Job-related stress and work ability of dispatchers in a metropolitan fire department

Table 3 Average heart rate (variability) and duration of the phases during the examined shift of the control group and the dispatchers

	Control group (n = 20)	Dispatchers(n = 27)	p^a
	Control group (n = 20)	Dispatchers(n = 27)	Control group vs. dispatchers
Event phases ^b , (median (min.-max.))
Cumulative duration, min	0 (0–60)	4.0 (0–47)	0.901
Number of events	0 (0–3)	0 (0–5)	0.006
beats/min	64.1 (57.5-69.8)	76.6 (72.2-87.4)	0.001
SDNN, ms	105.1 (58.8-159.7)	70.4 (40.4-152.9)	0.052
LF/HF	4.5 (1.3-14.9)	5.5 (0.4-30.1)	0.281
Non-event phases ^c , (median (min.-max.))
Cumulative duration, hours	6.7 (5.8-8.2)	9.1 (7.8-9.6)	0.001
beats/min	69.2 (59.9-79.3)	74.6 (56.4-89.8)	0.034
SDNN, ms	128.3 (59.2-357.6)	83.6 (65.1-158.6)	0.034
LF/HF	5.1 (2.6-14.2)	6.5 (1.2-11-0)	0.629
Breaks ^d , (median (min.-max.))
Cumulative duration, hours	0.5 (0–0.7)	1.5 (0.5-1.8)	0.001
beats/min	69.3 (64.0-82.3)	77.3 (60.3-89.3)	0.036
SDNN, ms	112.8 (56.1-155.9)	91.6 (53.8-267.0)	0.527
LF/HF	4.7 (1.8-9.8)	6.7 (1.7-30.1)	0.239

SDNN = standard deviation of all NN intervals.
LF/HF = ratio of low-high frequency power.
^aMann Whitney test.
^bTime periods during which the dispatchers had marked a stressful call/ a difficult caller or the internal control group had marked a subjectively stressful situation on the phase protocol.
^cWorking hours without stressful events.
^dTime outside working hours.
Significant findings are bold.

ISSN: 1745-6673