According to a study published in the European Heart Journal, pink noise appears to stimulate deep sleep stages, promoting not only proper rest but also improved heart function. Let’s see how.
What is pink noise?
First and foremost, one might wonder what exactly is pink noise. These are sounds in which the low frequency components are stronger than the others. Not to be confused with white noise (the one many parents are familiar with because it often helps calm very young children), in which the various frequencies all have more or less the same power.
Examples of pink noise can be the frequencies produced by a downpour, the rustling of leaves when the wind blows or the noise produced by a waterfall. On the other hand, an example of white noise is that made by a vacuum cleaner or fan.
How do these appear to help the heart?
The study in question involved 18 healthy men between the ages of 30 and 57, who were asked to spend three nights (one week apart) under observation in a research laboratory. During two of the three nights the participants were exposed to pink noise at regular intervals. One night, on the other hand, served as a negative control, i.e. the participants were monitored but were not exposed to any noise while sleeping.
Among the parameters monitored werebrain activity, blood pressure andcardiac activity. During stimulation we clearly see an increase in the slow waves [of sleep, those occurring when the subject is going through a deep resting phase, ed] as well as a response from the cardiovascular system reminiscent of the heart pulse’, explains Stephanie Huwiler, researcher at the ETH Zurich.
In essence, the research authors explain, the results indicate that fostering deep sleep phases through stimulation with pink noises appears to make the heart, and in particular the left ventricle, more efficient at pumping blood to the whole body. This benefits not only organs and tissues, which receive more oxygen, but also the cardiovascular system itself.
Limitations of the study
It is important to emphasise that the study involved a rather small sample of participants and, above all, did not involve women. As Caroline Lustenberger, who led the study, explains, this was a conscious choice, since in women the hormonal fluctuation due to the menstrual cycle could have affected the observations collected over a total of three weeks.
One of the future goals of the research team is indeed to broaden the study to include the female sex, so that any gender differences, which are becoming increasingly evident in many areas of medicine, can be analyzed.