Effect of breathing exercises on blood pressure and heart rate: A systematic review and meta-analysis

Abstract

Background

Breathing exercises have been reported to have positive physiological effects on the body. The incidence of hypertension has become a major risk factor for cardiac complications leading to higher morbidity and mortality. Our aim was to conduct a systematic review and meta-analysis to study the effect of breathing exercises on blood pressure (BP) and heart rate (HR).

Methods

A systematic review and meta-analysis analyzing randomized clinical trials (RCTs) about the effect of breathing exercises on blood pressure was conducted (PROSPERO Registration ID: CRD42022316413). PubMed, ScienceDirect, WebofScience, and Cochrane Library databases were screened for RCTs from January 2017 to September 2022. The main search terms included “breathing exercise”, “Pranayam”, “Bhramari”, “alternate nostril breathing”, “deep breathing”, “slow breathing”, “hypertension”, and “high blood pressure”. The primary outcome was the value of the systolic blood pressure and diastolic blood pressure after the intervention. The effect on heart rate was also analyzed as a secondary outcome.

Results

A total of 15 studies were included in the meta-analysis. Breathing exercises have a modest but significant effect on decreasing systolic blood pressure (−7.06 [-10.20, −3.92], P = <0.01) and diastolic blood pressure (−3.43 [-4.89, −1.97], P = <0.01) mm Hg. Additionally, breathing exercises were also observed to cause a significant decrease in the heart rate (−2.41 [-4.53, −0.30], P = 0.03) beats/minute.

Conclusion

In a comprehensive systematic review and meta-analysis of breathing exercises and its effect on BP and HR, there is a moderate but significant positive effect. The studies are not deprived of bias.

1. Introduction

Hypertension (HTN) is one of the most common causes of morbidity and mortality in developed countries. Currently, there are approximately one billion people suffering from HTN and it has been estimated that this figure might increase to 1.5 billion by 2025.1 According to the American Heart Association (AHA), HTN is defined as systolic blood pressure (SBP) > 140 mmHg and diastolic blood pressure (DBP) > 90 mmHg.2 As per the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure, HTN is the most prevalent risk factor for cardiovascular diseases.3 Uncontrolled HTN may lead to various cardiovascular complications including stroke, aneurysm, myocardial infarction, and heart failure.4.

There is a strong correlation between blood pressure (BP) and adverse cardiovascular outcome and it is reported that even a small decrease of 5 mmHg BP in hypertensive patients can lead to an approximate 25 % decrease in cardiovascular complications.5 In the United States, around 75 % of hypertensive patients take medications to control their BP.6 The cost of anti-hypertensive drugs, and the burden on hospitalizations due to drug interaction, non-adherence, and complications add to 100–300 billion dollars per year.7 There are myriad medications that are available to control BP but only a few are utilized because of cost limitations, compliance issues, and adverse effects. The proven first-line therapy for HTN still remains a change in lifestyle including exercise, weight loss, and low sodium diet (DASH diet).8.

As per the 2015 National Health Statistics report, complementary and alternative medicine (CAM) is being used by approximately 33.2 % of the patients, in addition to medications.9 One of the non-pharmacological methods is device-guided breathing, which is recommended by the AHA to control BP,[10], [11], [12] but the high cost of the device is a limitation for its use. However, Hateren et al.13 and Landman et al.14 reported no short-term beneficial effect of device-guided breathing exercises on the reduction of BP among hypertensive patients.

Yoga is one of the forms of alternative therapy that is now being used to control hypertension, diabetes, and hypothyroidism, among many other co-morbidities. Yoga is an ancient tradition that incorporates asanas (postures), pranayama (breathing exercises), and dhyana (meditation).[15], [16], [17] Pranayam is made up of two words: ‘Prana’ and ‘Ayama’. Prana means ‘vital energy’ or ‘life force’ and Ayama means ‘expansion’. There are many kinds of breathing exercises like alternate nostril breathing (Nadi Suddhi), Sheetali Pranayama, Sheetkari pranayama, slow breathing, deep breathing, Kapalbati, Bhastrika, Bramari, Bahir Kumbhaka, Ujjayi pranayama, and others.

