Lyssykluser

Lyssykluser, translated as light cycles, describe recurring patterns of light exposure characterized by the timing, duration, intensity, and spectral composition of light that an organism experiences over time. They are central in chronobiology and in fields such as horticulture and lighting design, where predictable light cycles are used to influence biological processes.

In animals, including humans, light cycles act as zeitgebers that synchronize internal circadian clocks to the 24-hour day. Key outcomes include rhythmic sleep-wake patterns, hormone release (for example melatonin), body temperature, and metabolism. The terms photoperiod and circadian entrainment are closely related.

In plants, light cycles regulate photoperiodism, affecting flowering time, tuber formation, and dormancy. The length of the daily light period can determine developmental transitions, and in agriculture controlled lyssykluser optimize yields and flowering schedules.

Measurement and implementation: researchers assess lyssykluser using light meters (lux or PAR), spectrally resolved measurements, and behavioral or molecular markers. In experiments, cycles range from short-nights to extended-day schedules, and may include gradual dawn-dusk transitions or abrupt on/off switching. In practical settings, lighting designers and growers implement fixed or dynamic cycles to sustain circadian alignment or optimize growth.

History and terminology: the study of light cycles emerged in the early to mid-20th century with the work of chronobiologists such as Jürgen Aschoff and Franz Halberg, and later photoperiodism researchers such as Garner and Allard for plants. Today, lyssykluser are a standard concept in circadian biology, sleep research, and horticulture.