Backgroud Sleep deprivation (SD) is a common phenomenon in emergency, especially during war time, conflict, natural disasters or disease crisis such as SARS, it can cause exhaustion in members of armed forces and non-combat casualty. In conditions of high-tech war, deprivation is becoming more serious and mandatory than ever before.

Objective To study the impact of 24-h sleep deprivation on arrhythmia and heart rate variability (HRV).

Methods Soldiers were used as research objects, they were divided into normal group and the sleep deprivation group. 1. Heart rate, atrial premature beat, ventricular premature beat and heart rate variability were observed by 24-h ambulatory ECG during sleep deprivation. 2. The changes of serum cortisol levels were detected during sleep deprivation.

Results 1. After 24 h sleep deprivation, HF, SDNN and RMSSD significantly reduced, LF significantly increased, LF /HF showed a significant increase. 2. Part of volunteers presented atrial premature beats and ventricular premature beats. 3. The level of serum cortisol significantly increased.

Conclusion The underlying mechanism of alteration of arrhythmia and HRV after 24-h sleep deprivation would be ascribed to lower vagal activity and elevated sympathetic activity.