Table 4.

Pairwise Contrasts Between Baseline, 4-2-4, and 5-5 Breathing Stages

Variable	Stage	Comparison Stage	Mean Difference (Stage -Comparison)	S.E.	p±
HF-HRV	Baseline	4-2-4	−0.33	0.13	.016
	Baseline	5-5	0.04	0.18	.843
	4-2-4	5-5	0.36	0.12	.006
BPM	Baseline	4-2-4	3.79	0.64	< .001
	Baseline	5-5	8.78	0.55	< .001
	4-2-4	5-5	0.08	0.17	.64
HR	Baseline	4-2-4	3.79	0.64	< .001
	Baseline	5-5	2.14	0.67	< .001
	4-2-4	5-5	−1.65	0.28	< .001
RMSSD	Baseline	4-2-4	−12.90	2.91	< .001
	Baseline	5-5	−12.70	4.02	.004
	4-2-4	5-5	0.20	2.87	.945
SDNN	Baseline	4-2-4	−33.58	4.35	< .001
	Baseline	5-5	−37.00	5.08	< .001
	4-2-4	5-5	−3.42	2.47	.175
LF-HRV	Baseline	4-2-4	−4773.52	823.16	< .001
	Baseline	5-5	−5547.25	1005.39	< .001
	4-2-4	5-5	−773.73	385.10	.03
IBI	Baseline	4-2-4	−40.60	7.89	< .001
	Baseline	5-5	−19.47	8.14	.023
	4-2-4	5-5	21.13	3.73	< .001
ARA	Baseline	4-2-4	−9.10	3.31	.03
	Baseline	5-5	−20.98	5.16	< .001
	4-2-4	5-5	−11.88	2.68	< .001

Note:

^±Using the Holm-Bonferroni correction for multiple comparisons, only p-values smaller than .011 are considered significant and are bolded. Pairwise contrasts were used to investigate between stage differences. High frequency heart rate variability (HF-HRV). Respiration rate was measured in breaths-per-minute (BPM). Heart rate measured as the number of beats in 60 seconds (HR). Root mean squared of the successive differences between adjacent N-to-N peaks measured in ms (RMSSD). Standard deviation in N-to-N interval measured in ms (SDNN). Low frequency heart rate variability measured in ms² (LF-HRV). Low frequency to high frequency ratio measured in ms² (LF/HF Ratio). Very low frequency heart rate variability measured in ms² (VLF-HRV). The number of interval differences of successive N to N intervals or heartbeat intervals greater than 50ms divided by the total number of NN intervals yielding a percentage (pNN50). Inter-beat-interval measured in ms (IBI). Abdominal Respiration Amplitude measured in volts (ARA).