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Knowledge · Therapies

Yoga

Yoga is one of the most extensively studied complementary therapies. The evidence base demonstrates a broad spectrum of applications but remains heterogeneous and methodologically limited in many areas. Notably, research has focused heavily on fatigue and cognitive parameters, while other indications have been examined only sporadically.

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1. What Yoga as a Practice Entails

Yoga comprises a system of physical, mental, and spiritual practices originating in ancient Indian philosophy. Modern research applications typically focus on Hatha Yoga, which combines physical postures (asanas), breathing techniques (pranayama), and meditation. Its implementation varies by style (e.g., Iyengar, Vinyasa) and objective, though studies often employ standardised protocols with defined sequences and durations. The tradition emphasises the interplay between body posture, breath, and mental focus, frequently investigated in Western research as a multimodal approach.

For interpreting the evidence base, it is crucial to recognise that yoga is not a uniform practice but encompasses a variety of techniques with differing emphases. Breathing exercises such as Sheetali Pranayama or Bhramari Pranayama are often examined in isolation, while other studies employ complex programmes combining asanas, meditation, and relaxation techniques. This diversity of forms undermines comparability, as effects cannot be attributed to a single component. Additionally, details on intensity, duration, and the qualifications of instructors are frequently lacking, limiting reproducibility.

2. How Robust the Research Is

Human studies span a broad range of applications, with fatigue, cognitive function, and safety aspects predominating. Further focal areas include oncology, cardiovascular health, and metabolic regulation. The most cited works concentrate on chronic back pain, hypertension, and psychological distress such as stress or anxiety, particularly in the context of the COVID-19 pandemic. Review articles also address cardiovascular effects and immune modulation, though with low evidence strength.

Methodologically, the field is characterised by heterogeneous study designs. Controlled trials frequently use active controls, such as exercise therapy or standard treatment, complicating the isolation of specific yoga effects. Observational studies provide indications of associations but do not permit causal inferences. Basic research primarily investigates autonomic regulatory mechanisms or neuroendocrine markers, though often confined to laboratory conditions. Study quality varies widely: while some randomised controlled trials (RCTs) achieve high citation rates, many lack details on blinding, compliance, or long-term effects. Generalisability to practice is limited, as studies often focus on specific populations (e.g., healthcare workers, cancer patients).

Distribution of controlled human studies by application area — numbers are not additive, as a single study may be assigned to multiple areas:

Application areacontrolled studies
Fatigue and stress17
Cognition and mental health13
Safety and tolerability9
Oncology8
Cardiovascular system5
Metabolism3
Musculoskeletal system3
Immune system3

3. Common Claims — and What the Data Actually Show

StatementEvidence base
Limited evidence: Controlled studies demonstrate short-term effects on cardiovascular markers; no robust long-term data exist on sustained blood pressure reduction. Most studies examine specific breathing techniques rather than complex yoga programmes.
Sparse data: Some studies suggest effects on attention or memory, but results are inconsistent. The populations studied primarily include patients with hypertension or stress, not healthy individuals.
No robust data: Observational studies show associations with immune markers, but controlled studies on yoga’s immunological effects are lacking.
Limited applicability: Safety studies focus on oncological or cardiovascular patients. Data are still emerging for high-risk groups such as pregnant women or individuals with severe neurological conditions.

4. The Most Robust Studies

Ranked by evidential strength, not by popularity. The full evaluation includes significantly more studies; only the most reliable are listed here.

Controlled Human Studies

  • 1 A comprehensive yoga programme improves pain, anxiety and depression in chronic low-back-pain patients more than exercise: an RCT (2012)
  • 2 Effect of Sheetali pranayama on cardiac autonomic function among patients with primary hypertension: a randomised controlled trial (2020)
  • 3 Effect of Bhramari Pranayama intervention on stress, anxiety, depression and sleep quality among COVID-19 patients in home isolation: a randomised controlled trial (2022)
  • **** Efficacy of pranayama in preventing COVID-19 in exposed healthcare professionals: a quasi-randomised clinical trial (2023)
  • **** Yogic Pranayama and Diaphragmatic Breathing: Adjunct Therapy for Intraocular Pressure in Patients With Primary Open-Angle Glaucoma: A Randomised Controlled Trial (2021)
  • **** Proposed physiological mechanisms of pranayama: a discussion (2024)
  • 4 A Randomised Controlled Trial on Pranayama and Yoga Nidra for Anxiety and Depression in Patients With Cervical Cancer Undergoing Standard of Care (2024)
  • 5 The Effects of Pranayama or Deep Breathing Exercises on Fatigue and Sleep Quality in Women Receiving Radiation Therapy for Breast Cancer (2023)
  • 6 Effect of six months of pranayama training on stress-induced salivary cortisol response among adolescents: a randomised controlled study (2022)
  • 7 The Effect of Pranayama Applied to Haemodialysis Patients on Fatigue: A Randomised Controlled Trial (2023)
  • 8 Effect of yoga-based lifestyle and dietary modification in overweight individuals with sleep apnoea: a randomised controlled trial (ELISA) (2023)
  • **** Yoga, immunity and COVID-19: a scoping review (2022)
  • 9 Effect of pranayama on perceived stress, well-being and quality of life of frontline healthcare professionals on COVID-19 duty: a quasi-randomised clinical trial (2024)
  • 10 Yoga practice (Sheetali Pranayama) on cognition in patients with hypertension: a randomised controlled study (2021)
  • **** Effects of Slow Breathing Exercises on Cardiac Autonomic Functions in Anxiety Disorder: A Randomised Controlled Trial (2026)
  • **** The Effect of Specific Techniques of Nasal Breathing [Pranayama] on Intra-Ocular Pressure in Normal Individuals: A Randomised Trial (2022)
  • 11 Yoga-based breathing and relaxation as adjunctive therapy for chronic migraine: a randomised controlled trial on clinical outcomes and autonomic regulation (2025)
  • 12 Effectiveness of pranayama for mental disorders: a systematic review and meta-analysis of randomised controlled trials (2025)
  • 13 The Effect of Breathing Yoga "Bhramari Pranayama" on Fatigue and Depression in Patients with Multiple Sclerosis: A Randomised Clinical Trial (2025)
  • 14 The combined effect of physical exercise, pranayama, and diet on fatigue in adult cancer patients undergoing chemotherapy: a randomised controlled trial (2024)
  • 15 Efficacy of Bhramari pranayama and Om chanting on asthma control, quality of life, and airway inflammation in asthmatic children: an open-label randomised controlled trial (2024)
  • 16 Effect of Pranayama on Perceived Stress, Well-Being and Quality of Life of Frontline Healthcare Professionals on COVID-19 Duty: A Quasi-Randomised Clinical Trial (2022)
  • 17 Randomised Controlled Trial on the Effect of Yoga on Anxiety Severity, Quality of Life, and Biomarkers in Individuals with Anxiety Disorder (2026)
  • 18 Effect of Yoga-Based Breathing Exercises on Pain, Fatigue, Insomnia, and Self-Efficacy in Individuals Undergoing Colorectal Cancer Surgery: A Randomised Controlled Trial (2026)

5. Unresolved Questions

  • Long-term effects: It remains unclear whether yoga produces sustained changes in clinical endpoints such as disease progression or quality of life.
  • Dose-response relationship: The intensity, duration, or frequency of exercises required to achieve specific effects remains uncertain.
  • Mechanisms: The physiological and psychological pathways of action are only partially understood, particularly in complex programmes.

Frequently Asked Questions

Can yoga be used as a standalone therapy for chronic pain?

The evidence is limited and contradictory. A frequently cited RCT demonstrates superiority over exercise therapy for chronic low back pain, while other studies find no significant differences. It is important to note that yoga was applied here as a multimodal programme (asanas, breathing exercises, meditation). For other types of pain, such as migraine or osteoarthritis, controlled studies are lacking. Safety is assured with proper instruction, but yoga is not a substitute for evidence-based pain management.

Which breathing techniques (Pranayama) are best studied?

Sheetali Pranayama and Bhramari Pranayama are the most frequently examined techniques. Studies investigate their effects on cardiovascular parameters (e.g., blood pressure, heart rate variability) and psychological stress (stress, anxiety), though results are inconsistent. Additionally, intervention protocols vary widely, complicating comparisons. Other techniques, such as Kapalabhati or Nadi Shodhana, have rarely been studied in controlled trials. Mechanistic research suggests autonomic regulatory processes, but the clinical relevance of these findings remains unclear.

Are there risks or contraindications for yoga?

Safety data primarily derive from studies involving oncological or cardiovascular patients and indicate low risks when properly instructed. However, systematic assessments of adverse effects are lacking. Potential risks include orthopaedic strain (e.g., in hypermobility) or cardiovascular events (e.g., in advanced heart failure). As specific contraindications have not been systematically investigated, its use in acute illnesses or severe neurological disorders should be assessed on an individual basis.

Sources

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    Effect of Sheetali pranayama on cardiac autonomic function among patients with primary hypertension - A randomized controlled trial
    Thanalakshmi J, Maheshkumar K, Kannan R, Sundareswaran L, Venugopal V, Poonguzhali S · 2020
  3. 3
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  6. 6
    Effect of six months pranayama training on stress-induced salivary cortisol response among adolescents-Randomized controlled study
    Maheshkumar K, Dilara K, Ravishankar P, Julius A, Padmavathi R, Poonguzhali S et al. · 2022
  7. 7
  8. 8
  9. 9
  10. 10
    Yoga practice (Sheetali Pranayama) on cognition in patients with hypertension: A randomized controlled study
    Jagadeesan T, Choudhary AK, Loganathan S, Rajendran K, Allu AR, Kuppusamy M · 2021
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Every statement on this page carries its evidence tier — proven, plausible or hypothesis — and leads to the original work. The decision in the individual case rests with the practitioner; we provide the connections.

International Health Research · https://ih-research.com/en/knowledge/yoga/ · Last updated: 2026-10-15