Introduction
Pranayama, a form of breath regulation integral to the practice of Yoga, has garnered significant attention in both traditional and modern contexts. Rooted in ancient Indian philosophy, Pranayama is not merely a physical practice; it encapsulates a spiritual and psychological journey, fostering a profound connection between the body and mind. As contemporary research increasingly sheds light on its multifaceted benefits, it becomes essential to explore the scientific literature surrounding yogic breathing and its impact on various physiological systems. This essay aims to provide a comprehensive overview of the effects of Pranayama, drawing on an extensive review of published studies and highlighting the potential implications for health and wellness.
Methodology
To compile a thorough understanding of the subject, extensive searches were conducted across prominent databases, including PubMed, PubMed Central, and IndMed. The search utilized the keywords “Pranayama” and “Yogic Breathing,” yielding a total of 1400 references. This rich repository of literature encompasses experimental papers, case studies, and case series primarily in English, which collectively examine the effects of yogic breathing. By systematically analyzing this body of work, we uncover a preponderance of evidence that suggests beneficial effects of yogic breathing techniques, both in healthy individuals and in various clinical settings.
Physiological Benefits of Pranayama
The physiological implications of Pranayama are numerous and complex. Research indicates that engaging in yogic breathing can significantly enhance respiratory function. By improving lung capacity and promoting efficient gas exchange, Pranayama supports overall respiratory health. Techniques such as diaphragmatic breathing and slow, controlled inhalations and exhalations facilitate oxygenation at the cellular level, which is crucial for maintaining optimal bodily functions.
Moreover, studies have demonstrated the positive influence of Pranayama on neurocognitive functions. Improved focus, heightened alertness, and enhanced mental clarity have been reported among practitioners. These cognitive benefits may stem from the regulation of the autonomic nervous system, which in turn impacts stress response and emotional well-being. The psychophysiological effects of yogic breathing are profound, contributing to a balanced state of mind and promoting resilience to stressors.
Additionally, Pranayama has been linked to biochemical and metabolic improvements. Research findings suggest that the practice can stabilize blood glucose levels, enhance immune response, and regulate hormones. The interplay between breath control and metabolic functions is a promising area for future exploration, particularly in the context of managing lifestyle-related disorders such as obesity and diabetes.
Clinical Applications of Yogic Breathing
Beyond its physiological benefits, Pranayama has emerged as a valuable adjunctive therapy in various clinical conditions. Clinical studies have reported positive outcomes in individuals dealing with anxiety, depression, cardiovascular diseases, and respiratory ailments such as asthma. The calming effects of regulated breathing can alleviate symptoms of anxiety and stress, making it a useful tool in mental health interventions.
In the realm of cardiovascular health, the incorporation of yogic breathing techniques has shown promise in managing hypertension and improving heart rate variability. By fostering relaxation and reducing the body’s stress response, Pranayama contributes to maintaining cardiovascular stability. Additionally, individuals with chronic respiratory conditions have experienced improvements in lung function and quality of life through consistent practice of yogic breathing.
Safety and Precautions
While the literature indicates that yogic breathing can be safe and beneficial, it is crucial to practice under the guidance of a trained teacher to mitigate any potential risks. Inappropriate techniques or beliefs about traditional practices can lead to misapplications that may hinder progress or even cause physical stress. Therefore, proper training and a well-structured learning environment are essential for maximizing the benefits of Pranayama.
Research Gaps and Future Directions
Despite the encouraging evidence, there are notable gaps in the current research landscape. The existing studies often vary in methodology, sample sizes, and participant demographics, which complicates the generalization of results. Future research should focus on large-scale, rigorously designed studies that examine the mechanisms underpinning the benefits of yogic breathing. Investigating how various techniques may uniquely influence physiological and psychological states could lead to more tailored approaches for integrating Pranayama into health care practices.
Introduction
Yoga is an ancient practice rooted in Indian culture, acclaimed for its holistic approach to living. This traditional discipline encompasses a variety of practices, including ethical guidelines (Yama and Niyama), cleansing methods (Kriya), physical postures (Asana), breath control (Pranayama), focus techniques (Dharana), and meditation (Dhyana) [1], [2]. In recent times, there has been a surge of interest in investigating the benefits of these diverse Yoga techniques [3], [4]. Numerous scientific studies have examined the effects of specific Yoga practices—both individually and in combination—on healthy individuals as well as those experiencing various health issues [5]. Among these practices, Pranayama, or breath regulation, has received particular focus from researchers. This practice involves various techniques for controlling the rhythm of breathing, such as slowing down or regulating the breath, alternate nostril usage, sound chanting, and breath retention. Table 1 lists several Yoga breathing techniques described in classical texts of Hathayoga [2]. This review aims to provide a comprehensive overview of the scientific evidence supporting Yogic Breathing practices.
Table 1: Procedures for Various Yogic Breathing Practices
| Name of the Practice | Method of Practice |
|---|---|
| Kapalabhati | Sit upright with a straight back and neck. Inhale through both nostrils and exhale rapidly while contracting the abdomen at a pace of 60-120 breaths per minute. |
| Bastrika (Bellow’s Breath) | Inhale and exhale quickly and forcefully, ensuring not to strain, while moving the abdomen. This should be repeated for up to 100 breaths. |
| Nadishodhana/Nadishuddhi (Alternate Nostril Breathing) | Close the right nostril with the thumb, inhale through the left nostril. Close the left nostril and exhale through the right. Repeat by inhaling through the right and exhaling through the left for one round, continuing for the desired number of rounds. |
| Suryanuloma Viloma (Right Uninostril Breathing) | Close the left nostril and breathe in and out solely through the right nostril, maintaining a natural breathing rhythm. |
| Chandranuloma Viloma (Left Uninostril Breathing) | Similar to Suryanuloma Viloma, but breathing occurs exclusively through the left nostril while the right nostril is closed. |
| Suryabhedana (Right Nostril Initiated Breathing) | Close the left nostril and inhale through the right nostril. After inhalation, close the right nostril and exhale through the left to complete one round. Continue for the desired number of rounds. |
| Ujjayi (Psychic Breath) | Inhale and exhale through the nose at a normal pace while partially contracting the glottis to create a light snoring sound. Focus on the sensation of breath in the throat. |
| Bhramari (Bee Breath) | [Further details needed for this practice, depending on context and research]. |
This revised introduction and table present an overview of Yogic Breathing in a clear and concise manner, maintaining the integrity of the original content while improving readability and coherence.
