including the US National Institutes of Health and the National Sleep Foundation. However, this advice could be counter-productive, according to a new study by Michael K. Scullin and colleagues at Baylor University. The work, published in Psychological Medicine, found that bedtime music was associated with more sleep disruptions — and that instrumental music is even worse than music with lyrics.
In the first study, 199 online participants living in the US reported on their sleep quality and music listening frequency and timing, as well as their beliefs about how this affected their sleep. Almost all — 87% — believed that music improves sleep, or at least does not disrupt it. However, the team found that more overall time spent listening to music was associated with poorer sleep and daytime sleepiness. Just over three quarters of the participants also reported experiencing frequent “earworms” — having a song or tune “stuck” and replaying in their minds. A quarter reported experiencing these during the night at least once per week, and these people were (unsurprisingly) six times as likely to report poor sleep quality. The team’s analysis suggested that listening specifically to instrumental music near bedtime was linked to more sleep-related earworms and poorer sleep quality.
The team then ran an experimental study on 48 young adults. After arriving at the sleep lab at 8.45pm, participants went to a quiet, dimly lit bedroom, where they completed a host of questionnaires that included measures of stress, sleep quality and daytime sleepiness. They also had electrodes applied, ready for the night-time polysomnography (which recorded their brain wave activity, as well as heart rate and breathing), and reported on how relaxed, nervous, energetic, sleepy and stressed they felt.
At 10pm, they were given some “downtime”, with quiet music playing. Half were randomised to hear three songs: “Don’t Stop Believin’’’ by Journey, “Call Me Maybe” by Carly Rae Jepsen and “Shake It Off” by Taylor Swift, while the other half heard instrumental-only versions of these same songs. (The team chose these songs because they are known to cause earworms and were likely to be very familiar to the participants.)
Participants reported decreases in stress and nervousness and increased relaxation after listening to either set of songs, and also showed decreases in blood pressure. So — as earlier studies have also suggested — quiet music at bedtime was indeed relaxing at the time. However, a quarter of the participants woke from sleep with an earworm, and the polysomnography data showed that instrumental versions of the songs were more likely to trigger these awakenings as well as to cause other sleep disruptions, such as shifts from deeper sleep to lighter sleep. Taken together, the findings represent “causal evidence for bedtime instrumental music affecting sleep quality via inducing earworms,” the team writes.
The EEG data showed that the participants who woke up with an earworm had significantly greater “frontal slow oscillations” — a classic signature of memory consolidation during sleep. Earworm-associated slow oscillations were also seen in the auditory cortex, which processes sounds. Earworm awakenings seem, then, to result from the reactivation of melodies heard during the day during sleep, as part of the memory consolidation process. The team’s overall data suggests that this is more likely to happen when the melodies are heard around bedtime, and are instrumental.
Why instrumental-only songs should have a bigger impact than music with lyrics isn’t clear. The three songs used in this study were chosen because they were likely to be familiar. Hearing them without the lyrics might have prompted the participant’s brains to try to add the words, which might have made earworms more likely. If this is the case, all instrumental music may not have the same effect. However, the data from the first study is consistent with the idea that instrumental music generally is more of a problem.
This work has practical implications, of course. “Just because music listening is enjoyable does not mean that more music is always better for health outcomes,” the team writes.
And for anyone who finds themselves struggling with earworms at night, the researchers have a few recommendations: limit how much music you listen to during the day, and avoid listening to music before bed. Instead, perhaps spend 5-10 minutes writing out a to-do list for the next day, as earlier work involving Scullin has found that this helps people to get to sleep. If you do struggle with sleep, you might also want to look into digital interventions, or even a rocking bed.