[Circadian variations of blood pressure]

Blood pressure (BP) exhibit diurnal variations with low level during night time and high level during daytime. There is little evidence of an endogenous mechanism of BP variations whereas a lot of clues show the contribution of external factors such as activity, mood, postures. Different pathophysiological conditions may alter the pattern of BP circadian variations. This is the case of severe hypertension, hypertension in the elderly and some secondary forms of the disease. Other pathological conditions concerned by BP rhythm alterations are dysautonomia, complicated diabetes, Cushing syndrome, organ transplantations. Methods currently in use to handle data are reviewed.