A 2025 study from the University of Hong Kong has found scientific support for what many of us feel at the start of the week—rising anxiety on Mondays.

Researchers analyzed data from more than 3,500 adults aged fifty and older living in England, uncovering what they call the “Anxious Monday effect.”

The team focused on the hypothalamic–pituitary–adrenal (HPA) axis, the hormonal network that governs how the body responds to stress.

When this system becomes dysregulated, it can alter metabolism, immunity, and emotional stability.

To measure real-world effects, scientists analyzed participants’ hair cortisol levels—an established biomarker that reflects long-term stress hormone exposure.

Over the two-month study period, participants showed, on average, twenty-three percent higher cortisol levels on Mondays than on other days of the week.

This pattern was observed not only in employed adults but also among retirees and non-working participants—suggesting that the physiological anticipation of a new week, rather than workplace stress alone, plays a role.

Lead author Tarani Chandola, PhD, notes that chronic disruption of the HPA axis can contribute to both physical and emotional health issues over time.

The findings highlight how even predictable weekly cycles can subtly shape our biology.

While more research is needed to understand why Mondays carry this stress signature, the study underscores a simple truth—our bodies keep the calendar, too.

Finding ways to ease into the week—through restful weekends, balanced routines, or mindfulness practices—may help soften that Monday edge.

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Adapted from: Chandola T, Ling W, Rouxel P. “Are Anxious Mondays Associated with HPA-Axis Dysregulation? A Longitudinal Study of Older Adults in England,” J Affect Disord. 2025;389:119611. doi:10.1016/j. jad.2025.119611