You've heard of white noise, but what's brown noise and how does it impact our wellbeing?

Acoustics have a powerful impact on our wellbeing and our quality of life, but sound is not often given the consideration it deserves. We know when we like the sound of something, whether there's a song that energises us or makes us calm down, but we don't often think about why.

Studies show that high noise levels increase stress and blood pressure, negatively impact our quality of sleep and have a catalogue of other short- and long-term health issues.

Harvard Medicine said:

"... noise pollution not only drives hearing loss, tinnitus, and hypersensitivity to sound, but can cause or exacerbate cardiovascular disease; type 2 diabetes; sleep disturbances; stress; mental health and cognition problems, including memory impairment and attention deficits; childhood learning delays; and low birth weight. Scientists are investigating other possible links, including to dementia."

Even Florence Nightingale is said to have commented, “Unnecessary noise is the most cruel absence of care that can be inflicted on the sick or well.”

However, lots of us live with sound and simply accept it. Often we become so used to it that we don't even notice it's there. For example, we might become accustomed to the persistent hum of a motorway in the distance.

A colour spectrum of sound

Turning to the therapeutic side of sound however, in recent years there have also been more conversations about types of noise. There's a whole colour spectrum of noise in fact, ranging from violet to blue, white, pink and brown/red, each is defined by the relative intensity of different frequencies of sound and all with their respective benefits. The most frequently discussed are white, brown and pink noise.

White noise

Not all noise is negative however. In fact lots of us find total silence quite disconcerting. White noise is often used to mask more annoying sounds, like traffic. Lots of babies love it because it apparently resembles sounds from the womb and can create a cosy environment. In fact lots of people swear by white noise machines to help their babies sleep.

The Sleep Foundation describes it, saying: "White noise refers to a noise that contains all frequencies across the spectrum of audible sound in equal measure [...] Researchers have studied the effect of white noise on humans for many years, finding evidence it can reduce crying in infants, improve work performance, and potentially help counteract symptoms of attention-deficit/hyperactivity disorder (ADHD). Multiple studies have also examined how white noise may affect human sleep."

Brown noise

Brown noise, also called red noise, is another broadband sound like white noise. It contains sounds from every octave of the sound spectrum. To us it sounds deeper than either white or pink noise and often resembles the sound of rain. The New York Times describes it, saying: "It’s soothing, steady, slightly rumbly."

They continued, saying: "picking up speed in online A.D.H.D. communities, where people made videos of their reactions to hearing it for the first time. Many said it allowed their brains to feel calm, freed from an internal monologue. Some invited their viewers to try it too, and commenters chimed in, claiming that brown noise was not only a tool to help them focus, but could relieve stress and soothe them to sleep."

The name comes from Scottish botanist Robert Brown, who discovered 'Brownian motion', which is the way pollen grains suspended in water move under a microscope. Brown noise is said to mimic that motion. As for its benefits on focus or sleep, the jury's still out.

Pink noise

Pink noise is a softer version of white noise, playing lower frequencies a bit louder than its counterpart. To the human ear it's often considered more relaxing than white noise, and the Sleep Foundation relates it to sounds in nature, like wind and rain or even elements of birdsong.

They write: "Pink noise is often used as a background or control noise because research has found that it is less distracting than other types of noise. For example, one study found that participants became less stressed after listening to pink noise, compared with the typical sounds of an intensive care unit."

They note that some studies have found that pink noise may help people fall asleep faster and get a better, deeper sleep.

Sound in spa wellness

While quiet is associated with spa environments, sound is a pivotal part of the wellbeing experience, used both to establish the experience as well as in treatments. Spas will often feature tranquil music and the sound of running water to set the tone, while therapies ranging from the historic practice of Sound Baths, through to the optimised use of tech.

Sound baths

Sound baths work on the basis that everything around us and within us, whether we hear it or not, is on a vibration. It takes that idea and uses music for healing with instruments such as Tibetan singing bowls. The idea is that when our natural vibrations get out of tune, it is the root of illness. The instruments change the vibrations and get the body back into its own vibrational state.

Sensory deprivation floatation tanks

Lots of spas are employing the power of technology to enhance spa treatments on a multisensory level. For example, at the RE:TREAT spa at The Lowry Hotel, they use virtual reality as well as sensory deprivation and white noise. As a case in point, their sensory deprivation floatation tank removes all of the 'white noise' of life so you can properly relax and heal. It's time on your own in a tank full of water set to body temperature, and Epsom salts which make you float. When you are deprived of all sense stimuli - sight, sound, touch, smell - your mind switches off properly. In that state, your body can start healing itself - it's not using any muscles to hold itself up and you're not thinking about anything. You just drift in and out of consciousness for between 30- and 60-minutes.