Does overnight duty affect vascular endothelial function?

Abstract

Background The reactive hyperemia index (RHI), which is obtained from the measurement of peripheral arterial tonometry (PAT), is highly associated with the percentage change in the end-diastolic arterial diameter (%flow-mediated dilatation) at reactive hyperemia. Low RHI is reported to be a mortality risk in patients with a high risk of cardiovascular (CV) disease. CV events are thought to be induced by physical and mental stress, including long-term fatigue and lack of sleep. However, the relationship between fatigue, lack of sleep, and endothelial function has not yet been established. Methods Healthy hospital workers (n = 13, 6 men and 7 women) with an average age of 31.6 years were assigned to this study after they provided written informed consent. During the study period, we conducted 72 measurements of reactive hyperemia-peripheral arterial tonometry (RH-PAT) in the morning before or after their duty. At each measurement of the RH-PAT, we recorded the participants’ hours of sleep and evaluated their degree of fatigue using a visual analog scale (VAS). Results Although the VAS was significantly less (36 ± 16% and 64 ± 12%, p < 0.001) and the hours of sleep were longer (6.0 ± 1.1 h and 2.3 ± 1.0 h, p < 0.001) before duty compared to those after duty, the RHI was comparable between them (2.12 ± 0.53 vs. 1.97 ± 0.50, p = 0.21). The VAS score was significantly higher in participants with low RHI (< 1.67) than in those with normal RHI (≥ 2.07) (59 ± 13% and 46 ± 21%, respectively, p < 0.05). However, binary logistic regression showed no significant association between low RHI and the VAS when adjusted for systemic blood pressure (SBP) and heart rate variability (HRV). In a simple regression analysis, the RHI was significantly correlated with the VAS score but not with sleep duration. A multiple linear regression analysis also showed no significant association between the RHI and VAS scores after adjustment for SBP and HRV. Conclusions Vascular endothelial function was not associated with overnight duty, hours of sleep, or degree of fatigue in healthy young adults. Since the RHI may be decreased in severe fatigue conditions through autonomic nerve activity, one should consider the physical and mental conditions of the examinee when evaluating the RH-PAT results.

Acute Effect of Night Shift Work on Endothelial Function with and without Naps: A Scoping Review

“…However, none of these five studies addressed the comparison of interest: the effect of napping/sleeping during night shift work (compared to no napping/sleeping) on the non-invasive indicators of endothelial function. We charted the key findings from these five ancillary articles [28,[47][48][49][50], which can be accessed in Appendix B. Below, we describe these studies along with the research gaps.…”

“…We identified five unique ancillary studies with a cumulative study sample of n = 110 individuals, of which 87% were shift workers [28,[47][48][49][50]. Amir and colleagues enrolled 30 healthy physicians working at a hospital in Israel [28].…”

“…Among the enrolled, 22 were physician residents (17 internal medicine and five surgery) and eight fellows (six cardiology, one gastroenterology, and one hematology). Garu and colleagues enrolled 13 hospital workers with night duty working at a hospital in Japan [47]. This group included six men and seven women.…”

Acute effect of blueberry intake on vascular function in older subjects: Study protocol for a randomized, controlled, crossover trial

“…RHI represents an alternative method to flow-mediated dilatation (FMD), the reference method, since it has the advantage of being simple, operator independent, and therefore less prone to operator bias and variability [36,51]. In addition, RHI has shown a significant correlation (r = 0.55, p < 0.0001) with FMD [52,53] and it is widely used, alone or in combination with FMD and/ or other markers of vascular function, not only for clinical practice but also to study the effect of drugs, supplements, foods and exercise in numerous human interventional trials [54][55][56][57][58]. Regarding the secondary outcomes, a wide range of metabolic and functional markers related to the aging process, and directly and/or indirectly associated to vascular function, has been identified.…”

Sleep Deficiency as a Risk Factor for Hypertension: A Systematic Review

“…This causes blood vessels to tighten, raising blood pressure and possibly developing hypertension [41]. Another study found that intracellular magnesium concentrations and flow-mediated arterial dilation were reduced during prolonged sleep deprivation [42].…”