2. Methodology
For this review, an extensive search was conducted using the online databases PubMed, PubMed Central, and IndMed, focusing on the keywords “Pranayama” and “Yogic Breathing.” This search resulted in a total of 1,400 references from the inception of these databases up to July 2017. We included experimental papers, case studies, and case series written in English that specifically highlighted the effects of yogic breathing. Studies that combined yogic breathing with other yoga practices were excluded from our review. Additionally, we excluded research written in languages other than English and those lacking accessible abstracts. After applying our inclusion and exclusion criteria and eliminating duplicates, we identified 68 studies that qualified for the final review.
The selected studies were categorized into two primary groups: physiological and clinical. Within these categories, they were further organized based on their key findings. The physiological assessments related to various yogic breathing practices included neurocognitive evaluations, psychophysiological changes, and measurements of respiratory, biochemical, and metabolic variables. Furthermore, we examined the impact of yogic breathing on a range of clinical conditions, such as hypertension, cardiac arrhythmias, bronchial asthma, pulmonary tuberculosis, cancer, diabetes mellitus, mental disabilities, stroke rehabilitation, smoking cessation, anxiety, and pain management.
3. Results
3.1. Neurocognitive Effects of Yogic Breathing
Ancient Indian texts on Yoga suggest a profound connection between breath and the mind, stating, “As the breath moves, so does the mind, and the mind ceases to move when the breath is halted.” This relationship has garnered significant interest from researchers examining the influence of yogic breathing on cognitive functions. An early review highlighted that various yogic breathing practices could affect brain activity in several ways.
3.1.1. Breathing Pace and Its Effects
Initial studies investigating the impact of yogic breathing on cognitive abilities focused on 15 minutes of high-frequency yogic breathing known as Kapalabhati. Research indicated that during the first five minutes, there was an increase in alpha wave activity, while theta wave activity was heightened primarily in the occipital region during the latter stages when compared to pre-exercise levels. Additionally, beta wave activity was observed to rise in the initial ten minutes within the occipital and, to a lesser extent, the parietal regions. Another investigation into cognitive performance revealed an increase in errors on a letter cancellation task after just one and five minutes of Kapalabhati practice.
The effects of another rapid-paced breathing technique, Bhastrika (referred to as the “bellows breath” in Hathayoga), were explored by Telles and colleagues, who reported diminished anticipatory responses after 18 minutes of practice. In a study involving 22 healthy school children, significant reductions were noted in both auditory reaction time (ART) and visual reaction time (VRT) after completing just nine rounds of Mukha Bhastrika. This approach showed promise for clinical applications as well, particularly for mentally challenged adolescents, who typically exhibit longer reaction times. A follow-up study revealed immediate reductions in both VRT and ART among 34 of these adolescents. Another investigation contrasting the effects of slow versus fast-paced Pranayama involved a 10-week regimen of 35 minutes daily. Notable improvements were recorded in executive functions, perceived stress levels, and reaction times across both groups, although only the fast-paced group showed enhancements in the reverse digit span task.
3.1.2. Effects of Bhramari Pranayama
Bhramari Pranayama, commonly referred to as the “female honeybee humming breath,” is another form of yogic breathing that appears to alter brain responses through the resonance created by its humming sound. Research has demonstrated that practicing Bhramari for just ten minutes can lead to the emergence of non-epileptic paroxysmal gamma waves on EEG readings. Moreover, studies have indicated that Bhramari enhances inhibitory control and reaction times in cognitive tasks requiring inhibition, particularly evident in a stop signal task involving 31 healthy male participants.
3.1.3. Effects of Nostril Manipulation on Breathing
Breathing techniques, particularly uninostril and alternate nostril breathing, hold significant importance in Yoga, as the nostrils are believed to symbolize the subtle energy channels known as Nadis [2], [15]. Specifically, the right nostril is associated with the Pingala Nadi, while the left nostril corresponds to the Ida Nadi. Research indicates that breathing through a single nostril can have varied effects on the human body. A study involving 51 participants found that performance on spatial tasks improved significantly during left nostril breathing for both men and women, whereas only a minimal and non-significant improvement was observed in verbal tasks [16].
Another investigation contrasted the effects of alternate nostril breathing with breath awareness. This study revealed a significant increase in P300 peak amplitudes at different locations on the scalp and a reduction in peak latency in the frontal scalp area after practicing alternate nostril breathing. In contrast, breath awareness only resulted in an increase in peak amplitude of P300 at the vertex region [17]. Inexperienced yogic practitioners exhibited increased Na-wave amplitude and decreased latency during Pranayama practice, although Pa-wave measurements showed no significant changes. The Pranayama utilized in this study consisted of purposefully controlled rhythmic breathing combined with breath retention [18].
