We investigated whether changes in oxygen supply and demand from night to morning are different in hypertensives as compared to normotensives. A secondary goal was to investigate whether pressures measured non-invasively and intra-arterially give similar results.To this end we analyzed 24 h blood pressure and heart rate recordings using continuous and simultaneous intra-arterial brachial pressure and non-invasive finger arterial blood pressure tracings. Data were obtained in 14 hypertensive patients and in 8 healthy normotensive volunteers as part of a previous study [23]. Aortic pressure reconstructed from both brachial and finger pressures were analyzed to determine indices, which are accepted as parameters related to cardiac oxygen supply, cardiac oxygen demand, and the supply–demand ratio. We hypothesized that besides the well known increase in cardiac oxygen demand indices, additionally cardiac oxygen supply will decrease after rising.