"The older we get the more likely our circadian rhythms are disrupted. For example blood pressure BP not only tends to increase but as well become more irregular. Luckily as we show in our research melatonin helps to ameliorate both trends.  senior respondents of a mean age of  were studied during  consecutive weeks. First week control data were collected for  successive days. Over the next  weeks the seniors were administered a low dose of melatonin . mg each day by night at  p.m. On the third week data were monitored again. Melatonin significantly reduced BP. The hypotensive effect was dependent on time. The maximum systolic BP lowering effect of melatonin falls between  and  in the morning the time of the highest risk of heart attacks and strokes. Nighttime and morning BP decreased more profoundly on average . mm Hg for SBPDBP respectively.  Moreover the higher the mean systolic BP was during the first week the more it dropped on the second week of melatonin administration. Melatonin also decreased the overall variability in BP.  Melatonin ws effective in synchronizing disrupted circadian rhythms of BP heart rate and body temperature making these circadian rhythms smoother and less irregular. None of these effects was found in  placebo treated seniors thus ruling out the possibility that rhythms could be improved just because of regular schedule and presence of medical personal who took measurements. In conclusion melatonin can be of great value for aged people suffering from hypertension as an adjuvant substance complementing basic medication as it is able to stabilize circadian BP heart rate profiles and their phase relationships. The improvement of circadian pacemaker functions may also provide a new strategy in the treatment of hypertension.   Denis G. Gubin Gennady D. Gubin Ludmila I. Gapon and Dietmar Weinert Tyumen Medical University Odesskaya   Tyumen Russia Reference Gubin D.G. et al. . Daily Melatonin Administration Attenuates AgeDependent Disturbances of Cardiovascular Rhythms Curr. Aging Sci. DOI ."