Table 6. Summary of primary heart rate variability according to aircraft noise.

Characteristics	Total (n = 35)	Low aircraft noise (n = 18)	High aircraft noise (n = 17)	F	P value
HR	74.96 ± 6.06	75.09 ± 5.00	74.81 ± 7.18	0.022	0.883
RMSSD	63.82 ± 23.82	64.01 ± 21.68	63.61 ± 26.57	0.074	0.787
NN50	124.01 ± 50.66	125.30 ± 44.21	122.65 ± 58.07	0.196	0.661
pNN50	36.52 ± 16.89	36.91 ± 15.80	36.10 ± 18.46	0.176	0.677
nLF	50.91 ± 12.89	52.56 ± 15.32	49.15 ± 9.87	0.000	0.994
nHF	49.09 ± 12.89	47.44 ± 15.32	50.85 ± 9.87	0.000	0.994
RATIO	1.31 ± 0.62	1.45 ± 0.74	1.15 ± 0.45	0.463	0.501
LF	1,826.63 ± 889.62	1,948.09 ± 766.84	1,698.03 ± 1,011.34	0.019	0.892
HF	1,771.54 ± 1,230.85	1,757.04 ± 1,148.05	1,786.88 ± 1,348.51	0.022	0.882
TP	9,056.11 ± 4,871.06	8,360.70 ± 2,970.78	9,792.42 ± 6,318.47	0.552	0.463

Data are shown as mean ± standard deviation.

HR = heart rate, RMSSD = root mean square of successive difference of successive normal-to-normal, NN50 = difference between adjacent normal-to-normal intervals of 50 ms or more, pNN50 = NN50/total number of all normal-to-normal, nLF = low-frequency power in normalized units, nHF = high-frequency power in normalized units, RATIO = LF/HF ratio, LF = power in low-frequency range, HF = power in high-frequency range, TP = total power.