Effects of long term device-guided slow breathing on sympathetic nervous activity in hypertensive patients: a randomized open-label clinical trial

Figures & data

Figure 1. Flowchart of subjects during the study.

Table 1. Demographic, clinical and laboratory characteristics: Device-Guided Slow Breathing (DGB) and control group (CG).

Variable (Mean ± SD or %)	DGB (n = 17)	GC (n = 15)	p
Age (years)	49 ± 9	52 ± 11	0.40
Gender Female (%)	47	73	0.16
Abdominal circumference (cm)	90 ± 9	91 ± 9	0.78
BMI (Kg/m^2 )	25.8 ± 3.0	27.1 ± 2.4	0.18
Hemoglobin (g/dL)	14.3 ± 1.3	13.9 ± 1.4	0.19
Total cholesterol (mg/dL)	207 ± 51	196 ± 30	0.14
HDL cholesterol (mg/dL)	60 ± 14	57 ± 12	0.48
LDL cholesterol (mg/dL)	124 ± 45	116 ± 25	0.18
Triglycerides (mg/dL)	124 ± 91	114 ± 49	0.50
Creatinine (mg/dL)	0.87 ± 0.17	0.89 ± 0.18	0.92
eGFR (ml/min)	93 ± 13	88 ± 18	0.42
Potassium (mEq/L)	4.3 ± 0.4	4.2 ± 0.5	0.89
Fasting blood glucose (mg/dL)	90 ± 14	86 ± 10	0.20
Glycated Hemoglobin(%)	5.5 ± 0.3	5.4 ± 0.3	0.28
Office SBP(mmHg)	134 ± 12	131 ± 9	0.68
Office DBP(mmHg)	87 ± 9	84 ± 9	0.31
Antihypertensive Therapy (Yes/No)	4/13	12/3	p < 0.01
Diuretic	3	2
CCB	0	3
ACEI	3	4
ARB	1	4

BMI: Body Mass Index; HDL: High-Density Lipoprotein.; LDL: Low Density Lipoprotein; eGFR: estiimated Glomerular Filtration Rate; SBP: Systolic Blood Pressure; DBP: Diastolic Blood Pressure; CCB: Calcium Channel Blocker; ACEI: Angiotensin Converting Enzyme Inhibitor; ARB: Angiotensin Receptor Blocker.

Table 2. Office and 24-hours blood pressure before and after the intervention: Device-Guided Slow Breathing (DGB) versus Control Group (CG).

	DGB (n = 17)		CG (n = 15)
Variable	Before	After	Before	After
SBP office (mmHg)	134 ± 12	134 ± 15	131 ± 9	133 ± 11
DBP office (mmHg)	87 ± 9	88 ± 12	84 ± 9	84 ± 6
SBP ABPM 24 hs (mmHg)	127 ± 8	130 ± 11	128 ± 8	126 ± 11
DBP ABPM 24 hs (mmHg)	88 ± 5	90 ± 7	89 ± 7	86 ± 8
SBP ABPM Awake (mmHg)	131 ± 8	134 ± 11	131 ± 10	128 ± 10#
DBP ABPM Awake (mmHg)	92 ± 5	94 ± 7	92 ± 9	88 ± 8#
SBP ABPM Sleep (mmHg)	118 ± 10	120 ± 12	122 ± 9	122 ± 15
DBP ABPM Sleep (mmHg)	78 ± 7	80 ± 9	82 ± 8	80 ± 10
HR 24 hours (bpm)	75 ± 7	78 ± 7*	77 ± 8	76 ± 9
HR awake (bpm)	80 ± 7	83 ± 8	81 ± 9	81 ± 9
HR sleep (bpm)	66 ± 8	70 ± 9*	68 ± 8	68 ± 9

SBP: Systolic Blood Pressure; DBP: Diastolic Blood Pressure; ABPM: Ambulatory Blood Pressure Monitoring; HR: Heart Rate.

* p < 0.05 vs DGB before.

# p < 0.05 vs CG before and DGB after.

Figure 2. Plasma norepinephrine concentration before and after intervention in the Control Group (CG) and Device-Guided Slow Breathing (DGB).

Figure 3. Muscular Sympathetic Nervous Activity (MSNA) measured by microneurography before and after intervention in the Control Group (CG) and Device-Guided Slow Breathing (DGB).

Table 3. Muscular Sympathetic Nervous Activity (MSNA) measured by microneurography before and after intervention: Device-Guided Slow Breathing (DGB) versus Control Group (CG).

	DGB (n = 10)			CG (n = 10)
Variable	Before	After	p	Before	After	p
Δ MSNA Isometric Handgrip (bursts/min)	3 ± 7	2 ± 3	0.52	2 ± 6	−1 ± 5	0.32
Δ MSNA Occlusion (bursts/min)	2 ± 6	3 ± 5	0.56	6 ± 14	−2 ± 5	0.09
Δ MSNA Recovery (bursts/min)	1 ± 5	2 ± 03	0.42	3 ± 5	−1 ± 6	0.13

MSNA: Muscular Sympathetic Nerve Activity.