Effects of Insufficient Sleep on Blood Pressure Monitored by a New Multibiomedical Recorder

TLDR

Blood pressure is influenced by physical activity, body position, ambient temperature, and autonomic nervous system activity. The study developed a portable multibiomedical recorder to monitor blood pressure, activity, position, temperature, and ECG, and used it to investigate how insufficient sleep affects blood pressure. Eighteen male technical workers wore the recorder for 24 hours during normal (8 h) and insufficient (3.6 h) sleep periods to record the five parameters. After a night of insufficient sleep, systolic/diastolic blood pressure rose, heart rate and sympathetic markers (LF/HF ratio, norepinephrine) increased, while temperature, activity, and posture remained unchanged, indicating that sleep loss elevates sympathetic activity and blood pressure.

Abstract

Abstract Blood pressure varies in relation to factors such as physical activity, body position, ambient temperature, and autonomic nervous system activity. Therefore, we have developed a portable multibiomedical (PMB) recorder that monitors five parameters: indirect blood pressure, physical activity, body position, ambient temperature, and RR interval of the electrocardiogram. In the present study, we applied the PMB recorder over a 24-hour period to study the effect of insufficient sleep on blood pressure in subjects doing extensive overtime work. The parameters listed above were measured by the PMB recorder throughout a normal workday (mean period of sleep, 8 hours) and throughout a day with insufficient sleep (mean period of sleep, 3.6 hours) in 18 male technical workers aged 23 to 48 years old. Blood pressure (mean systolic/diastolic pressure±SD) significantly increased the day after a sleep-insufficient night (129±8/79±6 mm Hg) compared with the day after a normal night (123±8/76±7 mm Hg, P <.05). However, ambient temperature, mean number of steps per minute, and percentage of time spent in a standing position showed no significant difference between these days. Spectral analysis of RR intervals showed that the ratio of the low-frequency component on the RR power spectrum (0.05 to 0.15 Hz) to the high-frequency component (0.15 to 0.40 Hz) was higher on the sleep-insufficient day (2.17±0.37 versus 1.81±0.37), as was the urinary excretion of norepinephrine ( P <.05). Heart rate was significantly higher on the sleep-insufficient day (81±11 versus 76±8 beats per minute), after the data of two subjects with abnormal levels of physical activity were excluded ( P <.01). These data suggest that lack of sleep may increase sympathetic nervous system activity on the following day, leading to increased blood pressure. The PMB recorder was useful for precisely evaluating the relationship between blood pressure and environmental factors.