Unlocking Deep Sleep and Brain Health: How Pink Noise Boosts Memory and Cognitive Function

While the background sound-masking effects of white noise are well known—with regular travellers wearing white noise headphones to block out airplane hubbub and light sleepers using machines to protect against outside sounds—new research at the Massachusetts Institute of Technology has found that pink noise may help us sleep better and healthier.

“During the day, waste products such as lactic acid and worn-out proteins build up in the brain. When we sleep at night, waves of cerebrospinal fluid (CSF) help to wash away this waste, keeping the brain healthy,” notes MIT News about the research. In a new study, researchers at the Massachusetts Institute of Technology have shown they can strengthen these CSF waves through exposure to short bursts of a gentle, staticky sound known as pink noise during sleep, increasing the amplitude of slow electrical waves and enlarging the CSF waves.

Researchers believe the study could have far-reaching implications for boosting cognitive function, improving memory, aiding restorative sleep, and slowing neurodegenerative diseases caused by harmful proteins, such as Alzheimer’s, Parkinson’s, Huntington’s, and Creutzfeldt-Jakob.

Colours describe how sound energy is distributed across frequencies, from low-pitched rumbles to high-pitched hisses. Psychologist and neuroscience and psychotechnology researcher Nargiza Noimann-Zander explains that these are physical property labels rather than separate modes of brain activity. White noise has approximately equal power per hertz and the familiar hiss of radio static. Pink noise contains relatively more low-frequency energy with equal power in each octave, sounding less sharp like wind rustling through leaves or waves washing up on a beach.

Other colour noises include brown noise, sounding like heavy rainfall for concentration; grey and violet noises for tinnitus management; blue noise to cover sharp environmental sounds; and green and black noises promoting calmness. Dr Ash Shishodia, psychiatrist and neuropsychiatrist at Thrive Wellbeing Centre, explains that different noises contain different proportions of frequencies.

The brain’s natural glymphatic system flushes out waste proteins during deep sleep, but the process fails in those who regularly miss deep sleep. The study found that 50-millisecond bursts of pink noise at the peak of slow waves stimulated blood vessels to constrict and dilate, pushing CSF and waste proteins out of the brain. Since its discovery in 1925, pink noise has also been connected to Attention Deficit Hyperactive Disorder (ADHD) research.

Regarding concentration, Ms Noimann-Zander notes that a systematic review found small benefits from white or pink noise on laboratory attention tasks in people with ADHD, though others may not see the same benefit. Dr Shishodia advises keeping background noise comfortable and the volume low.