FöRFATTARE
Fagerlönn, Johan

INSTITUTION
Systemteknik / Medieteknik

SAMMANFATTNING
The growing problem of stress in our society has provided greater motivation to seek stress solutions. This health threat demands a fresh thinking and exploration of new ways to find solutions. Music has in several studies been suggested to have a stress reducing effect. This report describes the development of a prototype that uses music to step by step help an individual to reduce stress. This is done by a combination of relaxing music and the biofeedback principle. The prototype estimates the individuals stress level by monitoring heart rate. On the basis of senor readings music is composed in real time to match the stress level. In that way a feedback loop is created where the individuals current stress level is reflected in the music. The music does not change from one song to the other; rather different parameters in the music are continuously changed such as tempo and instrumentation.

The report also includes a literature study examining heart rate as a valid stress indicator. This literature study is also complemented with an experimental study. In this study 14 participants, 7 males and 7 females, age between 21 and 54, were exposed to three different mental stressors separated with three minutes of relaxation. A version of Stroop color word test, a mental arithmetic task and a talk preparation. Heart rate was measured and the subjective estimation of stress level was given by the subjects before the first stressor, after each stressor and after each period of relaxation. A significant increase of heart rate (~10 bpm in mean) was detected in the end of each stressor compared to the periods of relaxation.

The important conclusion with the studies is that heart rate is a valid mental stress indicator, but the reliability is low since heart rate is influenced by many other factors than mental stress. In future development of BodyResT heart rate must be complemented with one or several other physiological parameters such as heart rate variability and skin conductance.

ISSN 1402-1617 / ISRN LTU-EX--05/283--SE / NR 2005:283