A randomized controlled trial involving three groups of participants with essential hypertension assessed the impact of Nadishuddhi Pranayama and breath awareness, compared to a control session lasting 10 minutes. Results showed that Nadishuddhi significantly lowered both systolic and diastolic blood pressure, while both breathing techniques enhanced performance on the Purdue pegboard task, which evaluates manual dexterity and hand-eye coordination. The breath awareness group also experienced a reduction in systolic blood pressure when compared to participants engaging in control activities such as reading a magazine [19].
Clinically, uninostril breathing has been applied in stroke rehabilitation, where a 10-week practice led to decreased anxiety in 11 individuals post-stroke and improved language skills in patients with aphasia [20]. A separate case series demonstrated that implementing forced uninostril breathing alongside speech therapy resulted in improvements in correct information units and word productivity for individuals with post-stroke aphasia [21].
In summary, various yogic breathing techniques have been shown to positively affect neuro-cognitive abilities, and some have even been applied successfully in clinical settings, yielding beneficial outcomes. A summary of the neurocognitive effects of yogic breathing techniques can be found in Table 2
Table 2: Neurocognitive Effects of Yogic Breathing
| Sl No. | Author | Year | Sample Size | Variables Studied | Findings |
|---|---|---|---|---|---|
| 1 | Stancák et al. | 1991 | 11 | EEG | Alpha activity increased during the first 5 minutes of Kapalabhati (KPB). Theta activity rose during the subsequent 15 minutes, particularly in the occipital region, compared to pre-exercise levels. Beta 1 activity also increased in the occipital and, to a lesser extent, parietal regions during the first 10 minutes. |
| 2 | Telles et al. | 1993 | 11 | Middle Latency Auditory Evoked Potential | The amplitude of the Na-wave increased while its latency decreased during pranayama practice, although the Pa-wave remained largely unchanged. |
| 3 | Jella & Shannahoff-Khalsa | 1993 | 51 | Spatial and Verbal Task Performance | There was a notable enhancement in spatial task performance during left nostril breathing; verbal task performance showed a non-significant increase during right nostril breathing. |
| 4 | Bhavanani et al. | 2003 | 22 | Visual Reaction Time (VRT) and Auditory Reaction Time (ART) | VRT and ART significantly decreased in school children after completing 9 rounds of Mukha Bhastrika. |
| 5 | Vialatte et al. | 2008 | 8 | EEG | Non-epileptic paroxysmal gamma waves were observed during the practice of Bhramari Pranayama. |
| 6 | Bhavanani et al. | 2012 | 34 | VRT and ART | Following 9 rounds of Mukha Bhastrika, both VRT and ART showed significant reductions among mentally challenged children. |
| 7 | Telles et al. | 2013 | 90 | Blood Pressure (BP) and Purdue Pegboard Task | A decrease in systolic (SBP) and diastolic blood pressure (DBP) was observed after Nadishuddhi, alongside improved performance on the Purdue pegboard task with both hands and the right hand. The breath awareness group also experienced a reduction in SBP. |
| 8 | Telles et al. | 2013 | 20 | P300 | Significant increases in P300 peak amplitudes at various scalp sites and a notable decrease in peak latency at the frontal scalp region were recorded following alternate nostril Yoga breathing. Breath awareness practices also resulted in a significant rise in P300 peak amplitude at the vertex region. |
| 9 | Pradhan | 2013 | 36 | Digit Letter Substitution Task (DLST), Six Letter Cancellation Test (SLCT) | KPB practices for both 1 and 5 minutes showed no significant effect on SLCT and DLST scores, although there was an increase in errors post-practice. |
| 10 | Telles et al. | 2013 | 70 | Reaction Time | An 18-minute session of Bhastrika Pranayama led to a statistically significant decrease in the number of anticipatory responses compared to baseline measures. |
| 11 | Rajesh et al. | 2014 | 31 | Stop Signal Task | A noticeable reduction in stop signal reaction time was recorded after practicing Bhramari Pranayama for 10 minutes, along with increased go reaction times in the Bhramari group when compared to a deep breathing group practiced for the same duration. |
3.2. Psychophysiological Effects of Yogic Breathing
Human respiration uniquely operates under both autonomic and voluntary nervous control, making it a focal point in yogic literature. Extensive research has investigated how regulation of breath through yogic practices influences autonomic functions (AFT). These studies have utilized a variety of assessment measures, including blood pressure (both systolic and diastolic), heart rate, heart rate variability, respiratory rate, galvanic skin resistance, and pulse rate. The impacts of yogic breathing on AFT have been examined over both short and long time frames.
3.2.1. Effects of Nostril Manipulation
Research involving eight healthy volunteers revealed that engaging in right forced uninostril breathing (UNB) led to an increase in heart rate, indicating sympathetic nervous system activation. A three-arm randomized controlled trial (RCT) that measured heart rate variability as a metric of autonomic activity found sympathetic arousal in the group performing right UNB, while the left UNB group experienced increased parasympathetic activity after a six-week period of nostril breathing. Another pilot RCT involving twelve individuals demonstrated that 20 minutes of alternate nostril breathing resulted in increased galvanic skin resistance, a marker of parasympathetic activity. Although no significant changes were observed in blood pressure or pulmonary function tests, this study confirmed the capacity of yogic breathing to induce a parasympathetic shift in autonomic functions within just one week.
Further research exploring the effects of alternate nostril breathing (ANB) employed a 30:15 ratio for expirations to inspirations, showing that the practice encourages a parasympathetic shift. Specifically, Nadishuddhi Pranayama, conducted at a rate of one breath per minute, was found to enhance sinus arrhythmia and reduce the low-frequency component of heart rate variability. Additionally, this practice led to a decrease in average breath rate, reinforcing the parasympathetic shift in the autonomic nervous system (ANS). Another investigation indicated that practicing Nadishuddhi Pranayama for 15 minutes daily over four weeks resulted in improved peak expiratory flow rate, increased pulse pressure, and reductions in pulse rate, respiratory rate, and diastolic blood pressure among healthy participants.
