Circadian rhythms: embedded within our genes

Light and the modern world


Most life on earth has adapted to the 24-hour light-dark cycle that underpins our physiology. Before industrialization and widespread availability of electricity, daily life was restricted to natural day-night periods. The introduction of electric lighting led to changes in our environment and the way we interact throughout the day.

55% of the world’s population now inhabit the cities, and we, the urban dwellers, no longer rely on the natural light-dark periods for our sleep-wake cycles. More importantly, we spend more than 90% of our time indoors exposed to artificial lighting. However, lighting standards in our environments are not tailored to be optimal for our health and well-being and often meet only minimal illuminance levels. This has had a profound impact on our physiology considering that light is the strongest environmental cue regulating the body’s circadian rhythms.


The evolution of light from 1879 to present.

Circadian rhythms

Circadian rhythms regulate our wakefulness and sleep. The circadian system is imprinted in our biology within genetic, cellular and physiological levels. The light information we receive from our environment is conveyed to master clock in the brain located in the suprachiasmatic nucleus (SCN) by photopigment melanopsin containing retinal ganglion cells in the retina. Signals are then projected from SCN to multiple areas pivotal to our biological rhythms and optimal functioning in the outside world.

Why light matters

Appropriate light exposure ensures the circadian rhythm synchronisation that is in line with our true inner biological clocks. It improves cognitive performance, alertness, productivity and mood throughout the day and sleep during the night through melatonin hormone production.


At LYS we are also focusing on the individual differences in the preferred timings of sleep and activity, so-called chronotypes. We all have different timings for ideal performance at work, exercise and bedtime. This morningness-eveningness information ensures that the predicted light impact on the body is even more precise and tailored to the individual.

LYS: Live healthier with light

Inspired by the latest research in sleep science, LYS looks beyond the lifespan of a lightbulb, aesthetics of a lamp, and the technology of smart lighting.

Instead, we focus on what should always come first: people and supporting their healthy livelihood. Our technology enables personal light adjusted to people’s inner rhythms and daily routines.

About LYS

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