Abstract: A heating device is provided comprising: a wearable layer conformable to a part of a user's body; a heat source attached to the wearable layer for applying heat to a region of a user's body; a blood flow sensor attached to the wearable layer configured to detect a parameter indicative of blood flow in or adjacent to the region of the user's body and generate a signal indicative thereof; and one or both of: (i) a processor in electrical communication with the blood flow sensor for determining the blood flow in or adjacent to the region of the user's body based upon the signal; or (ii) a transmitter for transmitting the signal to a remote device.