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“Pink Noise” Improves Sleep

Insomnia affects nearly ten percent of Americans. A survey of more than seven thousand people found that 23% exhibited signs of insomnia and estimated that lack of sleep costs the country 63 billion dollars annually in lost productivity. Some preliminary studies have suggested that applying a gentle current to the brain might ameliorate this issue, but the idea has been understandably unpopular among potential patients.

In an effort to find another method to ameliorate insomnia, researchers conducted a study of of “pink noise,” a type of noise with a power spectrum that is inversely proportional to its frequency. It is called pink noise because visible light within this spectrum appears pink in color. In executing their study, the scientists had eleven volunteers spend two nights in their sleep lab, one while pink noise matched to their brain waves was played and one in silence. Before they went to sleep, they were showed pairs of words and asked to memorize them. The volunteers were also hooked up to EEGs so that their brains could be monitored while they slept.

During the night with pink noise playing, the researchers recorded prolonged deep sleep and increased size of the  wavelengths in the volunteers’ brains. These slow brain waves are connected with memory retention and “information processing,” which was reflected in the researchers results. The volunteer sleepers performed better in the memory exercise when the pink noise had played as they slept.

The scientists involved in this study emphasize that the pink noise was matched to the brain waves of the patients, and that further research and development could lead to tools to improve sleep and even enhance brain activity while awake. Entitled Auditory Closed-Loop Stimulation of the Sleep Slow Oscillation Enhances Memory, the study was published in Neuron.

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  1. rmelman

    I found an article that is about different types of noise-canceling and noise producing devices. It says that although white noise devices help the costumer to sleep, pink noise might be better.
    If you’re interested, maybe you can buy a pink noise machine!

  2. Thans

    I too enjoyed this post. Upon reading this I was like, “huh isnt that what white noise is?” but no I was wrong. I did some research and found out that pink noise is actually a slightly different more subtle thing. It is a type of sound wherein, “every octave carries the same power, or a perfectly consistent frequency,” according to doctor Jue Zhang of Peking University. I find it interesting to think that in a society where sleep is such a precious commodity there are such simple ways to drastically increase its quality. Anyhow here is the link to the article I found:

  3. danasaurus

    This is a very interesting post! It is amazing to think that producing a noise that has a power spectrum that is inversely proportional to its frequency can help us sleep. There are actually many videos on youtube of continuous “pink noise” that you can play while sleeping, here is a link:
    Also I read an article which talked about how sounds play important roles in our sleep patterns, even if we are not consciously listening this article adds some detail to how pink noise works:

  4. karbonkim

    I really enjoyed this post. I found it interesting to learn about the benefits of pink noise. On another website, I read about how to produce pink noise within your own home.
    It said to have a steady, uninturrupted sound like a fan or something that imitates rainfall or wind. I thought this was a helpful tip to allow one to have a better sleep. Here’s the link:

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