Training in Nadishuddhi Pranayama, combined with breath holding for four weeks, resulted in lower baseline heart rate, systolic blood pressure, and diastolic blood pressure—attributed to enhanced vagal tone and diminished sympathetic discharge. A study assessing six variations of nostril breathing on cardiovascular metrics and reaction time in twenty experienced practitioners found that nine rounds of Nadishuddhi, left nostril breathing, and left-initiated breathing led to reductions in blood pressure and heart rate. Conversely, right nostril breathing and right-initiated breathing were associated with increases in these parameters. Notably, no changes were observed with normal breathing, while reaction time improved following right nostril and right-initiated breathing practices. These effects were linked to the nostril utilized for inspiration rather than expiration.
3.2.2. Effects of Breathing Pace on Psychophysiological Responses
The pace of breathing has a significant impact on psychophysiological responses. A pilot study investigating the effects of extremely slow breathing—specifically at a rate of 1 breath per minute for 20 minutes—revealed notable changes in various cardiovascular risk factors. Hemodynamic variables such as stroke index, heart rate (HR), cardiac index, end-diastolic index, peak flow, ejection fraction, thoracic fluid index, contractility index, ejection ratio, systolic time ratio, acceleration index, as well as systolic, diastolic, and mean arterial pressures, left stroke work index, and systemic vascular resistance index all exhibited dramatic modifications. These findings suggest that slow-paced breathing, particularly when combined with internal breath holds, may influence the brainstem’s cardiorespiratory center, affecting Mayer wave patterns.
In another study involving 17 subjects with no prior experience in breath control, results indicated an increase in baroreflex sensitivity (BRS) following slow breathing practices, regardless of whether Ujjayi Pranayama was included. The most significant decreases in blood pressure (BP) and increases in BRS were observed when participants engaged in slow breathing with equal durations for inhalation and exhalation at a rate of 6 breaths per minute. Furthermore, a comparative study on fast and slow Pranayama training over three months highlighted a rise in parasympathetic activity and a decrease in sympathetic activity among participants practicing slow breathing, while those in the fast breathing group showed no considerable changes in autonomic functions.
A randomized controlled trial (RCT) involving 90 young healthcare students assessed the impact of both slow and fast Pranayama training over three months. Both groups reported reduced perceived stress; however, improvements in cardiovascular variables such as HR, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were only evident in the slow Pranayama participants. In contrast, the fast Pranayama group did not demonstrate notable alterations in cardiovascular measures. While hand grip strength (HGS) and endurance (HGE) improved with fast Pranayama training, HGS alone increased in the slow Pranayama group after 12 weeks. Additionally, a vigorous practice of Kapalabhati increased low-frequency (LF) power and the LF:HF ratio while decreasing high-frequency (HF) power in heart rate variability (HRV), signaling heightened sympathetic arousal; similar findings regarding increased HR, SBP, and DBP were noted in a separate study involving 17 individuals during Kapalabhati practice, where BRS decreased.
Training in Mukha Bhastrika, characterized by rapid breathing over 12 weeks, resulted in lower basal HR, an increased Valsalva ratio, and substantial differences in HR during deep breathing exercises, as well as a less pronounced drop in BP during posture variations. These results indicated a significant enhancement in parasympathetic activity following extended Mukha Bhastrika training. To further explore the mechanisms underlying cardiovascular parameter modulation from slow-paced Bhastrika Pranayama, research compared HR and BP effects from a 5-minute Bhastrika session, with and without the administration of hyoscine-N-butylbromide (Buscopan), a parasympathetic blocker. The group practicing Bhastrika without the drug showed decreases in SBP, DBP, and HR, whereas those who received the drug exhibited no significant changes. This led to the conclusion that the observed modulation of the autonomic nervous system (ANS) during slow-paced Bhastrika practice is likely due to increased parasympathetic activity.
3.2.3. Effects of Other Yogic Breathing Techniques
Recent research utilizing heart rate variability (HRV) measurements has identified parasympathetic withdrawal during Bhramari Pranayama practice, which returned to baseline levels after the practice concluded. Medical students reported reduced stress levels after engaging in a combination of Pranayama techniques for an hour each day, five days a week for two months. The HRV data revealed decreased very low frequency (VLF) and LF components, along with an increased HF component, indicating a shift towards greater parasympathetic activity.
The relaxation achieved through Pranayama was further leveraged to alleviate test anxiety and improve academic performance among 107 postgraduate students. An RCT found that only 33% of students who practiced Pranayama experienced high test anxiety after a semester, a sharp contrast to the 66.67% observed in the control group. Moreover, those in the Pranayama group also scored higher on tests compared to their peers in the control group.
Our observations reveal that many yogic breathing techniques significantly impact autonomic functions. Generally, most yogic breathing practices promote a shift toward increased parasympathetic activity within the autonomic nervous system (ANS), with the exception of high-frequency yoga breathing techniques such as Kapalabhati [41]. The psychophysiological effects of yogic breathing are summarized in Table 3.
