An apparatus (100a, 100b) for estimating blood pressure, the apparatus comprising: a sensor configured to measure a bio-signal from a subject; and a processor configured to acquire, from the bio-signal, a first feature value associated with cardiac output, CO, and a second feature value associated with total peripheral resistance, TPR, determine whether a current mechanism of blood pressure change of the subject is a post-exercise hypotension mechanism by comparing at least one of the first feature value, the second feature value, a first normalization value obtained by dividing the first feature value by a first reference feature value, a second normalization value obtained by dividing the second feature value by a second reference feature value, a difference between the first feature value and the second feature value, and a difference between the first normalization value and the second normalization value, with a preset threshold, wherein the first reference feature value and the second reference feature value respectively correspond to a value associated with the CO and a value associated with the TPR, which are obtained from the bio-signal measured at a time of calibration, calculate a first variation of a first normalization value relative to a reference point in time and a second variation of a second normalization value relative to the reference point in time, when it is determined that the current mechanism of blood pressure change is the post-exercise hypotension mechanism, estimate blood pressure using the calculated first variation and second variation with (i) adjusting the first variation and/or the second variation, or (ii) using an offset for correcting an error between an estimated blood pressure and actual blood pressure, and when it is determined that the current mechanism of blood pressure change is not the post-exercise hypotension mechanism, estimate blood pressure using the calculated first variation and second variation without (i) adjusting the first variation and/or the second variation, or (ii) using the offset. a sensor configured to measure a bio-signal from a subject; and a processor configured to acquire, from the bio-signal, a first feature value associated with cardiac output, CO, and a second feature value associated with total peripheral resistance, TPR, determine whether a current mechanism of blood pressure change of the subject is a post-exercise hypotension mechanism by comparing at least one of the first feature value, the second feature value, a first normalization value obtained by dividing the first feature value by a first reference feature value, a second normalization value obtained by dividing the second feature value by a second reference feature value, a difference between the first feature value and the second feature value, and a difference between the first normalization value and the second normalization value, with a preset threshold, wherein the first reference feature value and the second reference feature value respectively correspond to a value associated with the CO and a value associated with the TPR, which are obtained from the bio-signal measured at a time of calibration, calculate a first variation of a first normalization value relative to a reference point in time and a second variation of a second normalization value relative to the reference point in time, when it is determined that the current mechanism of blood pressure change is the post-exercise hypotension mechanism, estimate blood pressure using the calculated first variation and second variation with (i) adjusting the first variation and/or the second variation, or (ii) using an offset for correcting an error between an estimated blood pressure and actual blood pressure, and when it is determined that the current mechanism of blood pressure change is not the post-exercise hypotension mechanism, estimate blood pressure using the calculated first variation and second variation without (i) adjusting the first variation and/or the second variation, or (ii) using the offset.