Table 2.

Within-group comparisons for parameters of heart rate variability.

	Exercise training (n=25)			Control (n=25)
	Pre	Post	P value	Pre	post	P value
SDNN(ms)	99.27(33.04)	130.96(57.76)	0.002	117.67(40.59)	117.69(40.71)	0.998
RMSSD(ms)	31.45(13.19)	36.26(18.97)	0.079	32.75(11.76)	30.67(14.11)	0.460
PNN50 (%)	6.90(7.40)	6.42(7.84)	0.986	8.22(7.04)	7.30(6.23)	0.715

Data are presented as the mean (SD). SDNN, standard deviation of normal R-R intervals; RMSSD, square root of the mean of the squares of successive R-R intervals differences; PNN50, percentages of differences between adjacent R-R intervals that are greater than 50 millisecond.