Table 3. Summary of Psychophysiological Changes Resulting from Yogic Breathing
| Sl No. | Author | Year | Sample Size | Variables Studied | Findings |
|---|---|---|---|---|---|
| 1 | Stancák et al. | 1991 | 17 | BP, ECG, and respiration | Increase in heart rate (HR), systolic BP (SBP), and diastolic BP (DBP) during Kapalabhati. Baroreflex sensitivity (BRS) decreased during Kapalabhati. |
| 2 | Raghuraj et al. | 1998 | 12 | HRV | Increased low-frequency (LF) power and LF/HF ratio observed, while high-frequency (HF) power significantly decreased after Kapalabhati. No significant changes noted after Nadishuddhi. |
| 3 | Pal et al. | 2004 | 60 | Autonomic Function Tests | Significant increase in parasympathetic activity and decrease in sympathetic activity were observed in the slow breathing group after three months, whereas the fast breathing group showed no significant changes in autonomic functions. |
| 4 | Shannahoff-Khalsa et al. | 2004 | 4 | Cardiovascular Variables | Breathing at a rate of one breath per minute with a 20:20:20 second ratio caused dramatic variations in hemodynamic variables. |
| 5 | Veerabhadrappa et al. | 2011 | 50 | Cardiovascular Autonomic Reactivity | Mukh Bhastrika training resulted in increased parasympathetic activity (reduced basal HR, increased Valsalva ratio, and deep breathing HR difference) and decreased sympathetic activity (reduction of SBP fall on postural variation). |
| 6 | Bhimani et al. | 2011 | 59 | HRV, Stress Questionnaire | A combination of Pranayama practices resulted in reduced stress levels. HRV showed a decrease in very low-frequency (VLF) and LF components, while the HF component increased. |
| 7 | Ghiya & Lee | 2012 | 23 | HRV | lnTP, lnLF, and lnHF were higher following both Alternate Nostril Breathing and Paced Breathing compared to baseline. Mean Arterial Pressure (MAP) and lnLF/lnHF did not show significant differences across conditions. |
| 8 | Mason et al. | 2013 | 17 | BRS | BRS improved with slow breathing techniques, with or without expiratory Ujjayi, except for inspiratory plus expiratory Ujjayi. The highest increase in BRS and decrease in blood pressure were observed during slow breathing with equal inhalation and exhalation. |
| 9 | Sinha et al. | 2013 | 25 | Expiration: Inspiration Ratio (30:15) | A 5-minute daily practice of alternate nostril breathing for six weeks resulted in increased parasympathetic tone. |
| 10 | Adhana et al. | 2013 | 30 | Electromyogram (EMG), GSR, FTT, HR, RR, BP | Slow yogic breathing led to decreased SBP and DBP, along with significant changes in HR, RR, EMG, GSR, and an increase in fingertip temperature (FTT). |
| 11 | Turankar et al. | 2013 | 12 | BP, Pulmonary Function Tests, GSR | The practice of Anulom Vilom Pranayama with breath-holding increased GSR; however, no significant changes in BP or pulmonary function were noted. |
| 12 | Sharma et al. | 2013 | 90 | Perceived Stress Scale (PSS), HR, BP | PSS scores decreased in both fast and slow Pranayama groups, while HR, DBP, and Rate Pressure Product (RPP) decreased only in the slow Pranayama group. |
| 13 | Pal et al. | 2014 | 85 | HRV | HRV indices indicating sympathetic activity rose in the Right Nostril Breathing group, while indices for parasympathetic activity increased in the Left Nostril Breathing group. |
| 14 | Bhavanani et al. | 2014 | 20 | Reaction Time, HR, BP | BP decreased after practices such as Chandara Nadi Pranayama, Chandrabhedana, and Nadishuddhi, while surya nadi pranayama and suryabhedana increased BP. Reaction time reduced with Surya Nadi and Surya Bhedana. |
| 15 | Goyal et al. | 2014 | 50 | BP, HR, Rate Pressure Product | Pranayama combined with antihypertensive medications significantly lowered BP compared to medications alone, and RPP significantly decreased in the Pranayama group. |
| 16 | Hakked et al. | 2017 | 27 | Spirometry | One month of yogic breathing training improved lung function in professional swimmers. |
| 17 | Nivethitha et al. | 2017 | 16 | HRV | While practicing Bhramari Pranayama, the HF component of HRV decreased, and the LF component and HR increased, with changes returning to baseline after the practice ended. |
Through these studies, it is evident that various yogic breathing techniques can lead to measurable and beneficial changes in physiological and psychological parameters, influencing overall health and well-being.
3.3. Impact of Yogic Breathing on the Respiratory System
Training in yogic breathing has proven to be an effective method for improving pulmonary function. Research indicates that adopting a slow breathing rate of 6 breaths per minute leads to significant increases in vital capacity (VC) after 2 and 5 minutes, along with enhancements in forced vital capacity and forced inspiratory vital capacity, and peak inspiratory flow rate measurements after 2, 5, and 10 minutes [42]. Another comparative study on the effects of a 12-week regimen of slow and fast Pranayama training on pulmonary function tests revealed that the participants in the slow Pranayama group experienced significant improvements in peak expiratory flow rate (PEFR) and forced expiratory volume in 25% of the pulmonary capacity (FEV25). Conversely, the fast Pranayama group noted significant improvements in the FEV1/FVC ratio, PEFR, and forced expiratory flow (FEF25-75) [43]. A more recent study highlighted the positive effects of a month-long yogic breathing program on the pulmonary functions of competitive swimmers [44]. Collectively, these findings suggest that yogic breathing positively influences respiratory physiology, although more comprehensive research is needed.
3.4. Effects of Yogic Breathing on Biochemical and Metabolic Variables
The underlying reasons for the physiological changes observed with yogic breathing practices have intrigued researchers. One study monitored arterial blood gas levels during Pranayama and found no significant changes in arterial blood oxygen levels, indicating that the observed benefits may stem from neural mechanisms associated with the practice [45]. Another investigation found that practicing Kapalabhati for just one minute resulted in decreased blood urea levels and increased creatinine and tyrosine levels. These changes were attributed to decarboxylation and oxidation processes that might lead to reduced activity in respiratory centers [46].
