The present invention provides techniques for non-invasive measurement of blood related parameters based on NMR (nuclei) relaxation techniques carried out using a relatively low constant magnetic field in the range of 0.15 to 0.5 Tesla. A plurality of electromagnetic excitation pulse sequences having relatively low radiofrequencies are applied over a living tissue placed in the magnetic field and blood related parameters of the examined subject are determined using a plurality of nuclear spin echo signals received from the tissue in response to the applied excitation sequences, thereby allowing to improve the accuracy of the obtained signals and substantially reducing the time duration of the process.