Forget White Noise, Sleep Frequencies Might Be the Thing That Actually Transforms Your Rest, a Sleep Doctor Explains

These days, it feels like every week brings a new promise of perfect sleep. From mouth taping and white noise to chronologically retracing your day's activities, some bedtime hacks veer into the downright bizarre. But while a few trends deserve raised eyebrows, sleep frequencies might actually have more substance than most.

But wait, what exactly are sleep frequencies? As the name suggests, they're specific sound frequencies said to improve sleep. Unlike white noise or brown noise — which combine audible frequencies to create a steady, static-like hum — sleep frequencies focus on specific tones thought to promote better sleep by inducing deep relaxation at a neurological level.

If you're on a mission to discover how to sleep better and upgrade your wind-down routine, sleep frequencies could just offer the answer. To find out more, I spoke to a sleep expert to find out exactly what they are and how we can harness their benefits in the bedroom.

What Are Sleep Frequencies?

Sleep frequencies are specific sound frequencies that promote relaxation. They can take the form of sustained tones that feel calming and meditative, or they can be embedded in ambient music. Unlike color noise, which combines different frequencies for a static sound, sleep frequencies target specific brainwave activity.

Dr. Chad Eldridge is the sleep and wellbeing advisor at Swedish bed makers, Hästens, which founded the Restore® app to improve sleep, focus, and relaxation. He explains that during sleep, neurons fire in coordinated rhythmic patterns that appear on an EEG as brainwaves measured in hertz (Hz). "Different stages of sleep are associated with different frequency bands," he says. "For example, deep sleep is characterised by slow delta waves." It's these brainwaves that sleep frequencies aim to target.

"Commercial 'sleep frequencies' typically use rhythmic auditory stimulation, such as pulsed tones or binaural beats, designed to gently guide the brain toward a specific frequency," Dr. Chad explains. "This process, known as brainwave entrainment, aims to encourage the brain’s electrical activity to synchronize with the external rhythm, potentially increasing activity in sleep-supportive bands like delta."

How Do Sleep Frequencies Benefit Sleep?

If you're looking to foster a better wind-down routine for sleep, consider incorporating sleep frequencies to help you not only switch off faster but also sustain good rest. "In theory, these frequencies can help decrease stress and anxiety, promoting a calming effect — which is the optimal physiological state for falling asleep and supporting overall sleep quality," says Dr. Chad.

But, as with any theory surrounding sleep, the true benefits of sleep frequencies are often contested, with scientific research offering mixed findings. "As an approach, sleep frequencies are best viewed as supportive tools rather than standalone solutions," says Dr. Chad. "They are most effective when used alongside good sleep timing, a consistent routine, and an optimized sleep environment."

Dr. Chad Eldridge

Dr. Eldridge is a sleep expert and well-being advisor who is based in Los Angeles and works with a global client base. Using his Five Pillars of Health system, Dr. Eldridge helps his clients investigate all areas of their lives–movement, sleep, nutrition, emotions, and community — to create a customized plan for optimal health. He believes that the pursuit of health is ultimately a project of getting to know ourselves better. His client list includes professional athletes in the NBA, NFL, PGA, and MLB, as well as high-level executives and entertainers

What Are the Key Types of Sleep Frequencies?

There are different types of sleep frequencies, with each one targeting different pathways in the brain.

Binaural beats

Binaural beats are a type of auditory illusion that requires headphones. "Two slightly different tones are played separately into each ear — for example, 200 Hz in the left ear and 206 Hz in the right," says Dr. Chad. "The brain perceives a third 'phantom' beat equal to the difference between them (in this case, 6 Hz). This perceived beat can gently encourage brain activity to synchronize with that frequency band — a process known as brainwave entrainment."

Lower frequencies

Frequencies like Delta (0.5–4 Hz) and Theta (4–8 Hz)are typically used for sleep and relaxation. "Delta is associated with deep, restorative sleep and Theta is linked to relaxation, REM-like states, and meditation," says Dr. Chad. "Within the Hästens Sleep Restore app, these frequency principles are incorporated into guided soundscapes designed to help transition the nervous system from alertness into parasympathetic 'rest and digest' mode, supporting natural sleep architecture rather than forcing sedation."

Solfeggio frequencies

By contrast, Dr. Chad explains that solfeggio frequencies are single, pure tones set at specific fixed frequencies, often described as “ancient” or sacred tunings. "They are less about measurable brainwave entrainment and more about perceived resonance, emotional regulation, and stress relief," he says.

These resonant sounds usually range from 174 Hz to 963 Hz. "Headphones aren’t required, meaning they can be played through speakers, making them accessible for ambient bedtime routines," adds Dr. Chad.

Low-frequency ambient music

Usually tuned to 432 Hz or 528 Hz, this type of sleep frequency focuses less on altering brainwaves directly and more on reducing physiological arousal. "It aims to slow breathing, lower heart rate, and create a calming sensory environment," Dr. Chad explains.

While binaural beats are directly linked to brainwave entrainment, Solfeggio and ambient frequencies aim to support relaxation through mood, atmosphere, and nervous system regulation.

Wondering where to find these sleep sounds? YouTube is a good port of call, but some of the best sleep apps and tools (like the Hästens Sleep Restore app) make it easy to access them from your phone using thoughtfully designed tools. "These blend science-backed principles with sensory design to enhance restorative sleep," notes Dr. Chad.

What Is The Best Frequency to Fall Asleep to?

Instead of obsessing over pink vs white noise to help you fall asleep, it's worth putting more thought into the type of sleep frequency to target specific brainwaves. But what's the best type for promoting sleep?

"If using beats, delta would be ideal, which is around .5-4Hz," says Dr. Chad. "If using Solfeggios or others, look at 432/528 Hz." With many of us prioritizing tech-free bedrooms these days, he suggests using certain sounds in the build-up to bedtime, rather than while your head is on the pillow.

"432 Hz or 528 Hz ambient sound played softly over speakers before bed can help calm the nervous system," explains Dr. Chad. "Similarly, low-level pink, white, or brown noise can provide a steady auditory backdrop with minimal stimulation. These options tend to feel more 'analogue' and less intrusive, as binaural beats require headphones and therefore more direct tech interaction."

To the uninitiated, sleep frequencies might sound a little woo-woo, but look beyond the buzzwords and there's a growing body of credible research to suggest they do actually support deeper, more restorative rest.

Of all the bedtime trends and things to aid sleep that have crossed my desk in recent years, this one carries real weight. If you're curating a wind-down routine that actually delivers, you might want to dial into this latest sleep craze.