In accordance with some embodiments, systems, methods, and media for estimating compensatory reserve and predicting hemodynamic decompensation using physiological data are provided. In some embodiments, a system for estimating compensatory reserve is provided, the system comprising: a processor programmed to: receive a blood pressure waveform of a subject; generate a first sample of the blood pressure waveform with a first duration; provide the sample as input to a trained CNN that was trained using samples of the first duration from blood pressure waveforms recorded from subjects while decreasing the subject's central blood volume, each sample being associated with a compensatory reserve metric; receive, from the trained CNN, a first compensatory reserve metric based on the first sample; and cause information indicative of remaining compensatory reserve to be presented.