There are several studies examining the anti-hypertensive effect of Yoga.[18], [19], [20], [21] The effect of breathing exercises is not limited to controlling BP and HR but can also lead to an improvement in anxiety,22,23 depression,24 pain perception,25 chronic obstructive pulmonary disease,26 asthma,27 insomnia,28 stress,29 PTSD,30 and cancer.31 Although multiple studies have reported a positive effect of breathing exercises on reducing BP [[32], [33], [34]] and HR,32 there is no pooled data concluding this individual component of yoga leads to a decrease in BP and HR. Also, the degree to which breathing exercises can decrease BP and HR remains unclear.

To address this gap, this is the first systematic review and meta-analysis of the RCTs studying the effect of various breathing exercises on blood pressure (SBP and DBP) and heart rate (HR).

2. Materials and methods

2.1. Data sources and literature search

This systematic review and meta-analysis of the effect of breathing exercises on BP was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The protocol was registered on PROSPERO (Registration ID: CRD42022316413).

A thorough literature search was performed on PubMed, ScienceDirect, Cochrane library, and Web of Science for relevant articles from January 2017 to September 2022. Our search strategy included keywords such as “Breathing exercise*” OR “Pranayam*” OR “Bhramari” OR “Alternate nostril breathing” OR “Deep breathing” OR “Slow breathing” OR “Slow breathing” with “Hypertension” OR “High blood pressure”, while “pulmonary hypertension” was excluded. The detailed inclusion and exclusion criteria are stated below.

2.2. Inclusion and exclusion criteria

Inclusion criteria

• •Studies reporting the effect of breathing exercises on BP,
• •Peer-reviewed, English language articles (randomized clinical trials [RCT], cohort studies, case series),
• •Studies reporting the pre-and post-intervention BP,
• •Studies having a control group (non-intervention group),
• •Studies published between January 2017 and September 2022,
• •Studies including only adult subjects ≥18 years of age.

Exclusion criteria

• •Non-English language manuscripts,
• •Studies not reporting BP as an outcome,
• •Other literature (systematics reviews, meta-analysis, book chapters, conferences, case reports, posters),
• •Abstracts only were excluded because of a lack of methodology and outcomes,
• •Non-human studies.

2.3. Data extraction

The relevant articles from the selected databases were exported to the ‘Rayyan’ screening and data extraction web tool. The first step was to identify and eliminate the duplicates from all the retrieved articles. Each article was initially screened by two investigators (PG, AM) based on the title and abstracts, followed by full-text screening of selected articles to check for their relevance. References of the short-listed articles were also screened for additional studies. All disagreements were resolved with discussions between the two authors, or with input from a third independent author reviewer. The articles that did not meet the inclusion criteria were discarded from the study. The following data was extracted by investigators in duplication to Microsoft Excel from each paper: average SBP, DBP, HR before and after the intervention with standard deviation, type of intervention (breathing exercise), number of participants in control and case group, any adverse effects and location of the study performed along with the demographic details. Effect on SBP and DBP were the primary outcomes studied. The HR was the secondary outcome of interest. For the eligible studies in which the BP values were not present, the corresponding authors were emailed in order to provide the data.

2.4. Risk of bias

Cochrane Risk of Bias Tool 35 was used to determine the risk of bias in each study independently by two authors and disagreements were resolved by discussion to achieve a final decision. Each study was assessed based on the following domains: sequence generation, allocation concealment, blinding participants and personnel, blinding outcome assessors, incomplete outcome data, selective reporting and other bias (rating-low risk, high risk, unclear risk). Any discrepancies between the authors were resolved by a third reviewer through discussion.

