Related Experiment Videos
Shift work modifies the circadian patterns of heart rate variability in nurses
1Fukuoka Health Promotion Foundation, Maizuru 2-5-1, Chuo-ku, Fukuoka 810-0073, Japan. h_ito@intmed1.med.kyushu-u.ac.jp
International Journal of Cardiology
|July 20, 2001
Summary
Shift work alters cardiac autonomic activity, with sympathetic control peaking during work and vagal control during sleep, irrespective of the clock hour. This highlights physical activity
Area of Science:
- Cardiovascular Physiology
- Chronobiology
- Occupational Health
Background:
- Shift work disrupts natural sleep-wake cycles.
- Circadian rhythms influence autonomic nervous system activity.
- Understanding these effects is crucial for shift worker health.
Purpose of the Study:
- To investigate how altering work-sleep schedules impacts the circadian rhythm of cardiac autonomic activity.
- To analyze heart rate variability (HRV) using spectral analysis.
Main Methods:
- 10 healthy Japanese female nurses participated.
- 24-hour ambulatory ECG recordings were obtained during day and night shifts.
- HRV frequency domain variables were analyzed across work, awake, and sleep states.
Main Results:
- Overall 24-hour HRV metrics did not differ between day and night shifts.
- Sympathetic activity markers (LFnu, LF/HF ratio) were highest during work and lowest during sleep.
- Vagal activity markers (HFabs, HFnu) showed the opposite pattern.
- HRV variables within specific activity states were consistent across shifts.
Conclusions:
- Cardiac autonomic activity's circadian rhythm is primarily modulated by physical activity levels, not clock time.
- These findings have implications for understanding cardiovascular disease risk in shift workers.
- Physical activity's role in autonomic regulation warrants further clinical consideration.