In this study changes in biorhythm are observed by measuring heart rate
variabilities in order to verify, compare, and evaluate stresses in guard duties
of guards and CCTV monitoring works of staffs serviced in practical guard
sites. Guard duties and CCTV monitoring works similar to a practical situation
are implemented for nine students in the department of security at K University
over 150 minutes. In the results of observing heart rate variabilities and
autonomic function tests for six times with an interval of 30 minutes, the heart
rate variability (HRV) in CCTV monitoring works represents lower levels than
that of guard duties. Also, in a stable condition the guard duties for 30 and
60 minutes exhibit lower levels than that of 90, 120, and 150 minutes.
Regarding SDNN, CCTV monitoring works show higher levels that guard duties
and the guard duties for 30 and 60 minutes represent lower levels than that
of 150 minutes. In autonomic function tests, there are no differences in TP
between groups according to guard duties and CCTV monitoring works. Also,
the guard duties for 150 minutes represent more differences in TP compared
to that of 30 minutes. The interaction between the duty type and the duty
duration is presented. In the case of LF, guard duties for 150 minutes show
large differences in duty duration compared to that of 60 minutes. In the case
of HF, the CCTV monitoring work group shows higher levels than the guard
duty group in which the guard duties for 120 and 150 minutes represent higher
levels than that of 30 minutes. The interaction between the duty type and the
duty duration is presented. In the case of the LF/HF ratio, the guard duty
group exhibits higher levels than the CCTV monitoring group. Also, there is
an interaction between the duty type and the duty duration including the
difference in durations. The CCTV monitoring works represent lower heart
function activities than the guard duties according to increases in
parasympathetic nervous activities. It shows that the long-term CCTV
monitoring duty repeated everyday shows a high possibility of increasing the
exposures of VDT syndrome and nervous breakdown.