2.5. Data analysis

All the data was analyzed by Review Manager (RevMan) Version 5.1 from the Cochrane Collaboration 36 and the forest plots were constructed with P = 0.05 as a cut-off point for removal. P < 0.05. (P < 0.10 for heterogeneity) was considered statistically significant. Subgroup analysis was conducted to investigate the sources of heterogeneity and to identify subgroups of patients who are more likely to benefit from the intervention. If the effect sizes are different between the subgroups, this suggests that the characteristic is moderating the effect of the intervention. Publication bias was assessed by visually inspecting funnel plots and employing Egger's regression test. Visual inspection of the funnel plot aimed to identify any asymmetry, while Egger's regression test evaluated the intercept of the funnel plot. A significant intercept in Egger's regression test suggests that the observed effect size is larger than the true effect size, indicating the presence of publication bias.

3. Results

3.1. Literature search

A total of 915 articles matched the inclusion criteria during the initial database search on PubMed, Cochrane library, ScienceDirect, and Web of Science. Of these, 89 articles were not retrieved. From the remaining 826 articles, 458 duplicates and book chapters were identified which were removed before the screening. The remaining 368 articles were screened by two authors independently and 287 articles were excluded due to a lack of relevant discussion in the title and abstract. Out of this, a total of 81 articles were sought for full-text review. Eventually, 15 articles that met the eligibility criteria were included and 66 articles were excluded (Fig. 1).

Fig. 1.

PRISMA flow diagram.

3.2. Study characteristics

The 15 included articles were published between January 2017 and September 2022. These articles were from several countries i.e., India (n = 6), Brazil (n = 2), Thailand (n = 1), Poland (n = 1), China (n = 1), USA (n = 1), Nepal (n = 1), Malaysia (n = 1) and Columbia (n = 1). These studies included a mean (±SD) of 75 ± 45 participants ranging from 21 to 170 (Table 1). There were a total of 1097 participants from all the included studies, with n = 586 (53 %) in the study group (practicing breathing exercise) and n = 511 (47 %) in the control group. The baseline characteristics in the study were similar between the case and control group (Table 2) [[37], [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50]]. Around 89 % completed the study in the breathing group as compared to 94 % in the control group. On baseline, the participants in the breathing group had a BMI of 26.9 (±2.3) as compared to the control group with the BMI of 27.2 (±2.2). An average age of 54.8 (±8.9) years was noted in the breathing group as compared to 54.4 (±8.7) years in the control group. The baseline SBP and DBP in the breathing group were 139.8 ± 11.1 mmHg and 84.7 ± 8.6 mmHg respectively as compared to 136.4 ± 12.0 mmHg and 83.7 ± 6.6 mmHg respectively in the control group. A baseline HR of 75.7 ± 7.9 bpm was noted in the breathing group as compared to 76.0 ± 7.7 bpm in the control group. The studies had 11 different types of breathing exercises i.e., slow loaded breathing (n = 7), Sheetali, Sheetkari Pranayam (n = 2), deep-breathing, alternate nostril breathing, yogic breathing, Ujjayi breathing, Bee-humming, Buteyko & Bhramari pranayam. The length of studies ranged from a single session to multiple sessions up to 90 days, and the duration of the breathing exercises ranged from 10 min to 75-min sessions (Table 1, Table 2). The breathing group was supervised in a total of 9 studies and was not supervised in six studies (Table 3). shows the characteristics of each included study. Fig. 2, Fig. 3, Fig. 4 shows the baseline characteristic difference in the SBP, DBP and HR in the case and control groups respectively.

Table 1.

Demographic details of studies included.

