Abstract
Intellectual working tasks like a VDT task which cause mental strain are mainly performed in a modern office. Performing the tasks for several hours causes increasing fatigue, decreasing alertness and performance. But behaviors of refreshment (RF) can reduce these affects. The purpose of this study was to evaluate temporal variability characteristics of the mental and physiological state with the unforced RF during the intellectual working task in a sitting posture.
As a result, heart rate after the unforced RF was lower than that before the unforced RF for several minutes. And the high frequency power of R-R interval variability (HF) as an index of parasympathetic nerve activity after the unforced RF was higher than that after the forced RF for several minutes. The temporal variability of heart rate and HF with short-time unforced RF showed the characteristics which reached deactivated and less strained state briefly, then recovered a default state. These results suggest that the amplitude of these variability characteristics can be higher with an office environment which supports occurring short-time unforced RF and the briefly effects of the unforced RF reducing workload caused by intellectual working tasks in the office may become greater.
