Table 3.

Singular versus inter-relation model comparisons.

HRV	Cortisol	Singular models HRV			Singular models cortisol			Inter-relation models					Model comparison
		βhrv	F	R2	βcort	F	R2	βcort	βhrv	βint	F	R2	ΔFb	ΔR2
LF		−.01	4.22	.18	–	–	–	–	–	–	–	–	–	–
	AUCAG	–	–	–	.17*	4.82	.20	−.21	−.54**	.67**	4.96	.25	4.72*	.04
	AUCI	–	–	–	.08	4.23	.18	.07	−.03	.08	3.86	.20	0.15	.00
	SlopeMax a	–	–	–	.15	4.52	.21	.27	−.56**	−.24	4.81	.26	5.56**	.04
	Maximum	–	–	–	.19*	4.96	.21	−.17	−.49**	.63**	5.05	.25	3.76*	.03
HF		−.05	4.29	.19	–	–	–	–	–	–	–	–	–	–
	AUCAG	–	–	–	–	–	–	.08	−.23	.19	4.10	.21	0.94	.01
	AUCI	–	–	–	–	–	–	.21	−.04	−.07	3.95	.21	0.54	.00
	SlopeMax a	–	–	–	–	–	–	.17	−.17	.01	3.72	.23	0.39	.00
	Maximum	–	–	–	–	–	–	.16	−.15	.08	4.34	.22	0.74	.01
LF/HF ratio		.01	4.22	.18	–	–	–	–	–	–	–	–	–	–
	AUCAG	–	–	–	–	–	–	−.10	−.23	.37	4.15	.22	1.19	.01
	AUCI	–	–	–	–	–	–	−.33	−.12	.52*	4.50	.23	2.96*	.04
	SlopeMax a	–	–	–	–	–	–	.82	−.02	−.79	3.93	.24	1.12	.01
	Maximum	–	–	–	–	–	–	−.22	−0.39±	.59*	4.79	.24	2.65±	.02

Note: All analyses controlled for age, sex, BMI Z-score, adrenarche, parental education, household income, sleep duration, & wake-time. β_cort = standardized beta coefficient for cortisol measure. β_hrv = standardized beta coefficient for HRV measure. β_int = standardized beta coefficient for interaction term. AUC_AG = area under curve relative to ground. AUC_I = area under curve relative to increase. Slope_Max = diurnal slope anchored to max sample using regression. LF = low frequency. HF = high frequency. Bold values indicate significance:

^±p < .07

^*p < .05

^**p < .01.

^aAnalyses also controlled for maximum cortisol sample, anchor point for calculation of Slope_Max.

^bChange in F test-statistic conservatively based on higher F test-statistic of either singular model.