. 2023 Jan 25;14:1048338. doi: 10.3389/fphys.2023.1048338

TABLE 4.

Characteristics and outcomes of included studies.

No	Author	Title	Population characteristics	Study design	Sample	Age, gender	Outcome
1.	Jones et al. (2010)	An Inspiratory load enhances the antihypertensive effects of home-based training with slow deep breathing: a randomized trial	Inclusion criteria	RCT	30	35–65 years; male and female	- SBP
			- Essential hypertension Stage I or II				- DBP
			- good communication				- PP
			- independent ambulation				- MAP
			Exclusion criteria
			- secondary hypertension
			- respiratory disease
			- diabetes mellitus
			- cardiac, renal, or cerebrovascular disease
			- dyslipidemia
			- pregnancy within the last 6 months
2.	Lin et al. (2012)	Heart Rate Variability Biofeedback Decreases	asymptomatic prehypertension	RCT	43	mean age: 22, 3 years, male and female	- HRV
		Blood Pressure in Prehypertensive Subjects by Improving Autonomic Function and Baroreflex					- BP
							- BRS
3.	de Barros et al. (2017)	Effects of long term device-guided slow breathing on sympathetic nervous activity in hypertensive patients: a randomized open-label clinical trial	The inclusions criteria were	RCT	20	- Both genders ≥18 years old,-	- sympathetic nerve activity (SNA) measured
			- with or without pharmacological treatment				- plasma catecholamines
			- mean 24-h BP by ABPM above the normal range				- BP
			- SBP ≥130 mmHg and/or DBP ≥80 mmHg
			Exclusion criteria were
			- in use of beta-blockers or centrally acting sympatholytic agents
			- 3 or more antihypertensive drugs
			- secondary hypertension, chronic respiratory disease, diabetes mellitus, a chronic renal disease defined as estimated glomerular filtration rate (eGFR) by the equation MDRD Study<60 ml/min, coronary artery disease, congestive heart failure
			- pregnant women
			- patients with a BMI >30 kg/m2
4.	Wang et al. (2021)	Long-Term Effect of Device-Guided Slow	Essential hypertension patients	Prospective observational study	- 46	- 35–75 years	- BP
		Breathing on Blood Pressure Regulation and Chronic Inflammation in Patients with Essential	Inclusion criteria: patients who received medications and had good lifestyle control			- Male and female	- HRV
		Hypertension Using a Wearable ECG Device	Exclusion criteria
			1. Recent medication titration related to BP or ANS function within 2 weeks
			2. Recent major surgery or admission within 1 year
			3. Had a history of anemia, asthma, thyroid dysfunction or autonomic neuropathy, or 4. Lived at high altitudes or had recently visited high mountainous areas for more than 1 week
5.	Hering et al. (2013)	Effects of acute and long-term slow breathing exercise	- Men with newly diagnosed essential hypertension	RCT	- 28	- 37 ± 4.0 years, Male	- BP
		On muscle sympathetic nerve activity in untreated male patients with hypertension	- Office SBP between 140 and 160 mmHg and DBP lower than 95 mmHg				- HR
							- MSNA
6.	Wang et al. (2010)	Effect of Slow Abdominal Breathing Combined with Biofeedback on Blood Pressure and Heart Rate Variability in Prehypertension	prehypertension postmenopausal women	RCT	- 22	- ages 45–60 years	- BP
6.	Wang et al. (2010)		prehypertension postmenopausal women	RCT	- 22	Female	- HRV
7.	Mitsungnern et al. (2021)	The effect of pursed-lip breathing combined with number counting on blood pressure and heart rate in hypertensive urgency patients: A randomized controlled trial	Inclusion criteria: HT urgency	RCT	110	- aged 18–80 years old male ad female	BP
			Exclusion criteria
			- cardiac arrhythmias, acute HF, acute coronary syndrome (ACS), acute stroke, acute respiratory failure
			- alteration of consciousness
			- pregnancy
8.	Anderson et al. (2010)	Regular Slow Breathing exercises effects on Blood pressure and breathing patterns at rest	Prehypertension/Mild hypertension	RCT	40	53.4 ± 2.8	BP
			Inclusion criteria: mean systolic BP of the 10 measurements during the two sessions was >130 mmHg and <160 mmHg and mean diastolic BP < 100 mmHg				Breathing rate, tidal volume and minute ventilation
