A monitoring apparatus for monitoring a subject (14) is disclosed. The monitoring apparatus comprises a storage device (18) for storing first skin secretion data (27) of the subject. A detection unit (12) detects a skin secretion at a skin portion of the subject and provides second skin secretion data (28) of the subject. An evaluation unit (16) evaluates the second skin secretion data and determines at least one physical parameter on the basis of the first skin secretion data and the second skin secretion data. One of the at least one physical parameter is a time value (25, 26) determinable on the basis of a difference between the first and the second skin secretion data.
