There is evidence in the archeological record that yoga has been practiced by humans for at least 5,000 years. Whereas this would constitute sufficient evidence for most folks to consider it a practice with real health benefits, as its millions of practitioners widely claim, skeptics say otherwise. They require any activity deemed to be of therapeutic value run the gauntlet of randomized, controlled clinical trials before it is fully accepted within the conventional medical system.
This tendency towards scientism in medicine, or what some call medical monotheism, runs diametrically opposed to the standards of lived-experience – so called "subjectivity" – or anecdotal experience (learning from the experience of others) which is what the majority of the world uses to determine if something has value, or is worth doing or not.
Yoga, of course, is no longer exclusively practiced by a particular religious group. It is considered a form of low-impact exercise and stress-reduction, and is estimated to be practiced by 20 million people in the US alone. This burgeoning interest among Westerners happens to be why so much human clinical research has now been performed on yoga. The US National Library of Medicine's bibliographic database shows that in 1968, seven studies were published on yoga. This year, there have been over 250. So much research, in fact, has accumulated that even systematic reviews of the literature have now been published.
Take a recently published systematic review in the Clinical Journal of Pain where an evaluation of ten randomized controlled trials found patients with chronic low back pain found "short-term effectiveness and moderate evidence for long-term effectiveness of yoga for chronic low back pain."[i]
The meta-analysis sits comfortably on the top of the pyramid of truth of "evidence-based" medicine. Once confirmation has occurred at these heights, few can accuse such an intervention of "quackery" without indicting the very holy grail of modern medicine itself.
So, what other human clinical research now confirms the value of yoga in the prevention and treatment of disease? We have found evidence supporting the use of yoga in as many as 70 distinct disease categories, all of which can be viewed on our Yoga Health Benefits page, and with 7 listed below:
- Type 2 Diabetes: Yoga has been found to reduce blood sugar and drug requirements in patients with type 2 diabetes.[ii] [iii] Additional benefits for type 2 diabetics include the reduction of oxidative stress,[iv] improved cognitive brain function,[v] improving cardiovascular function,[vi] and reducing body mass index, improved well-being and reduced anxiety.[vii]
- Asthma: There are now four clinical studies indicating that yoga practice improves the condition of those with bronchial asthma.[viii] [ix] [x] [xi]
- Elevated Cortisol (Stress): Yoga practice has been found to decrease serum cortisol levels which have been correlated with alpha wave activation.[xii] Yoga also compares favorably in this respect to African dance, the latter of which raises cortisol.[xiii] Women suffering from mental stress, including breast cancer outpatients undergoing adjuvant radiotherapy, have been found to respond to yoga intervention with lowered cortisol levels, as well as associated mental stress and anxiety reduction.[xiv] [xv]
- Fibromyalgia: There are three studies indicating that yoga improves the condition of patients suffering from fibromyalgia.[xvi] [xvii] [xviii]
- High Blood Pressure: Yoga has been found to reduce blood pressure in patients with prehypertension to stage 1 hypertension.[xix] Yoga has also been found to reduce blood pressure in more severe conditions, such as HIV-infected adults with cardiovascular disease.[xx] Yogic breathing is one of the most effective forms of yoga for this health condition, with both fast and slow-breathing exercises having value.[xxi]
- Obsessive-Compulsive Disorder: Yoga has been found to be efficacious in improving obsessive-compulsive behavior.[xxii] [xxiii]
- Computer Eye Strain: Yoga practice reduced visual discomfort in professional computer users.[xxiv]
Nonetheless, it is clear that yoga has come of age. Ancient wisdom is finding renewed confirmation by men and women in lab coats, who themselves could stand to loosen up and throw down a sun salutation or two. Considering the aforementioned "scientific research" available today, they might now be more inclined to do so.
- [i] Holger Cramer, Romy Lauche, Heidemarie Haller, Gustav Dobos. A Systematic Review and Meta-analysis of Yoga for Low Back Pain. Clin J Pain. 2012 Dec 14. Epub 2012 Dec 14. PMID: 23246998
- [ii] V V Bulavin, V M Kliuzhev, L M Kliachkin, Lakshmankumar, N D Zuikhin, T N Vlasova. [Elements of yoga therapy in the combined rehabilitation of myocardial infarct patients in the functional recovery period]. Vopr Kurortol Fizioter Lech Fiz Kult. 1993 Jul-Aug(4):7-9. PMID: 8236936
- [iii] S Amita, S Prabhakar, I Manoj, S Harminder, T Pavan. Effect of yoga-nidra on blood glucose level in diabetic patients. Indian J Physiol Pharmacol. 2009 Jan-Mar;53(1):97-101. PMID: 19810584
- [iv] Shreelaxmi V Hegde, Prabha Adhikari, Shashidhar Kotian, Veena J Pinto, Sydney D'Souza, Vivian D'Souza. Effect of 3-Month Yoga on Oxidative Stress in Type 2 Diabetes With or Without Complications: A controlled clinical trial. Diabetes Care. 2011 Aug 11. Epub 2011 Aug 11. PMID: 21836105
- [v] Tenzin Kyizom, Savita Singh, K P Singh, O P Tandon, Rahul Kumar. Effect of pranayama&yoga-asana on cognitive brain functions in type 2 diabetes-P3 event related evoked potential (ERP). Indian J Med Res. 2010 May;131:636-40. PMID: 20516534
- [vi] Savita Singh, V Malhotra, K P Singh, S V Madhu, O P Tandon. Role of yoga in modifying certain cardiovascular functions in type 2 diabetic patients. Prog Neuropsychopharmacol Biol Psychiatry. 2002 Jun;26(5):855-60. PMID: 15636309
- [vii] Madhu Kosuri, Gumpeny R Sridhar. Yoga practice in diabetes improves physical and psychological outcomes. Metab Syndr Relat Disord. 2009 Dec;7(6):515-7. PMID: 19900155
- [viii] R Nagarathna, H R Nagendra. Yoga for bronchial asthma: a controlled study. Br Med J (Clin Res Ed). 1985 Oct 19;291(6502):1077-9. PMID: 3931802
- [ix] R Jevning, A F Wilson, J M Davidson. Adrenocortical activity during meditation. Horm Behav. 1978 Feb;10(1):54-60. PMID: 350747
- [x] Candy Sodhi, Sheena Singh, P K Dandona. A study of the effect of yoga training on pulmonary functions in patients with bronchial asthma. Indian J Physiol Pharmacol. 2009 Apr-Jun;53(2):169-74. PMID: 20112821
- [xi] H R Nagendra, R Nagarathna. An integrated approach of yoga therapy for bronchial asthma: a 3-54-month prospective study. J Asthma. 1986;23(3):123-37. PMID: 3745111
- [xii] T Kamei, Y Toriumi, H Kimura, S Ohno, H Kumano, K Kimura. Decrease in serum cortisol during yoga exercise is correlated with alpha wave activation. Percept Mot Skills. 2000 Jun;90(3 Pt 1):1027-32. PMID: 1088379
- [xiii] Jeremy West, Christian Otte, Kathleen Geher, Joe Johnson, David C Mohr. Effects of Hatha yoga and African dance on perceived stress, affect, and salivary cortisol. J Vasc Surg. 2001 Sep;34(3):474-81. PMID: 15454358
- [xiv] Andreas Michalsen, Paul Grossman, Ayhan Acil, Jost Langhorst, Rainer Lüdtke, Tobias Esch, George B Stefano, Gustav J Dobos. Rapid stress reduction and anxiolysis among distressed women as a consequence of a three-month intensive yoga program. Med Sci Monit. 2005 Dec;11(12):CR555-561. Epub 2005 Nov 24. PMID: 16319785
- [xv] H S Vadiraja, Rao M Raghavendra, Raghuram Nagarathna, H R Nagendra, M Rekha, N Vanitha, K S Gopinath, B S Srinath, M S Vishweshwara, Y S Madhavi, B S Ajaikumar, Bilimagga S Ramesh, Rao Nalini, Vinod Kumar. Effects of a yoga program on cortisol rhythm and mood states in early breast cancer patients undergoing adjuvant radiotherapy: a randomized controlled trial. Integr Cancer Ther. 2009 Mar;8(1):37-46. Epub 2009 Feb 3. PMID: 19190034
- [xvi] James W Carson, Kimberly M Carson, Kim D Jones, Robert M Bennett, Cheryl L Wright, Scott D Mist. A pilot randomized controlled trial of the Yoga of Awareness program in the management of fibromyalgia. Pain. 2010 Nov;151(2):530-9. PMID: 20946990
- [xvii] Kathryn Curtis, Anna Osadchuk, Joel Katz. An eight-week yoga intervention is associated with improvements in pain, psychological functioning and mindfulness, and changes in cortisol levels in women with fibromyalgia. J Pain Res. 2011 ;4:189-201. Epub 2011 Jul 26. PMID: 21887116
- [xviii] Gerson D da Silva, Geraldo Lorenzi-Filho, Lais V Lage. Effects of yoga and the addition of Tui Na in patients with fibromyalgia. J Altern Complement Med. 2007 Dec;13(10):1107-13. PMID: 18166122
- [xix] Debbie L Cohen, Leanne T Bloedon, Rand L Rothman, John T Farrar, Mary Lou Galantino, Sheri Volger, Christine Mayor, Phillipe O Szapary, Raymond R Townsend . Iyengar Yoga versus Enhanced Usual Care on Blood Pressure in Patients with Prehypertension to Stage I Hypertension: a Randomized Controlled Trial. Evid Based Complement Alternat Med. 2009 Sep 4. Epub 2009 Sep 4. PMID: 19734256
- [xx] W T Cade, D N Reeds, K E Mondy, E T Overton, J Grassino, S Tucker, C Bopp, E Laciny, S Hubert, S Lassa-Claxton, K E Yarasheski. Yoga lifestyle intervention reduces blood pressure in HIV-infected adults with cardiovascular disease risk factors. HIV Med. 2010 Jan 5. Epub 2010 Jan 5. PMID: 20059570
- [xxi] Monika Mourya, Aarti Sood Mahajan, Narinder Pal Singh, Ajay K Jain. Effect of slow- and fast-breathing exercises on autonomic functions in patients with essential hypertension. J Altern Complement Med. 2009 Jul;15(7):711-7. PMID: 19534616
- [xxii] D S Shannahoff-Khalsa, L R Beckett. Clinical case report: efficacy of yogic techniques in the treatment of obsessive compulsive disorders. Int J Neurosci. 1996 Mar;85(1-2):1-17. PMID: 8727678
- [xxiii] D S Shannahoff-Khalsa, L E Ray, S Levine, C C Gallen, B J Schwartz, J J Sidorowich. Randomized controlled trial of yogic meditation techniques for patients with obsessive-compulsive disorder. CNS Spectr. 1999 Dec;4(12):34-47. PMID: 18311106
- [xxiv] Shirley Telles, K V Naveen, Manoj Dash, Rajendra Deginal, N K Manjunath. Effect of yoga on self-rated visual discomfort in computer users. Head Face Med. 2006;2:46. Epub 2006 Dec 3. PMID: 17140457