An apparatus comprising at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause a portable apparatus to perform operations comprising: determining that the portable apparatus is in an exercise mode; obtaining, by the portable apparatus when in the exercise mode, real-time exercise data of a user of the portable apparatus acquired using a sensor set having one or more sensors, and reference data indicating a measurement range for characteristic and/or uncharacteristic acceleration values related to the exercise mode; observing, when in the exercise mode, the real-time exercise data, and detecting, during the observing based on comparison of the real-time exercise data with the reference data, that at least one acceleration value of the exercise data is uncharacteristic to the exercise mode; and determining, when in the exercise mode, whether the detection of the at least one uncharacteristic value is related to an unpredicted incident, and as a response to the determining that the detection of the at least one uncharacteristic value is related to the unpredicted incident, causing an output of an emergency signal, wherein the exercise mode is one of a plurality of exercise modes each associated with a different exercise, the plurality of exercise modes comprising a first exercise mode and a second exercise mode, and the reference data comprises first reference data being specific to said first exercise mode and second reference data being specific to said second exercise mode, the first reference data and the second reference data indicating different measurement ranges for characteristic and/or uncharacteristic acceleration values, characterized in that the determining whether the detection of the at least one uncharacteristic acceleration value is related to the unpredicted incident comprises: continuing to obtain the real-time exercise data of the user, the real-time exercise data comprising cardiac activity data of the user; and after the detection of the at least one uncharacteristic acceleration value, determining, based on cardiac activity data, whether the detection of the at least one uncharacteristic acceleration value is related to the unpredicted incident. determining that the portable apparatus is in an exercise mode; obtaining, by the portable apparatus when in the exercise mode, real-time exercise data of a user of the portable apparatus acquired using a sensor set having one or more sensors, and reference data indicating a measurement range for characteristic and/or uncharacteristic acceleration values related to the exercise mode; observing, when in the exercise mode, the real-time exercise data, and detecting, during the observing based on comparison of the real-time exercise data with the reference data, that at least one acceleration value of the exercise data is uncharacteristic to the exercise mode; and determining, when in the exercise mode, whether the detection of the at least one uncharacteristic value is related to an unpredicted incident, and as a response to the determining that the detection of the at least one uncharacteristic value is related to the unpredicted incident, causing an output of an emergency signal, wherein the exercise mode is one of a plurality of exercise modes each associated with a different exercise, the plurality of exercise modes comprising a first exercise mode and a second exercise mode, and the reference data comprises first reference data being specific to said first exercise mode and second reference data being specific to said second exercise mode, the first reference data and the second reference data indicating different measurement ranges for characteristic and/or uncharacteristic acceleration values, characterized in that the determining whether the detection of the at least one uncharacteristic acceleration value is related to the unpredicted incident comprises: continuing to obtain the real-time exercise data of the user, the real-time exercise data comprising cardiac activity data of the user; and after the detection of the at least one uncharacteristic acceleration value, determining, based on cardiac activity data, whether the detection of the at least one uncharacteristic acceleration value is related to the unpredicted incident. continuing to obtain the real-time exercise data of the user, the real-time exercise data comprising cardiac activity data of the user; and after the detection of the at least one uncharacteristic acceleration value, determining, based on cardiac activity data, whether the detection of the at least one uncharacteristic acceleration value is related to the unpredicted incident.