A method of operating an apparatus comprising a control unit to determine respiratory information for a subject, the method comprising: acquiring, by the control unit, one or more physiological signals indicative of at least one physiological characteristic of the subject; obtaining, by the control unit, contextual information relating to at least one of the subject and the one or more physiological signals; selecting, by the control unit, based on the contextual information, at least one signal processing algorithm for each of the one or more physiological signals, the at least one signal processing algorithm being adapted to determine respiratory information; and determining, by the control unit, respiratory information for the subject based on the one or more physiological signals using the at least one signal processing algorithm selected for the one or more physiological signals, wherein two or more signal processing algorithms are selected for at least one physiological signal, the two or more signal processing algorithms each being adapted to determine respiratory information, and the method further comprises: combining, by the control unit, the two or more signal processing algorithms selected for the at least one physiological signal into a combined signal processing algorithm; and determining, by the control unit, respiratory information for the subject based on the at least one physiological signal using the combined signal processing algorithm for the at least one physiological signal. acquiring, by the control unit, one or more physiological signals indicative of at least one physiological characteristic of the subject; obtaining, by the control unit, contextual information relating to at least one of the subject and the one or more physiological signals; selecting, by the control unit, based on the contextual information, at least one signal processing algorithm for each of the one or more physiological signals, the at least one signal processing algorithm being adapted to determine respiratory information; and determining, by the control unit, respiratory information for the subject based on the one or more physiological signals using the at least one signal processing algorithm selected for the one or more physiological signals, wherein two or more signal processing algorithms are selected for at least one physiological signal, the two or more signal processing algorithms each being adapted to determine respiratory information, and the method further comprises: combining, by the control unit, the two or more signal processing algorithms selected for the at least one physiological signal into a combined signal processing algorithm; and determining, by the control unit, respiratory information for the subject based on the at least one physiological signal using the combined signal processing algorithm for the at least one physiological signal. combining, by the control unit, the two or more signal processing algorithms selected for the at least one physiological signal into a combined signal processing algorithm; and determining, by the control unit, respiratory information for the subject based on the at least one physiological signal using the combined signal processing algorithm for the at least one physiological signal.