Stress and habits disrupt sleep and fuel mental rumination, experts say

Health experts explain that poor sleep often results from a combination of stress, irregular schedules, late‑night light exposure, heavy meals, warm bedrooms, and the use of phones before bed. The French National Institute of Health stresses that insomnia usually develops gradually as these factors accumulate, and that monitoring sleep patterns can help identify reversible causes.

Psychologists warn that mental rumination—a repetitive, involuntary focus on negative thoughts—can worsen anxiety and further impair sleep. Christian Payá describes it as "a mental rumination resembles an attempt to solve a problem by reflection, but instead of reaching a resolution it keeps us turning in circles." He adds that "ruminating is often an attempt to relieve the unease caused by uncertainty." When rumination becomes frequent, interferes with work or sleep, and is linked to depression or anxiety, professional help may be needed.