Study details				Age (Case group)		Age (Control group)		Gender (Study group) ratio	Gender (Control group) ratio
S.no.	Author/Date	Country	Type of breathing exercise studied	Mean	SD	Mean	SD	M:F	M:F
1	De Barros et al., 2017	Brazil	Device guided slow breathing	49	9	52	11	47	23/73
2	Shetty et al., 2017	India	Sheetali and Sheetkari pranayamas	–	–	–	–		–
3	Li et al., 2017	China	Slow breathing	54.08	5.18	53.6	4.83	30	30/30
4	Kow et al., 2018	Malaysia	Music guided breathing	62.6	9.6	59.7	9.6	57.1:42.9	48.9:51.1
5	Ublosakka- Jones et al., 2018	Thailand	Slow loaded breathing training	66.4	4.2	68.2	4.8	1/8	8/8
6	Kalaivani et al., 2019	India	alternate nostril breathing exercise	–	–	–	–	31/54	39/46
7	Lachowska et al., 2019	Poland	device-guided SLOWB	52	17	52	17	16 (76 %)	16 (76 %)
8	Misra et al., 2019	Columbia	Yogic breathing exercises	61.6	11.3	58.6	12	54:46:00	46:54:00
9	Srinivasan et al., 2019	India	Slow breathing (4 s inspiration and 6 s expiration)	45.1	8.25	42.2	9.23	65/35	60/40
10	Fetter et al., 2020	Brazil	Ujjayi pranayam	59	1.1	58	1.2	14	All Females
11	Ghati et al., 2021	India	Bee-humming exercise	49.59	7.88	48.25	8.45	53:47:00	54:46:00
12	Sathe et al., 2020	India	Buteyko breathing and bhramari group	60.57	8.96	59.71	8.95	11	11:10
13	Thanalakshmi et al., 2020	India	Sheetali pranayama	37.8	12.21	39.2	10.8	28/12	29/11
14	Dhungana et al., 2021	Nepal	Pranayam	47.1	11	48.4	10.7	42.6:57.4	61.6:38.3
15	Craighead et al., 2021	USA	high‐resistance Inspiratory muscle strength training (IMST)	67	2	67	2	8	9:09

Table 2.

Characteristics of studies included.

S.no.	Author/Location/Date	Sample size (breathing, control)	% completed (breathing, Control)	Study population	Breathing exercise intervention (study group)	Breathing exercise frequency/duration of session	Adverse events
1	De Barros et al.37, 2017, Brazil	22,19	77, 78	Hypertensive adults (>18years), both-genders, with or without treatment, without any comorbidities	Device-guided slow breathing (DGB)	15 min/day - 4 weeks	Nil
2	Shetty et al.4, 2017, India	30,30	100,100	Hypertensive adults of age between 25 and 65 years on regular medication, without any comorbidities	Sheetali and Sheetkari Pranayama	20 min/day - 30 days	Nil
3	Li et al.38, 2017, China	60,60	100,100	Hypertensive patients without any regular medication use, and co-morbid condition	Slow Breathing	One session −16 min	Nil
4	Kow et al.39, 2018, Malaysia	42,45	92,97	Adult patients with Stage I hypertension diagnosed at least 6 months back, with/without medications and without any co-morbid condition	Music guided deep breathing exercise	15 min/day - 8 weeks	Nil
5	Ublosakka- Jones et al.40, 2018, Thailand	16,16	100,100	Old Adults between the age of 60–80 years, with controlled isolated systolic hypertension, without any comorbid condition	Slow guided breathing	10 min/day - 8 weeks	Nil
6	Kalaivani et al.41, 2019, India	85,85	100,100	Hypertensive adults between the age of 30 and 60 years on regular medications	Alternate nostril breathing	20 min/day - 5 days	Nil
7	Lachowska et al.42, 2019, Poland	11,10	100,80	Adults, >18 years of age, with HFeEF on optimal medical management	Device- guided slow breathing	30 min/day - 3 months	Nil
8	Misra et al.43, 2019, Columbia	101,32	60,69	Adults with uncontrolled hypertension, regardless of pharmacological therapy, without any comorbid condition, 52 % male, mean age of 61 years	Yogic breathing exercise	15 min/day - 6 weeks (5 times a week)	Nil
9	Srinivasan et al.44, 2019, India	20,20	100,100	Adults with pre and stage I hypertension between the age of 30 and 60 years, including both genders, with no comorbidities	Slow breathing (4 s inspiration and 6 s expiration)	One session - 30 min	Nil
10	Fetter et al.45, 2020, Brazil	14,10	100,100	Females between the age of 45 and 68 years, with a blood pressure of >140/90 mmHg, on medication (CCB), without any comorbidities	Ujjayi breathing	75-min session, twice a week - 12 weeks	Nil
11	Ghati et al., 46 2021, India	35,35	91,100	Adults from 30 to 70 years of age, with blood pressure >140 and > 90, including both genders, on medication, without any comorbidities	Bee-humming exercise	1 session	Nil
12	Sathe et al.47, 2020, India	21,21	100,100	Adults with age >40 years with hypertension from the past 20 years, with a history of CAD, on medications	Buteyko and bhramari pranayam	6 cycles/day -one month	nil
13	Thanalakshmi et al.48, 2020, India	50,50	80,84	Adults with primary hypertension from age 18–60 years including both genders, without any comorbidities	Sheetali Pranayama	30 min session - 90 days	Nil
14	Dhungana et al.49, 2021, Nepal	61,60	96, 98	Adults with stage 1 hypertension including both genders, taking anti-hypertensive medications without any comorbidities	Pranayam	30 min/day for 5 days a week - 90 days	Nil
15	Craighead et al.50, 2021, USA	18,18	83, 77	Men and postmenopausal women with systolic BP more than 120 mmHg, without any co-morbidities	High‐resistance Inspiratory muscle strength training (IMST)	6 days per week - 6 weeks	Nil

