title: A large-scale survey of adverse events experienced in yoga classes.
abstract: BACKGROUND
  Yoga is a representative mind-body therapy of complementary and alternative medicine. In Japan, yoga is practiced widely to promote health, but yoga-associated adverse events have also been reported. To date, the frequencies and characteristics of yoga-related adverse events have not been elucidated. This study was conducted to elucidate the frequencies and characteristics of adverse events of yoga performed in classes and the risk factors of such events.
  
  
  METHODS
  The subjects were 2508 people taking yoga classes and 271 yoga therapists conducting the classes. A survey for yoga class attendees was performed on adverse events that occurred during a yoga class on the survey day. A survey for yoga therapists was performed on adverse events that the therapists had observed in their students to date. Adverse events were defined as "undesirable symptoms or responses that occurred during a yoga class".
  
  
  RESULTS
  Among 2508 yoga class attendees, 1343 (53.5%) had chronic diseases and 1063 (42.3%) were receiving medication at hospitals. There were 687 class attendees (27.8%) who reported some type of undesirable symptoms after taking a yoga class. Musculoskeletal symptoms such as myalgia were the most common symptoms, involving 297 cases, followed by neurological symptoms and respiratory symptoms. Most adverse events (63.8%) were mild and did not interfere with class participation. The risk factors for adverse events were examined, and the odds ratios for adverse events were significantly higher in attendees with chronic disease, poor physical condition on the survey day, or a feeling that the class was physically and mentally stressful. In particular, the occurrence of severe adverse events that interfered with subsequent yoga practice was high among elderly participants (70 years or older) and those with chronic musculoskeletal diseases.
  
  
  CONCLUSIONS
  The results of this large-scale survey demonstrated that approximately 30% of yoga class attendees had experienced some type of adverse event. Although the majority had mild symptoms, the survey results indicated that attendees with chronic diseases were more likely to experience adverse events associated with their disease. Therefore, special attention is necessary when yoga is introduced to patients with stress-related, chronic diseases.
authors.affiliation: Faculty of Arts and Science, Kyushu University, Fukuoka, 816-8581 Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Matsushita
authors.affiliation: Department of Psychosomatic Medicine, Graduate School of Medical Sciences, Fukuoka, Japan.
authors.forename: Takakazu
authors.initials: T
authors.lastname: Oka
keywords: Adverse event; Large-scale survey; Risk factor; Stress; Yoga
references.citation: Sleep Med. 2011 May;12(5):512-7
references.pmid: 21489869
references.citation: Psychiatry (Edgmont). 2010 Aug;7(8):20-32
references.pmid: 20877530
references.citation: Biopsychosoc Med. 2014 Dec 11;8(1):27
references.pmid: 25525457
references.citation: Int J Yoga. 2012 Jul;5(2):92-101
references.pmid: 22869991
references.citation: Am J Psychiatry. 2007 Nov;164(11):1761
references.pmid: 17974947
references.citation: PLoS One. 2013 Oct 16;8(10):e75515
references.pmid: 24146758
references.citation: J Altern Complement Med. 2010 Aug;16(8):899-905
references.pmid: 20624101
references.citation: Am Surg. 2012 Aug;78(8):E361-3
references.pmid: 22856477
references.citation: Am J Emerg Med. 2009 Sep;27(7):899.e1-2
references.pmid: 19683130
references.citation: J Gerontol Nurs. 2012 Jul;38(7):26-35; quiz 36-7
references.pmid: 22715961
references.citation: Pain. 2005 May;115(1-2):107-17
references.pmid: 15836974
references.citation: AJR Am J Roentgenol. 2012 Aug;199(2):413-8
references.pmid: 22826405
references.citation: Evid Based Complement Alternat Med. 2012;2012:294058
references.pmid: 22474497
references.citation: Ophthalmic Surg Lasers Imaging. 2008 Jul-Aug;39(4):339-40
references.pmid: 18717444
references.citation: J Pain. 2012 Nov;13(11):1122-30
references.pmid: 23117107
references.citation: Br J Ophthalmol. 2007 Oct;91(10):1413-4
references.pmid: 17895421
references.citation: J Bodyw Mov Ther. 2010 Jan;14(1):50-4
references.pmid: 20006289
references.citation: Arch Ophthalmol. 1995 Nov;113(11):1360-2
references.pmid: 7487590
references.citation: Adv Ther. 2006 Nov-Dec;23(6):921-5
references.pmid: 17276961
references.citation: Arch Intern Med. 2011 Dec 12;171(22):2019-26
references.pmid: 22025101
references.citation: Clin J Oncol Nurs. 2008 Feb;12(1):125-30
references.pmid: 18258582
references.citation: Int Dent J. 2007 Jun;57(3):184-6
references.pmid: 17695740
references.citation: Cornea. 2010 Aug;29(8):952; author reply 952-3
references.pmid: 20508504
references.citation: J Orthop Surg (Hong Kong). 2008 Dec;16(3):378-80
references.pmid: 19126911
references.citation: Br J Sports Med. 2007 Oct;41(10):688-90
references.pmid: 17496071
references.citation: Altern Ther Health Med. 2009 Nov-Dec;15(6):18-27
references.pmid: 19943573
references.citation: BMC Res Notes. 2014 Mar 24;7:172
references.pmid: 24661723
references.citation: Ann Intern Med. 2005 Dec 20;143(12):849-56
references.pmid: 16365466
references.citation: Indian J Ophthalmol. 2009 Jan-Feb;57(1):69-70
references.pmid: 19075418
references.citation: Emerg Med J. 2007 Mar;24(3):231
references.pmid: 17351243
references.citation: Chest. 2004 May;125(5):1951-2
references.pmid: 15136413
references.citation: Oncology (Williston Park). 2010 Aug;24(9):851
references.pmid: 20923043
references.citation: Altern Ther Health Med. 2006 Jan-Feb;12(1):40-7
references.pmid: 16454146
references.citation: Pain Pract. 2013 Jan;13(1):68-75
references.pmid: 22448849
references.citation: Ann Intern Med. 2011 Nov 1;155(9):569-78
references.pmid: 22041945
references.citation: Neurol Sci. 2013 Mar;34(3):393-6
references.pmid: 22526771