Overview

• An observational analysis of more than 3,500 adults from the English Longitudinal Study of Ageing found a 23 percent higher long-term hair cortisol level in those reporting Monday anxiety compared with other weekdays.
• Researchers observed that elevated cortisol levels in hair samples persisted for as long as two months after the initial measurement.
• The prolonged stress response stems from dysregulation of the hypothalamus–pituitary–adrenal axis, the body’s primary stress control system.
• The biological reaction was equally strong in retirees and employed participants, suggesting weekly cultural rhythms rather than workplace pressures drive the effect.
• Experts say the findings offer a biological explanation for the long-noted spike in Monday heart attacks and strengthen calls for flexible work models such as four-day weeks or asynchronous schedules.