Table 3.

Supervision of subjects in the studies included.

Author/Location/Date	Supervised or not	Ways to ensure compliance	Comments
De Barros et al., 2017	No	ABPM (Ambulatory blood pressure monitoring) using Mobil-O-Graph NG device (IEM, Germany) was used to monitor blood pressure remotely
Shetty et al., 2017	Yes
Li et al., 2017	Yes
Kow et al., 2018	No	Asked them to record the time and duration of their practice in a record book given to them	The authors also report that the lack of supervision may affect the quality of the breathing exercise and compliance for the same
Ublosakka- Jones et al., 2018	No	Subjects were given a checklist on which they recorded the time and duration of the exercise and heart rate and blood pressure after the exercise.	Contacted via telephone once a week and were encouraged to do the exercise. The subjects were asked to record the details of their session like time, duration and any side effects.
Kalaivani et al., 2019	Yes
Lachowska et al., 2019	No	Used a RESPeRATE device	They were called weekly via a trainer and obtained various information about the time, duration and vital parameters from the device.
Misra et al., 2019	No	The subjects logged their time and duration of the exercise and submitted their logs once a week.
Srinivasan et al., 2019	Yes
Fetter et al., 2020	Yes
Ghati et al., 2021	Yes
Sathe et al., 2020	No	No mention of compliance
Thanalakshmi et al., 2020	Yes
Dhungana et al., 2021	Yes
Craighead et al., 2021	Yes

Fig. 2.

Characteristics baseline SBP.

Fig. 3.

Characteristics baseline DBP

Fig. 4.

Characteristics baseline heart rate.

3.3. Effects of breathing exercise on BP and HR

Breathing exercises lead to a significant reduction of SBP in the intervention group (−12.24 [−21.99, −2.48], p < 0.001) as compared to a non-significant reduction of SBP in the control group (−3.02 [−15.82, 9.78]) as shown by the forest plots in Fig. 5, Fig. 6. The reduction of DBP in the intervention group was −4.93 [−6.91, −2.96], p < 0.001 whereas the reduction was negligible in the control group (−0.50 [−2.42, 1.41]) as shown in Fig. 7, Fig. 8. The effect of breathing exercises on HR in the intervention group was also found to be statistically significant i.e., (−3.16 [−5.11, −1.20], p= <0.001) whereas the effect of breathing exercise in control group was −1.22 [−2.60, 0.16] as shown by the forest plot in Fig. 9, Fig. 10 respectively. However clinical significance of difference of 3.2 beats/min would be up for debate. There is a substantial heterogeneity present among all the included papers: Tau2 = 28.98; Chi2 = 141.10, df = 14, (p < 0.001), I2 = 90 % for SBP and Tau2 = 5.11; Chi2 = 55.01, df = 12, (p < 0.001), I2 = 78 % for DBP. We conducted subgroup analysis based on country of origin where trial was conducted. The effect size is then calculated for each subgroup. Thus, different effect sizes across the subgroups indicate that the country of origin may be a moderating factor (Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10).

