Stress during sleep due to sleep restriction: HRV as a stress marker

Abstract

This study investigates the influence of sleep restriction and following recovery sleep on heart rate variability (HRV) as an indicator of autonomic cardiac stress. Nineteen healthy young female and male adults (aged 20–26) completed a 12-day, controlled laboratory study, including baseline sleep, a five-night sleep restriction phase, and recovery sleep nights, with polysomnography and ECG-based HRV measurements. HRV markers were calculated for light sleep (N2), deep sleep (N3), rapid eye movement (REM), and five-hour sleep segments. Statistical analysis with mixed ANOVA revealed significant reductions in parasympathetic HRV markers (SDNN, RMSSD, pNN50) and increased heart rate in the last sleep restricted night, with incomplete normalization during recovery sleep. REM and N3 sleep stages showed particular vulnerability to autonomic dysregulation, highlighting limited cardiovascular resilience to sleep restriction. Individual differences in HRV reactivity emphasize the requirement of a personalized approach to assessment and intervention. The results highlight the importance of sleep in preserving autonomic and CV health and suggest the need for prospective longitudinal studies with more prolonged recovery periods to examine their longterm risks/recovery.