Abstract: Devices, systems, and methods herein relate to non-invasive cardiac monitoring of a cardiac parameter such as blood pressure. These systems and methods may receive and process user and cohort cardiac data to generate mechanical cardiac parameter values used to estimate blood pressure. In some variations, a method may include the steps of receiving mechanical cardiac data of a user measured using an accelerometer. A mechanical cardiac parameter value for a first time period and a second time period may be generated from the mechanical cardiac data. The blood pressure of the user may be estimated based on a change in the mechanical cardiac parameter value between the first and second time periods.