The FEBS journalAug 24, 2026

When the body’s internal clocks stop working in cold temperatures

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Aug 25, 2026

Abstract

Circadian rhythms can weaken or disappear at temperatures within the broader survival range of organisms, defining an arrhythmic zone (AZ).

The arrhythmic zone is characterized by a temperature range where organisms retain viability but lose their autonomous circadian rhythms.
In cyanobacteria, clock failure occurs around 19°C, while Arabidopsis shows disrupted rhythmicity at 4°C.
Mammalian suprachiasmatic nucleus tissue displays arrested molecular rhythms below approximately 15-17°C.
Evidence for low-temperature impacts on circadian function has been observed in diverse organisms such as plants, fungi, insects, and marine invertebrates.
The strength and mechanisms underlying low-temperature clock failure vary among different biological systems.

Simplified

Circadian clocks are endogenous oscillators that coordinate physiology and behavior with the 24-h day-night cycle. Temperature compensation-the maintenance of a near-constant period across a range of temperatures-is a hallmark of circadian systems, but it has a lower bound. In diverse organisms, circadian rhythms can weaken or disappear at temperatures that remain within the organism's broader physiological survival range. We refer to this interval, where viability is retained but autonomous rhythmicity is diminished or lost, as the "arrhythmic zone" (AZ): the temperature range bounded above by the lower critical temperature for circadian rhythmicity and below by the organism's minimum viable temperature. Evidence for such low-temperature clock failure has been reported in cyanobacteria, plants, fungi, insects, marine invertebrates, and mammals, although the strength and mechanistic resolution of that evidence vary across systems. In cyanobacteria, low-temperature clock failure occurs through Hopf bifurcation at ~ 19°C, whereas in Arabidopsis rhythmic clock gene expression is strongly damped or disrupted at 4°C, and in hibernating mammalian SCN tissue molecular rhythms arrest below ~ 15-17°C, all at temperatures within the organism's broader survival range. This review synthesizes evidence for low-temperature limits of circadian function across model systems, examines candidate mechanisms of clock failure, evaluates hypotheses for possible adaptive significance, and highlights the near-complete absence of circadian data from true psychrophiles.