S-23-4: Effects of Rotating Night SHFT on Circadian Pattern of Ambulatory Blood Pressure/Heart Rate, Salivary Cortisol and Sulfatoxy Melatonin Levels

Abstract

Objective:The present study was aimed to investigate effect of Light exposute at night on 24 hours chronomics of BP/HR in terms of Double amplitude, Acrophase and Hyperbaric index and its relation with circadian rhythm of salivary cortisol and 6 sulfatoxy melatonin in rotating night shift nursing professionals and actual day workers.Design & Methods:56 night shift nurses, aged 20 to 40 years, performing day and night shift duties were recruited from the Trauma Center, KGMU, India, and 56 age sex matched actual day workers were also enrolled as controls. BP and HR were recorded by Ambulatory Blood Pressure Monitoring (ABPM) at every 30 min intervals in day time and each hour in night time during shift duties.Results:Highly significant difference was found in double amplitude (2DA) of among between night (23.10 ± 14.68) and day shift (34.27 ± 16.44) (p < 0.0005). In night shift, hyperbaric index (HBI) of mean SBP was found to be increased at 00 to 03 am (midnight) while during day shift, peak was found at 06 to 09 am. HBI of mean HR was found to be increased at 18 to 21 pm during night shift while in controls, peak was found at 09 to 12 & again 15 to 18 pm of SBP, DBP & HR. Alterations in Acrophase of BP/HR were very common among night shift workers and Ecphasia was found in few nights shift workers. Difference was found in night cortisol levels among night (4.08 ± 3.28) vs day shift (2.62 ± 2.37), while in comparison to night shift or day shift with controls (1.82 ± 1.18) these difference was significant (p < 0.05).Conclusion:Alteration in mean morning melatonin and Increased Night cortisol level were found during night shift. Reverse pattern of Acrophase and HBI of BP & HR along with salivary cortisol during night shift represents desynchronization. It indicates that the circadian rhythm was disrupted during night shift and recovery occurs during day shit.