Chances are, you’ve heard of white noise. It’s often used to mask other sounds, or can be associated with the buzz from radios or TVs when they’re not catching the appropriate signal.
But where does its lesser-known cousin “pink noise” come into play, and what does it have to do with memory and sleep among older adults?
That’s what researchers explored in a new study published in Frontiers in Human Neuroscience. The findings suggest that older adults can achieve deeper sleep and stronger memories when they listen to the soothing tones of pink noise, which consist of a mix of high and low frequencies sounding more even and natural than white noise.
Deep sleep is crucial for maintaining cognitive function—how many of us have trouble remembering things after a fitful night of sleep?—but older people have a greater risk of memory impairment and typically experience less slow-wave sleep. Since prior studies have shown that playing pink noise during sleep improves the memory of younger adults, senior author Dr. Phyllis Zee, professor of neurology of Northwestern University Feinberg School of Medicine, and her colleagues sought to determine if the same holds true for older people.
The researchers conducted the study with 13 adults age 60 and older, all of whom spent two nights in a sleep lab. During one night, participants received acoustic stimulation incorporating pink noise synced to their brain waves as they slept. The other night, no noise was played. Before and after each sleep session, they took a memory test to monitor any change.
Listen to an example of pink noise here.
The results were extraordinary—those who had listened to the pink noise as they slept performed three times better on the morning memory tests than they did after the other sleep session, according to the findings.
However, the effectiveness of pink noise is all about the timing. Sounds were distributed to match the participants’ slow-wave oscillations.
“The effect here, at least for memory, is quite related to the ability of the sound stimulus to enhance slow-wave sleep,” Zee told Time. “That’s very much tied to what part of the slow wave the stimulus is hitting on.”
Larger and longer studies are necessary to confirm the findings and show benefits to long-term use, but Northwestern is looking to produce new technology with this capacity for older adults. In fact, one of the study authors cofounded a company that intends to market the tech commercially.
So if you want deeper sleep and a memory boost, consider the soothing sounds of pink noise. Your body and brain will certainly thank you.