APPARATUS FOR MONITORING A SUBJECT

A sensor monitors a subject and generates a signal. A computer processor receives the signal, derives therefrom data related to a heart rate of the subject and/or a respiration rate of the subject, derives from the signal at least one subject status indication that the subject is: awake and not moving, moving and asleep, not moving, asleep, awake and moving and in a bed, in a particular sleep stage while asleep, and/or has been continuously in a bed over a previous in-bed period of at least 15 hours, determines a threshold of at least 0.7 times an aerobic heart rate threshold and/or at least 0.7 times an aerobic respiratory rate threshold, and generates an alert if the signal indicates that the physiological parameter of the subject exceeds the threshold for an amount of time determined in response to the subject status indication. Other applications are also described.