Program running versus problem solving: two patterns of cardiac response

Our previous research showed that mental tasks that involve program running (RUN tasks), e.g. performing arithmetic operations, cause greater tonic increase in cardiovascular activity than tasks that require a search for problem solutions (EDIT tasks), e.g. logical completion of a series of digits. However, it was not clear what physiological mechanism was responsible for this difference. The aim of the experiment was to compare cardiac response patterns while solving three mental tasks matched for their duration and level of difficulty: a simple RT task (control task) and two numerical tasks: RUN and EDIT. Forty-eight males, university students, divided randomly into three groups (n=16), participated in the experiment. Each group performed a different task. Task-evoked changes in heart rate (HR), strong volume (SV), cardiac output (CO), pre-ejection period (PEP), and power of HF component of heart rate variability were subject of the analysis. The results showed a higher tonic HR increase during the RUN task than the two other tasks and larger shortening of PEP during the RUN than the EDIT task. The HF power was larger during the RT task than the RUN task. No significant between-task difference was found in SV and CO changes. The results seem to support the hypothesis that higher cardiac responsiveness to RUN than EDIT tasks is mainly due to the difference in sympathetic activation.