Sleep and Circadian Contributions to Nighttime Blood Pressure

A constant routine protocol is used to directly examine markers of circadian rhythmicity (e.g., melatonin and core body temperature). A constant routine protocol requires an individual to remain in a dimly lit room, in a constant semi-recumbent posture, and remain awake for more than 24 hours. It is one of two gold-standard research protocols for examining circadian rhythms in humans.