Stress and sleep interact in a vicious cycle: poor sleep heightens stress sensitivity, while stress disrupts the ability to fall and stay asleep. Under stress, the body activates its stress response system, releasing hormones like cortisol and adrenaline that boost alertness and physiological arousal—making rest harder to achieve. The timing of stress matters—stressful events in the evening are more likely to delay sleep onset and fragment sleep cycles. Work-related stress, especially in high-pressure professions, presents unique challenges for sleep health. Disrupted sleep also impairs immune defenses and emotional regulation, making it harder to cope with daily stress and increasing vulnerability to illness.