			Exclusion criteria
			1. Had respiratory, cardiovascular, & renal disease
			2. Were diabetes or the use of tobacco, steroids, hormone-replacement therapy, angiotensin II receptor blockers, angiotensin-converting enzyme inhibitors, b-blockers or, any other medications that would interfere with central nervous system activity
9.	Sangthong et al. (2016)	Breathing Training for Older Patients with Controlled Isolated Systolic Hypertension	Inclusion criteria were mild to moderate ISH and older than 60 yr with constant medication for at least 1 month before the study	prospective randomized controlled trial	30	older than 60 yr male and female	BP
			Exclusion criteria				HR
			- regularly exercised				PP
			- had active cardiovascular disease, stroke, chronic renal failure, or chronic respiratory disease
			- habitually taking supplements or herbal medicines that might affect blood pressure
10.	Jones et al. (2015)	Slow Breathing Training Reduces Resting Blood Pressure and the	Inclusion criteria	RCT	30	aged 35–65 years	the SBP response to handgrip exercise
		Pressure Responses to Exercise	- essential hypertension, stage I-II
			- an independent lifestyle
			Exclusion criteria were
			- blood pressure greater 180/110 mmHg or secondary hypertension
			- respiratory disease, diabetes mellitus, heart, renal or cerebrovascular disease, dyslipidemia
			- pregnancy within the last 6 months
11.	Ping et al. (2018)	The impact of music guided deep breathing exercises on blood pressure control - A participant blinded randomized controlled study	stage 1 essential hypertension diagnosed at least 6 months before study entry with or without antihypertensive medications	RCT	87	62.6 ± 9.6 Male and female	BP
			Inclusion criteria
			- should be stable on anti-hypertensive treatment for a minimum of 2 months before the study and - no change in medications during participation in the trial
			Exclusion criteria
			1. With impaired hearing, ischaemic heart disease, congestive heart failure, renal impairment
			2. Diabetes mellitus of suboptimal control (HbA1C > 7 mmol/L)
			3. Stroke within the previous 2 years
			4. Major organ failure
			5. Respiratory diseases
			6. Resulting in dyspnoea at rest and those who were unable to operate a CD player or did not have access to a CD player
12.	Li et al. (2018)	Effects of slow breathing rate on heart rate variability and arterial baroreflex sensitivity in essential hypertension	inclusion criteria	RCT	60	- 54.08 ± 5.18	- BP
			- Essential hypertension			- Male and female	- HRV
			- not taking any medication				- Arterial baroreflex sensitivity
			- non-smokers
			- none was involved in competitive sports activities
			Exclusion criteria
			- ischemic heart disease, congestive heart failure, chronic atrial fibrillation, renal failure
			- diabetes mellitus
			- previous stroke
			- major organ failure
			- respiratory diseases, psychiatric disorders, and hearing impairment
13.	Ublosakka-Jones et al. (2018)	Slow loaded breathing training improves blood pressure, lung capacity, and arm exercise endurance for older people with treated and stable isolated systolic hypertension	Inclusion criteria	RCT 8 weeks	66.4 ± 4.2	- 66.4 ± 4.2 male and female	- BP
			- with controlled mild to moderate ISH				- HR
			- being independently active and with good communication				- Maximal inspiratory pressure
			Exclusion criteria were				- Spirometry testing
			- secondary hypertension, use of beta-blockers				- Chest wall and abdominal expansion
			- heart or respiratory disease and arm exercise limited by pain				- Chest wall and abdominal expansion
14.	Kalaivani et al. (2019)	Effect of alternate nostril breathing exercise on blood pressure, heart rate, and rate pressure product among patients with hypertension in JIPMER, Puduccherry	- Inclusion criteria	RCT	- 170	- 51–60 years	- BP
			- Men and women 30 sd 60 years old			- Male ang female	- HR
			- patients diagnosed with mild and moderate hypertension taking antihypertensive medication
