century. BP is highest in early to mid-morning and falls progressively all through the day. BP is lowest at night (nocturnal dip) and BP rises before waking (morning surge).

ABPM has consistently shown that sleep-time BP mean is a better predictor of CVD events than daytime or 24-hour BP means. Modification of timing of the drug alters the cicardian rhythm → converts nondippers to dippers (J Am Soc Nephrol. 201;22(12):2313-21).

RAAS blockers have been well tried to modify this physiological phenomenon where shifting from morning dose to evening dose is done. Several of pathophysiologic systems responsible for the circadian BP variability, especially salt-balance and the RAAS, can be modulated by appropriate long-term therapy.

The physiological basis of the concept is so overwhelming that it has been appreciated by the Nobel Committee this year to recognize three Physiologists with the Nobel Award in Medicine in 2017.