3.4.1. Changes in Oxygen Consumption During Yogic Breathing
Oxygen consumption is an important marker for assessing metabolic activity in the body. Research on Ujjayi Pranayama, along with both short and prolonged periods of Kumbhaka (breath-holding), revealed that oxygen consumption increased during short Kumbhaka sessions but diminished with extended breath-holding [47]. Additionally, breathing through the right nostril was linked to higher oxygen consumption and improved metabolic status compared to breathing through the left nostril or alternating nostrils for the same duration [48][49]. These findings suggest that right nostril breathing may be beneficial for conditions associated with lower metabolic rates, such as obesity. However, it is essential to exercise caution, as right nostril breathing has also been found to elevate blood pressure [50].
3.4.2. Yogic Breathing and Oxidative Stress
Yogic breathing has been identified as an effective strategy to reduce oxidative stress. Studies have shown that this practice decreases the free radical load and increases levels of superoxide dismutase (SOD) among healthy participants when compared to a control group [51]. Athletes, who frequently experience fatigue from oxidative stress due to strenuous exercise, have a heightened need for antioxidant support [52]. Practicing yogic breathing for one hour has been found to significantly bolster antioxidant defense capabilities in athletes following rigorous exercise, especially when compared to a control group that engaged in quiet sitting. This improvement was correlated with lower cortisol levels and elevated melatonin levels. Consequently, researchers suggest that rhythmic yogic breathing may offer protective benefits against the long-term effects of free radicals, particularly for athletes [53]
3.4.3. Molecular Changes Induced by Yogic Breathing
Several studies have established the impact of yogic breathing on stress levels, physiological variables, and cognitive function. This prompted a recent investigation into the molecular biomarkers associated with these processes, focusing on salivary proteomes during 20 minutes of yogic breathing practice. The findings revealed differential expression of specific biomarkers, notably Deleted in Malignant Brain Tumor-1 (DMBT1) and Ig lambda-2 chain C region (IGLC2), in the participants practicing yogic breathing. Notably, DMBT1 levels were found to be elevated by 10-fold at the 10-minute mark and by 11-fold at the 15-minute mark in the yogic breathing group, while it remained undetectable in the control group. Additionally, IGLC2 demonstrated a significant increase when compared to the controls. This study marks a pioneering effort in demonstrating the feasibility of using acute yogic breathing practices for stimulating and detecting salivary protein biomarkers.
The body of evidence indicates that yogic breathing not only modulates metabolism but also induces changes in biochemical markers. These alterations may correlate with the age-old concept of Prana (vital energy) which is believed to govern the body’s physical functions. Furthermore, the studies align with traditional narratives that highlight the stimulating effects of right nostril breathing, as noted in ancient Indian texts. Table 4 provides a summary of the biochemical and metabolic changes observed following yogic breathing practices.
Table 4. Biochemical and Metabolic Changes Following Yogic Breathing
| Sl No. | Author | Year | Sample Size | Variables Studied | Findings |
|---|---|---|---|---|---|
| 1 | Pratap et al. | 1978 | 10 | Arterial blood gas | No significant changes in arterial blood gases were observed post-Pranayama; neural mechanisms may account for mental effects. |
| 2 | Desai & Gharote | 1990 | 12 | Blood urea, creatinine, tyrosine | Blood urea decreased, while creatinine and tyrosine levels increased after 1 minute of Kapalabhati. |
| 3 | Telles & Desiraju | 1991 | 10 | Oxygen consumption | An increase in oxygen consumption was noted with short kumbhaka, while prolonged kumbhaka led to a reduction. |
| 4 | Telles et al. | 1994 | 48 | Oxygen consumption, GSR | A baseline increase in oxygen consumption was observed following right nostril breathing, exceeding that of alternate nostril breathing; GSR increased with left nostril breathing. |
| 5 | Telles et al. | 1996 | 12 | Oxygen consumption, blood pressure, digit pulse volume, GSR | Right nostril breathing resulted in increased oxygen consumption and systolic blood pressure, along with a decrease in digit pulse volume; both right nostril and normal breathing reduced GSR. |
| 6 | Bhattacharya et al. | 2002 | 60 | SOD, Free radicals | Free radicals significantly decreased post-Pranayama practice, while SOD levels increased insignificantly compared to the control group. |
| 7 | Balasubramanian et al. | 2015 | 20 | Salivary Proteome – DMBT1 and IGLC2 | DMBT1 levels were increased by 10-fold in the yogic breathing group, remaining undetectable in the time-matched controls; IGLC2 also showed a significant increase. |
This overview underscores the growing evidence of the molecular effects of yogic breathing, enhancing our understanding of its physiological and biochemical implications.
