Table 2.

Individual associations of sedentary time, physical activity, and cardiorespiratory fitness with heart rate variability variables in boys

	SDNN			RMSSD			LF			HF			LF/HF
	β	95% CI	p	β	95% CI	p	β	95% CI	p	β	95% CI	p	β	95% CI	p
ST	− 0.166	− 0.31|− 0.02	0.026	− 0.185	− 0.33|− 0.04	0.012	− 0.156	− 0.30|− 0.01	0.037	− 0.146	− 0.29|− 0.001	0.049	0.060	− 0.09|0.21	0.417
LPA	0.031	− 0.12|0.18	0.682	0.021	− 0.13|0.18	0.773	0.069	− 0.08|0.22	0.355	0.006	− 0.14|0.15	0.936	0.070	− 0.08|0.22	0.343
MPA	0.113	− 0.03|0.26	0.127	0.158	0.01|0.30	0.032	0.067	− 0.08|0.21	0.369	0.111	− 0.03|0.26	0.133	− 0.105	− 0.25|0.04	0.154
MVPA	0.208	− 06|0.35	0.005	0.252	0.11|0.39	0.001	0.147	0.001|0.29	0.048	0.210	0.07|0.35	0.004	− 0.175	− 0.32|− 0.03	0.017
VPA	0.284	0.15|0.42	< 0.001	0.301	0.16|0.44	< 0.001	0.229	0.09|0.37	0.002	0.294	0.16|0.43	< 0.001	− 0.219	− 0.36|− 0.08	0.002
PAEE	0.246	0.10|0.39	0.001	0.283	0.14|0.43	< 0.001	0.201	0.06|0.35	0.007	0.240	0.10|0.38	0.001	− 0.163	− 0.31|− 0.02	0.027
CRF	0.279	0.14|0.42	< 0.001	0.320	0.18|0.46	< 0.001	0.214	0.07|0.36	0.004	0.278	0.14|0.42	< 0.001	− 0.209	− 0.35|− 0.07	0.005

Values are standardized regression coefficients (β), 95% confidence intervals (CI), and p values from linear regression analyses in which each ST, PA, and CRF variable was entered individually with years from peak height velocity into the models. P values < 0.05 indicating statistically significant associations are in bold

ST sedentary time, PA physical activity, CRF cardiorespiratory fitness, SDNN standard deviation of all RR intervals, RMSSD root mean square of successive RR interval differences, LF low-frequency power, HF high-frequency power, LPA light PA, MPA moderate PA, VPA vigorous PA, MVPA moderate-to-vigorous PA, PAEE physical activity energy expenditure