One type of noise especially improves sleep and memory

White noise has been getting way too much credit for helping people sleep. Turns out another kind of noise delivers far deeper slumber — and improves memory.

The authors of a new report published in the Annals of Clinical and Translational Neurology discovered an effective way to boost both cognitive function and sleep, based on the way our brain processes sounds when we’re resting.

Not only do gentle sounds played during specific sleep times improve memory, but they may also reverse some of the consequences associated with insomnia and dementia-related illness among older populations.

In fact, older participants enjoyed the most profound benefits compared to the rest of the cohorts involved in the analysis.

The authors — researchers from Northwestern University — found a strong correlation between the enhancement of deep sleep induced by sound and regions of the brain responsible for memory retention.

Why pink noise may boost your memory

After recruiting nine adults who had all previously reported mild cognitive impairment, the authors treated them with a sound simulation while they were in third-wave sleep. Every night before bed, the participants performed memory tests.

The sound simulation employed in the new study utilized intermittent pulses of pink noise, which is defined as random noise having equal energy per octave and more low-frequency components than white noise. The sounds naturally occur in nature all the time via things like the rustling of leaves, wind, and rainfall. These seemed to consistently induce deeper sleep for the study pool.

The researchers determined that the participants who had the biggest increases in their slow-wave activity after the sound stimulation could remember more words from the memory tests administered the day before. So it seems that the pink noise sound simulation improved cognitive function by inducing deeper waves of sleep for the participants.

This isn’t the first time that research literature has revealed this kind of effect. In a 2017 study conducted by the Frontiers in Human Neuroscience, the authors also found a positive link between pink noise and deep sleep.

You can find pink noise for sleep on your computer or smartphone through streaming services like Spotify, Apple, and YouTube. There are also apps that offer recordings of various noise “colors.”

“The best way to use pink noise depends on your preferences. For example, you may feel more comfortable with ear buds instead of headphones. Others might prefer headphones or playing pink noise on a computer,” Healthline reports.

Sleep and cognitive function

Sleep has been shown to support memory retention by clearing out brain toxins linked to the development of dementia. Science suspects that cerebrospinal fluid (CSF) may flush rid of brain waste when we’re resting.

Previously conducted research literature has established a strong relationship between slow-wave sleep specifically and reduced disease incidence.

In another study, researchers recruited participants who were in their 50s and 60s and found that getting six hours of sleep or less put them at a dramatically greater risk for developing dementia later in life. More specifically, those who got less than adequate amounts of sleep each night (defined as 7 hours or more) were 30% more likely to be diagnosed with dementia.

“The findings suggest that short sleep duration during midlife could increase the risk of developing dementia later in life. More research is needed to confirm this connection and understand the underlying reasons,” the authors wrote.