3.5 Health Benefits of Yogic Breath Regulation
3.5.1 Yogic Breathing and Cardiovascular Diseases
The physiological effects of yogic breathing techniques have been extensively studied, aligning with traditional understandings found in ancient texts. Several experiments conducted in clinical settings aimed to investigate the immediate impact of these techniques on individuals with hypertension. For instance, a study found that practicing Sukha Pranayama for just five minutes at a rate of six breaths per minute significantly reduced heart rate (HR), systolic blood pressure (SBP), pulse pressure, mean arterial pressure, rate-pressure product, and double product, with minimal effect on diastolic pressure. A similar reduction in SBP, HR, and pulse pressure was observed after five minutes of Pranava Pranayama. Another study reported a notable decrease in HR, SBP, and pulse pressure among hypertensive patients following 27 rounds of left unilateral nostril breathing (UNB). Long-term benefits were also evident in a separate study, which revealed that a three-month regimen of slow breathing for five minutes daily—following a 2:1 ratio of exhalation to inhalation—led to significant reductions in both systolic and diastolic blood pressure, as well as HR and respiratory rate, alongside an increase in fingertip temperature. Moreover, a six-week training program in Pranayama combined with antihypertensive medications resulted in a more significant reduction in blood pressure compared to medication alone, with notable improvements in the rate-pressure product among those practicing Pranayama. Additionally, research has shown that practicing Pranayama positively affects patients with cardiac arrhythmias, evidenced by improved indices of ventricular repolarization dispersion on ECG readings after sessions of Pranayama.
3.5.2 Yogic Breathing and Respiratory Disorders
The benefits of yogic breathing have also been studied in relation to respiratory disorders. One particular study focused on asthmatic individuals, utilizing a Pink City Lung exerciser to guide breathing at a 1:2 inhalation-to-exhalation ratio for 15 minutes daily over a two-week period. Findings revealed significant improvements in forced expiratory volume in 1 second (FEV1), peak expiratory flow rate, symptom scores, and reliance on inhalers when compared to a control group using a placebo device. Additionally, the threshold of histamine required to induce a 20% reduction in FEV1 (PD 20) increased notably during Pranayama breathing but showed no change with the placebo, indicating decreased airway reactivity. Further research has confirmed both the stability and improvement of symptoms in asthma patients practicing yogic breathing. Recent studies have also cited enhancements in FEV1 and peak expiratory flow rate (PEFR) for those with asthma, while another showed beneficial effects of Kapalabhati, which increased FEV1, forced vital capacity (FVC), and the FEV1:FVC ratio after just ten minutes of practice.
In addition to asthma, Pranayama has been shown to assist individuals in overcoming cigarette addiction. A study indicated that ten minutes of yogic breathing significantly alleviated cravings compared to controls watching a breathing instructional video, though no noticeable effects were recorded on mood or physical symptoms. Furthermore, a case study documented substantial improvements in a patient with pulmonary tuberculosis (PTB) who practiced Bhramari Pranayama for 45 minutes, three days a week over eight weeks. This individual experienced increases in body weight, body mass index, symptom scores, pulmonary function, and overall health-related quality of life, with a conversion from a positive to a negative result for acid-fast bacilli.
3.5.3 Yogic Breathing and Diabetes Mellitus
Diabetes presents a significant healthcare challenge in contemporary society, impacting quality of life (QoL) and necessitating lifestyle changes. Research has evidenced notable improvements in QoL among diabetic patients engaged in a comprehensive yogic breathing program, showing a trend toward enhanced glycemic control compared with those receiving standard treatment alone. Recognizing that diabetic patients often experience a sympathovagal imbalance, a six-month regimen of Pranayama alongside standard therapy exhibited improvements in sympathetic function, surpassing the outcomes observed in patients adhering solely to conventional treatment.
3.5.4. The Role of Yogic Breathing in Various Health Conditions
A controlled study assessing the impact of slow Pranayama breathing versus regular breathing on pain perception found that participants reported lower levels of pain intensity and unpleasantness, particularly when faced with moderately painful thermal stimuli while practicing slow breathing [70]. Furthermore, a pilot randomized controlled trial (RCT) indicated that when Pranayama was used as an adjunct technique alongside standard care for chemotherapy patients, it led to improvements in sleep quality, overall quality of life (QoL), and reductions in anxiety levels between chemotherapy sessions [71]. Another RCT involving 160 cancer patients undergoing radiotherapy showed notable differences in biomarkers such as protein thiols and serum glutathione among those who practiced a combination of Nadishuddi, Bhramari, and Shitali Pranayama for 30 minutes, twice daily, five days a week, compared to those who only received radiotherapy [72]. Additionally, Pranayama was found to be effective in alleviating cancer-related fatigue when used as a complementary therapy to radiotherapy [73].
Table 5 provides a summary of the positive health effects associated with yogic breathing across various clinical populations.
