. 2022 Aug 26;6(8):e37994. doi: 10.2196/37994

Table 2.

Pearson bivariate correlation statistics before and after the intervention between physiological measures of heart rate and heart rate variability recorded with participant age and level of ASD (autism spectrum disorder) symptoms as measured by the Social Communication Questionnaire [59].

			Age		ASD		HF-HRV^a		RMSSD^b	SDNN^c		HR^d
Age
	Before the intervention	1		–0.250		–0.580^e		–0.596^e		–0.548^e	–0.001
	After the intervention	—^f		—		–0.389		–0.381		–0.522^e	–0.062
ASD^g
	Before the intervention	—		1		–0.221		–0.134		–0.184	0.541^e
	After the intervention	—		—		–0.557^e		–0.442		–0.504^e	0.743^h
HF-HRV
	Before the intervention	—		—		1		0.929^h		0.902^h	–0.562^e
	After the intervention	—		—		—		0.892^h		0.905^h	–0.733^h
RMSSD
	Before the intervention	—		—		—		1		0.946^h	–0.514^e
	After the intervention	—		—		—		—		0.910^h	–0.616^e
SDNN
	Before the intervention	—		—		—		—		1	–0.465
	After the intervention	—		—		—		—		—	–0.694^h
HR
	Before the intervention	—		—		—		—		—	1
	After the intervention	—		—		—		—		—	—

^aHF-HRV: high-frequency heart rate variability (a frequency domain index that can indicate parasympathetic nervous system activity).

^bRMSSD: root mean square of successive differences in normal heartbeat contractions or interbeat intervals measured in milliseconds (a time domain heart rate variability index that can be associated with parasympathetic nervous system activity).

^cSDNN: SD of the normal heartbeat contractions; that is, normal-to-normal interbeat intervals measured in milliseconds.

^dHR: heart rate measured in beats per minute.

^eP<.05 (2-tailed).

^fNot applicable.

^gAutism spectrum disorder symptomatology measured using the Social Communication Questionnaire [59].

^hP<.01 (2-tailed).