How they affect Endel sound
Universal Energy Cycles
You should notice energy level hints at the main Endel screen, marking the current phase of biological rest-activity, and sleep-wake cycles — typically known as ultradian and circadian rhythms. Phases change every 20 minutes, with varying highs and lows that form a daily cycle. This variation is universal to life on Earth.
Harmonizing your periods of high and low activity with this cycle is a natural way to boost your daily productivity and wellbeing. See where you are on the chart below and choose your next move accordingly, then pick a matching Endel soundscape.
This is a basic 24-hours model of a perfectly productive day, as suggested by studies of human biological rhythms. Everyone is unique and deals with their own unique stresses, which shift this pattern. Our goal is to personalize this daily energy curve for every Endel user.
Ultradian rhythm is a rest-activity cycle that regulates cognitive state, mood, and energy level. It consists of roughly 110-minute loops of the energy’s up and down phases.
Circadian rhythm is a sleep-wake cycle that regulates the secretion of a sleep hormone called melatonin. It repeats every 24 hours and is constantly fine-tuned through natural light level.
Endel uses these universal rhythms as a baseline for sound personalization.
Personal Inputs
Personal inputs — heart rate, weather, motion type, and natural light — allow Endel to help you realign with the circadian and ultradian rhythms. This is made possible through an adaptive soundscape.
The most important input for the soundscape playing is shown in-app below the circadian/ultradian phase.
Natural light
Light has the biggest impact on the circadian rhythm. Even if you aren't exposed to it directly, your body is sensitive to changes in light conditions. Endel tracks natural light level and compensates by adapting your soundscape, changing sound intensity to maximize your comfort level.
Heart rate
Endel adjusts the beat to your resting heart rate by comparing it to your real-time heart rate using data from the Health (iOS) or Google Fit (Android) app.
Weather
Endel reacts to outdoor temperature with sound layer variations.
Motion type
Endel alters sound intensity according to the number of steps taken per minute.
Sound Personalization
Endel’s sound engine — Endel Pacific — consists of sound layers, modulations, and effects — all created in line with psychoacoustic studies. An algorithm processes user-state information and generates an appropriate soundscape by constructing unique combinations of Endel Pacific's components.
Soundscapes adjust automatically throughout the day and adapt based on user-state inputs — to provide the right sound intensity at any phase of the biological rhythms.