Shift Work and Circadian Disruption

The role of autonomic and baroreceptor reflex control in blood pressure dipping and nondipping in rats

“…This definition implies two concepts, a daytimenight-time contrast and a wake-sleep contrast [11], because the light-dark cycle and the sleep-wake cycle are closely coupled in humans. Although findings from shift-workers suggest the sleep-wake cycle is the dominating factor in determining dipping status [6,8], it should be remembered in this context that a change in sleep habit per se is a disturbance to the circadian rhythm [48][49][50], making the exclusion of an effect caused by a disrupted circadian rhythm difficult to prove. However, rats seem to be a more appropriate animal model, because they normally sleep during both the light and the dark periods; thus no intervention is needed to change their sleep habits in order to separate dark-light and sleep-wake effects.…”