Fig. 5.

SBP variation in intervention group.

Fig. 6.

SBP variation in control group.

Fig. 7.

Dbp variation in intervention group.

Fig. 8.

Dbp variation in control group.

Fig. 9.

Heart rate variation in intervention group.

Fig. 10.

Heart rate variation in control group.

3.4. Risk of bias

All 15 studies which were included in the review have an unclear or high risk of bias. E-Table 1 shows the assessment of the risk of bias of the included study based on the Cochrane Risk of Bias Tool. Assessment of publication bias was performed using visual inspection of funnel plots and Egger's regression test, as presented in supplemental e-Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9. Detailed descriptions of the funnel plots, Egger regression test results, and respective interpretations of publication bias are also provided in the supplemental figures (e-Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9).

4. Discussion

The current systematic review and meta-analysis of 15 studies from 2017 to September 2022 provides a comprehensive assessment of the effect of breathing exercises on BP and HR. It indicated a positive effect of breathing exercises on SBP and DBP among adult subjects. Breathing exercises also showed an association with reduction in the HR, which was analyzed as a secondary outcome of our study.

Breathing exercises are a component of yoga practice. A systematic review and meta-analysis performed by Haggins et al.51 showed a significant effect of yoga, including pranayama/breathing exercises, on the reduction of SBP by 8.17 mmHg and DBP by 6.14 mmHg as compared to control group. Similarly, a recent meta-analysis by Wu et al.19 showed that regular practice of yoga and breathing exercises about three times a week decreased the SBP by 11 mmHg and DBP by 6 mmHg in the hypertensive group. Wu et al.19 also reported that the reduction in SBP was more pronounced in patients performing breathing exercises (∼8 mmHg) as compared to those not performing any breathing exercise (∼2 mmHg). However, both these studies considered other components of Yoga and other exercises, which may have led to a confounding bias towards the outcome. Comparatively, a reduction of 6 mmHg in SBP and 3 mmHg in DBP was reported in the breathing group as compared to the control group in our study.

Our findings were in concordance with Cramer et al.52 who also reported a decrease of 6.56 mmHg in SBP and 3.42 mmHg in DBP in the RCTs that excluded physical postures as compared to a decrease of 10.43 mmHg in SBP and 8.20 mmHg in DBP in the RCTs that included yoga physical postures. Whereas a study by Goncalves et al.53 which specifically focused on the effect of slow breathing exercises on BP, showed no significant reduction in the BP. However, they did not take into consideration other types of breathing exercises. Our study, on the other hand, included different types of breathing exercises to assess their effect on BP and found a significant reduction in SBP with various breathing exercises. Contradictory to these, Nivethitha et al.54 showed that there was an increase in BP after doing Bahir Kumbhaka (external breath retention), a type of breathing exercise. In this study, the increase in BP was expected as it was measured just after the exercise. A desirable effect could have been appreciated if it would have been practiced regularly for a sufficient amount of time, rather than just once as it was performed in this study.54 Ananda et al.55 showed a significant decrease in SBP, pulse pressure, and HR after practicing breathing exercises for 30 days regularly. Similarly, Naik et al.32 also showed a significant decrease in SBP, DBP, and HR after 12 weeks of regular practice of slow breathing exercises.