			- Exclusion criteria: have a previous experience of yoga and patients who were chronic smokers
15.	Oneda et al. (2010)	Sympathetic nerve activity is decreased during device-guided slow breathing	- Inclusion criteria	RCT	- 31	- 51 ± 9 years	- BP
			- Mild hypertesive			- Male and female	- HR
			- Non-diabetic, non-obese				- Respiratory Rate (RR)
			- receiving stable treatment for hypertension, with no changes 1 month before the experimental session				- MSNA
			- Exclusion criteria: Receive sympatholitics				- MSNA
16.	Ubolsakka-Jones et al. (2019)	The effects of slow loaded breathing training on exercise blood pressure in isolated systolic hypertension	Inclusion criteria	RCT	- 22	- 67 ± 6 years	- Resting BP (the end of 8 weeks training period, at 12 and 16 weeks after training)
			- age 60–80 years with stable controlled mild to moderate ISH, (average resting sBP >140 mmHg and dBP <90 mmHg)			- Male and female	- Resting HR
			- good communication, and independent living				- BP and HR exercise
			Exclusion criteria
			- secondary hypertension
			- use of beta-blockers
			- heart disease, respiratory disease, neuromuscular disease, arm exercise limited by pain
17.	Srinivasan and Rajkumar, (2019)	Effects of slow breathing on blood pressure and end tidal carbon dioxide in hypertension: randomised controlled trial	Inclusion criteria: pre- and stage I IHT (120–159 mmHg)/(80–99 mmHg), age range: 30–60 years and both the genders	RCT	- 40	45.10 ± 8.25 male and female	- BP
							- End tidal CO2
							- HR
18.	Modesti et al. (2010)	Psychological predictors of the antihypertensive effects of music guided slow breathing	Inclusion criteria	RCT	- 29	- 40–75 years	- BP
			- outpatients aged 40–75 years with essential hypertension, untreated or constantly treated with the same doses of antihypertensive drugs for at least 3 months prior to the study				- Quality of life
			Exclusion criteria				- Psychological subscale
			- chronic atrial fibrillation, angina, heart failure, cerebrovascular disease, diabetes mellitus, renal failure, asthma, chronic respiratory disease, pregnancy, neoplasia and altered night-time sleep because of shift work				- Psychological subscale
19.	Ubolsakka-Jones et al. (2017)	The effect of slow-loaded breathing training on the blood pressure response to handgrip exercise in patients with isolated systolic hypertension	Inclusion criteria	prospective randomized trial	- 30	- 60–70 years	- Resting BP and HR
			- mild-to-moderate ISH			- Male and female	- BP and HR followed by a static handgrip exercise test
			- over 60 years
			- constant medication for at least 1 month prior to the study
			Exclusion criteria
			- regularly exercised had active cardiovascular disease, stroke, chronic renal failure or chronic respiratory disease
20.	Adhana et al. (2013)	The influence of the 2:1 yogic breathing technique on essential hypertension	Inclusion criteria	RCT	- 30	- ages of 20–50 years	- EMG
			- Males and females between ages of 20–50 years			- male dan female	- GSR (Galvanic skin response)
			- newly diagnosed of having essential hypertension in prehypertensive stage and stage 1				- FTT (Finger tip temperature)
			- Not taking treatment				- HR
			- No past history of any chronic illness like chronic renal failure, uncontrolled diabetes mellitus				- RR
			Exclusion criteria				- BP
			- Significant co-morbidity like angina
			- uncontrolled diabetes mellitus, chronic renal failure, stroke, obesity

ABPM, Ambulatory blood pressure monitoring; ACS, Acute coronary syndrome; ANS, Autonomic nervous system; BMI, Body mass index; BP, Blood pressure; BRS, Baroreflex sensitivity; DBP, Diastolic blood pressure; FTT, Finger tip temperature; GSR, Galvanic skin response; HF, Hheart failure; HR, Heart rate; HRV, Heart rate variability; HT, Hypertension; ISH, Isolated systolic hypertension; MAP Mean arterial pressure; MSNA, Muscle sympathetic nerve activity; PP, Pulse pressure; RCT, Randomized control trial; RR, Respiratory rate; SBP, Systolic blood pressure; SNA, Sympathetic nerve activity.