Association Between Augmentation Index and Total Sleep Time in Night Shift Workers

Area of Science:

• Cardiovascular physiology
• Occupational health

Background:

• Shift work is associated with increased cardiovascular risk, but the underlying mechanisms, particularly the role of sleep duration, are not fully understood.
• Augmentation index and pulse wave velocity are established markers of vascular compromise and predictors of cardiovascular events.

Purpose of the Study:

• To investigate the association between total sleep time and vascular markers (augmentation index, pulse wave velocity, central blood pressure) in night shift workers.
• To explore the relationship between sleep duration and early cardiovascular outcomes in individuals engaged in shift work.

Main Methods:

• Cross-sectional study involving 63 nursing shift workers and 17 day workers.
• Total sleep time was assessed using 10-day actigraphy.
• Vascular parameters including augmentation index, pulse wave velocity, and central/brachial blood pressure were measured using oscillometry.

Main Results:

• No significant differences in vascular parameters were observed between shift workers and day workers.
• Pulse wave velocity and blood pressure measures showed significant inter-correlations, but not with augmentation index.
• A U-shaped association was found between total sleep time and augmentation index in shift workers (p < 0.001), with the lowest augmentation index observed at 300-360 minutes of sleep.

Conclusions:

• Total sleep time exhibits a U-shaped relationship with augmentation index in shift workers.
• Optimal vascular functionality in this cohort was associated with a total sleep time of 5-6 hours.
• Further research is warranted to elucidate the specific impact of sleep duration on vascular health in shift-working populations.