Hypertension is a common condition with a concomitant burden of stroke, kidney disease and myocardial infarction. Its prevalence in developed societies is increasing as they age, and in less developed countries, as their populations assume aspects of the Western diet and lifestyle. Nocturnal non-dipping hypertension (NDHT) - the failure of blood pressure (BP) to dip at night - is estimated to complicate \ 40% of hypertensives and is associated with poor outcomes. Randomized controlled trials have shown that a reduction of daytime systolic blood pressure by as little as 5mmHg on average (towards a target of 140mmHg) translates into a measurable clinical benefit. The peak nocturnal difference may be \ 15-20mmHg systolic, illustrating the substantial potential for incremental benefit by adequate blood pressure control across the 24 hour cycle in this population. In this study, the investigators wish (i) to establish through repeated assessment, the stability of the non-dipping phenotype (Phase 1), and (ii) to deeply phenotype non-dippers by using parameters assessing day/night patterns, the chronobiome (Phase 2). To facilitate data collection over the course of the study, the investigators use wearable devices and mobile phone applications.