Table 5. Effects of Yogic Breathing on Diverse Clinical Populations
| Sl No. | Author | Year | Sample Size | Disorder | Variables Studied | Findings |
|---|---|---|---|---|---|---|
| 1 | Singh et al. | 1990 | 18 | Bronchial Asthma | Airway reactivity, airway caliber | Increased histamine requirement for reduced Forced Expiratory Volume in 1 second (FEV1) observed in the Pranayama group with a 1:2 inhalation-to-exhalation ratio compared to controls. |
| 2 | Cooper et al. | 2003 | 90 | Bronchial Asthma | Symptom scores, FEV1 | Stability of symptoms in the Pranayama group at 3 and 6 months while Buteyko breathing group experienced symptom reduction, with no significant difference in FEV1 between groups. |
| 3 | Saxena & Saxena | 2009 | 50 | Bronchial Asthma | Peak Expiratory Flow Rate (PEFR), FEV1 | A combination of slow breathing, Bhramari, and Omkara significantly enhanced symptoms, FEV1, and PEFR in bronchial asthma patients. |
| 4 | Prem et al. | 2013 | 120 | Bronchial Asthma | Quality of life, Pulmonary Function Tests (PFT) | Buteyko breathing showed better improvements in quality of life and asthma control compared to the Pranayama group. |
| 5 | Raghavendra et al. | 2016 | 60 | Bronchial Asthma | FEV1, FVC, FEV1:FVC | A 10-minute practice of Kapalabhati improved FEV1, FVC, and the FEV1:FVC ratio in mild to moderate asthma patients compared to controls who performed deep breathing exercises. |
| 6 | Dabhade et al. | 2012 | 15 | Cardiac Arrhythmias | ECG | In patients with cardiac arrhythmias, Pranayama sessions improved QTd, QTc-d, JTd, and JTc-d, indicating reduced ventricular repolarization dispersion. |
| 7 | Dhruva et al. | 2012 | 16 | Cancer | Cancer-related symptoms, quality of life | Improved sleep quality, QoL, and reduced anxiety observed after Pranayama practice between chemotherapy sessions. |
| 8 | Chakrabarty et al. | 2015 | 160 | Cancer | Cancer-related fatigue | A reduction in cancer-related fatigue scores was reported among those practicing Pranayama alongside radiation therapy compared to those receiving only radiation therapy. |
| 9 | Jyotsna et al. | 2012 | 49 | Type 2 Diabetes Mellitus | WHOQoL BREF, fasting blood sugar (FBS), postprandial blood sugar (PPBS), HbA1C | Significant improvements in QoL were noted in the yogic breathing group compared to standard treatment; trends toward improved glycemic control were also observed. |
| 10 | Jyotsna et al. | 2013 | 64 | Type 2 Diabetes Mellitus | Cardiac autonomic functions | Pranayama, along with standard therapy, enhanced sympathetic functions in diabetic patients compared to those on standard therapy alone. |
| 11 | Bhavanani et al. | 2012 | 22 | Hypertension | Heart rate, blood pressure | Immediate reductions in heart rate, systolic pressure, and pulse pressure were observed following Chandra Nadi Pranayama. |
| 12 | Bhavanani et al. | 2012 | 29 | Hypertension | Heart rate, blood pressure | Notable reductions in systolic pressure, pulse pressure, and heart rate were recorded in hypertensive patients practicing Pranava Pranayama. |
| 13 | Marshall et al. | 2013 | 11 | Stroke | Attention, language, spatial abilities, depression, anxiety | Uninostril breathing practice led to reduced anxiety in post-stroke patients and improved language skills in those with aphasia. |
| 14 | Marshall et al. | 2015 | 3 | Stroke | WAB-R and CADL-2 | In 2 out of 3 stroke-induced aphasia cases, forced uninostril breathing combined with speech therapy enhanced correct information units and word productivity. |
| 15 | Nemati. | 2013 | 107 | Test Anxiety | Sarason’s test anxiety scale, test performance | After practicing Pranayama for a semester, students reported less severe test anxiety and achieved higher test performance scores compared to a control group. |
| 16 | Mooventhan et al. | 2014 | 1 | Pulmonary Tuberculosis | Weight, BMI, symptom scores, pulmonary function | Significant improvements in weight, BMI, symptom scores, pulmonary function, and health-related quality of life were noted, along with conversion from positive to negative FME for acid-fast bacilli. |
This body of research suggests that the practice of yogic breathing, particularly Pranayama, can have a range of beneficial effects across different health conditions, making it a valuable adjunct therapy in various clinical settings.
3.6. Complications of Yogic Breathing
Pranayama, or yogic breathing, is widely regarded as a safe practice; however, our literature review revealed a single case report highlighting potential adverse effects. Specifically, a case of spontaneous pneumothorax was documented, attributed to a breathing technique known as Kapalabhati. Furthermore, the review noted instances of rectus sheath hematoma and pneumomediastinum occurring as a result of practicing unspecified Pranayama techniques.
Conclusion
In summary, Pranayama represents an ancient practice rich in history and wisdom that has gained validation in modern scientific literature. Its multifaceted benefits span across physiological, cognitive, and clinical domains, presenting a holistic approach to health and wellness. As the research community delves deeper into the intricacies of yogic breathing, it is poised to uncover further insights that will enhance our understanding of the interplay between breath, body, and mind. Emphasizing the safety and proper guidance in practice, the exploration of Pranayama could not only enrich individual health experiences but also pave the way for integrative approaches in clinical and therapeutic settings. Embracing this ancient wisdom in our contemporary society offers immense potential for fostering well-being and resilience in an increasingly complex world.
Pranayama, or yogic breathing techniques, have been shown to positively impact neurocognitive function, autonomic and pulmonary performance, as well as biochemical and metabolic processes within the body. Clinical studies indicate that these breathing practices can regulate cardiovascular parameters in individuals with hypertension and cardiac rhythm disorders. They also alleviate symptoms and improve lung function in patients with bronchial asthma, assist in weight management and symptom relief for those with pulmonary tuberculosis, and enhance mood in individuals quitting smoking. Additionally, yogic breathing has been shown to decrease reaction times in children with disabilities, manage anxiety and stress in students, modulate pain perception, and enhance quality of life and sympathetic activity in diabetes patients. Furthermore, it may help alleviate cancer symptoms and bolster antioxidant levels in patients undergoing radiotherapy and chemotherapy. Therefore, these safe and cost-effective yogic breathing practices could play a significant role in both the prevention and management of various non-communicable diseases, and may also assist in treating communicable diseases like pulmonary tuberculosis.
However, this review has its limitations, primarily due to the reliance on freely accessible online databases, which may restrict access to comprehensive research in this area. This review also focuses solely on the existing scientific literature regarding yogic breathing without attempting to assess the statistical validity of the data discussed.
In summary, our findings suggest that yogic breathing is a safe practice when conducted under the guidance of a trained instructor. While numerous studies illustrate its benefits, many lack methodological rigor. Given the promising effects of yogic breathing, further large-scale studies with improved methodological designs are necessary to explore the underlying mechanisms associated with these practices.