In patients with HTN, it is hypothesized that there is an increase in sympathetic activity. It is reported to be due to the following reasons: increased sympathetic innervation,56 lower sensitivity of the baroreceptor,57 higher sensitivity of carotid chemoreceptor, 58 changes with noradrenergic transmission and uptake,56, 59 and increased pulmonary vascular pressure. 59,60 Slow and deep breathing exercise decrease respiration rate, thus causing increased inhalation and exhalation volume, which eventually leads to an increased amount of oxygen entering into the bloodstream.61 Multiple studies have shown that breathing exercises, especially those involving deep breathing, can help in arteriolar dilatation as they inhibit sympathetic nervous system activity and activate cardiopulmonary mechanoreceptors which ultimately leads to a decrease in both SBP and DBP in hypertensive patients. [[62], [63], [64]] Our meta-analysis supports these findings by reporting a reduction in both SBP and DBP in patients performing breathing exercises when compared to control group.

Breathing exercises have been found to significantly increase HR variability in pre-hypertensive as well as hypertensive population due to an increase in baroreflex sensitivity.11,63 These exercises tend to cause a state of relaxation which slows down the HR and that has been linked to a decrease in SBP as well.65 Our study found similar association between breathing exercises and HR depicted by post-intervention decrease in HR by ∼2.5 beats per minute.

The proven and documented effect of breathing exercises was shown to be comparable to the reduction of BP reported due to other non-pharmacological modalities like reduction in salt intake, and exercise in a study by Soudarssanane et al.66 Our meta-analysis shows a reduction in SBP, DBP, and HR after doing breathing exercises, thus supporting the use of breathing exercises as an alternative way to control BP. Other reasons to support its use include, accessibility, enjoyability, low/no cost, and ease of practice. This leads to an increase in compliance and helps in maintaining the overall physical, and mental wellbeing.40.

This is the first systematic review and meta-analysis to study the effects of various breathing exercises on BP and HR. Strengths of this study include a thorough literature search using multiple databases, a duplicate review of the included articles, a systematic analysis of the data using standardized PRISMA checklist, and a quality assessment of the risk of bias in each study.

However, our study has its limitations. There were several different types of breathing exercises that were included, thereby decreasing the specificity of the exercise that leads to the most decrease in BP. The effect of breathing exercises could have been influenced by many other factors like meditation, diet, aerobic exercise, stress levels, and/or medications, which our study could not take into consideration. Also, the information on the duration of interventions in the included studies was very limited, therefore a knowledge gap exists about the extent of the long-term effect of breathing exercises on BP. We could not report the intensity and accuracy with which the participants performed their breathing exercises which could have also affected their BP. Other limitations of our study are that it included articles only in the English language, and some of the included studies had a small sample size.

5. Conclusion

Our systematic review and meta-analysis suggest that breathing exercises have positive effect on decreasing the blood pressure and heart rate. It is a safe practice that does not require any equipment. It could be an important adjunct non-pharmacological modality to control hypertension. Additional RCTs of longer duration and larger sample size are required to further confirm the extent to which breathing exercises impact the reduction in blood pressure and heart rate.

CRediT authorship contribution statement

Piyush Garg: Conceptualization, Data curation, Investigation, Methodology, Supervision, Validation, Visualization, Writing - original draft, Writing - review & editing. Ayushi Mendiratta: Data curation, Supervision, Writing - original draft, Writing - review & editing. Akshat Banga: Conceptualization, Investigation, Methodology, Project administration, Validation, Writing - original draft, Writing - review & editing. Anna Bucharles: Data curation, Resources, Supervision, Writing - original draft. Piccoli Victoria: Data curation, Investigation, Methodology, Writing - original draft. Balakrishnan Kamaraj: Conceptualization, Data curation, Writing - original draft. Rakhtan K. Qasba: Data curation, Investigation, Writing - original draft. Vikas Bansal: Data curation, Formal analysis, Investigation, Software, Supervision, Writing - original draft, Writing - review & editing. Jayaraman Thimmapuram: Supervision, Writing - original draft, Writing - review & editing. Robert Pargament: Supervision, Writing - original draft, Writing - review & editing. Rahul Kashyap: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing - original draft.

Handling Editor: Dr D Levy

Appendix A. Supplementary data

The following is/are the supplementary data to this article: