Measurement and analysis methods of heart rate and respiration for use in applied environments.

Cardiovascular measures are used in applied settings to assess mental load. It is neither desirable nor possible to adapt the working situation to the needs of the experimenter, as can be done in the laboratory; the purpose of this paper is to discuss how invested effort, mental efficiency, and changes in cardiovascular state can be measured in applied settings, including non-stationary ones. This paper discusses the theoretical background of fluctuations in heart rate and respiration and the application of existing methods in laboratory and normal working situations. Data acquisition and analysis methods are then presented, particularly the problems of artifact detection and correction and variability indices in spectral bands in relation to the reliability of these measures. In the last section the interpretation of data acquired in environments and the specific problems inherent in such situations are discussed.