Math explains why your late night habits may be breaking your body clock

WATERLOO, Ontario — From the effects of late-night scrolling on phones to the changes brought about by daylight savings time, scientists are diving deep into the understanding of how these disruptions influence our body’s natural rhythms. Now, a team of international researchers are turning to math to find the answers.

Their focus is on the body’s circadian rhythms – the 24-hour cycles our body systems operate on, determining periods of wakefulness and rest. Central to this rhythm is a group of neurons in the brain termed the Suprachiasmatic Nucleus (SCN) or “master clock.” This cluster plays a crucial role in coordinating the body’s other internal rhythms. Yet, much about the SCN remains a mystery.

“Current society is experiencing a rapid increase in demand for work outside of traditional daylight hours,” says study lead author Stéphanie Abo, a PhD student in applied mathematics at the University of Waterloo in Canada, in a university release. “This greatly disrupts how we are exposed to light, as well as other habits such as eating and sleeping patterns.”

Long-term disturbances to our circadian rhythms have adverse health implications, including risks of diabetes, memory loss, and various other disorders.

To unravel the complexities of the SCN, researchers turned to mathematical modeling techniques and differential equations. They viewed the SCN from a macroscopic perspective, envisioning it as a vast system made up of countless neurons. A key aspect of their research was deciphering the system’s couplings – the connections or pathways between these neurons that allow them to synchronize and maintain a shared rhythm.

Their findings reveal that sustained interruptions to our body’s circadian rhythms can erode this shared rhythm. This suggests that the communication signals between SCN neurons weaken.

However, there were some surprising discoveries. Abo points out that “a small enough disruption can actually make the connections between neurons stronger.”

“Mathematical models allow you to manipulate body systems with specificity that cannot be easily or ethically achieved in the body or a petri dish,” notes Abo. “This allows us to do research and develop good hypotheses at a lower cost.”

The study was published in the SIAM Journal on Applied Dynamical Systems.

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