Circadian heart rate and blood pressure variability considered for research and patient care.

Objectives: To review mechanisms of circadian variations in heart rate variability (HRV) and blood pressure variability (BPV) and mortality and morbidity due to cardiovascular diseases (CVD).

Methods: Results from 7-day/24-h HRV and BPV are interpreted by gender and age-specified reference values in the context of a Medline search.

Results: Abnormal HRV and BPV measured around the clock for 7 days provides information on the risk of subsequent morbid events in subjects without obvious heart disease and without abnormality outside the conventional (in the sense of chronobiologically unquantified) physiological range.