Yoga for Adults with Type 2 Diabetes: A Systematic Review of Controlled Trials

Table 2

Summary of study characteristics and major findings.

First author, year, and location	Tx duration	Study population	enrolled/completed (per group) [% retention]	Yoga intervention	Comparison condition	Assessment times	Major findings	PEDro scale score (range 0–10)
Nonrandomized controlled trials (NRCTs)
Dash, 2014, India [42]	40 days	Adults 40–60 yo w/DM2 for 0–10 y; Excl: BMI > 25; DM1; DM2 w/nephropathy, CAD, retinopathy, alcoholism; practicing any yoga; 37% F	60 (30Y, 30C) [100%]	Yoga (AS, PR, SH, and M): 30–40 min/d; + prescribed diet, oral meds	Prescribed diet, oral meds	Before and after: FBG, PPBG, A1c, TC, Tg, LDL, HDL, and VLDL	Yoga: Sig ↓ in FBG, PPBG, A1c, TC, Tg, LDL, VLDL, Sig ↑ HDL; C: Sig ↓ in FBG, PPBG, VLDL; Y vs. C: Sig ↓ in FBG, PPBG, A1c, TC.; TG, LDL, Sig ↑ HDL	4
Popli, 2014, India [43]	6 mos	Adults 30–60 yo w/DM2, no previous yoga experience; Excl: Pts already on oral hypoglycemic meds or insulin, w/alcoholism, BG > 300 mg/dL, or end-organ damage (e.g., retinal detachment, nephropathy, and peripheral neuropathy)	130 (80Y, 50C)	Yoga (AS, PR): 1 hr with yoga trainer, 5 d/wk for 1st month, and then continuing practice at home for remaining 5 mos	No treatment	Monthly: FBG; 3x/mo: PPBG, A1c	Yoga: Sig ↓ in FBG, PPBG, A1c; C: NS	1
Bindra, 2013, India [39]	up to 90 days	Adults 35–65 yo w/DM2 for not >10 y and no complications; Excl: those w/RA, cancer, TB, and MI and not willing to do yoga	100 (50Y, 50C) [100%]	Yoga (not described) + oral DM meds	Oral DM meds only	Before and after: FBG, A1c, TC, LDL, HDL, and Tg	Baseline yoga versus C: NS differences between the groups; After 90 days, Yoga versus C: Signif. differences between the groups in FBG, A1c, TC, LDL, HDL	5
Balaji, 2011, India [44]	3 mos	Uncomplicated DM2 Pts 40–55 yo w/DM duration 1–10 y	44 (22Y, 22C) [100%]	Yoga (AS, PR, SH): daily for 1 hr; subgroup T1 (): + oral drugs; subgroup T2 (): + oral drugs and insulin	22 controls	Before and after: FBG, PPBG, A1c, TC, Tg, LDL, HDL, and insulin requirement/day (subgroup T2), wt, BMI, W : H	Yoga T1: Sig ↓ in FBG, A1c, Tg, LDL, wt, BMI, W : H; Yoga T2: Sig ↓ in FBG, PPBG, A1c, Tg, LDL, wt, BMI, W : H, insulin/d; C: NS	2
Hegde, 2011, India [45]	3 mos	DM clinic Pts w/DM2; age: 40–75 y; Excl: smoking, alcoholism	123/120 (60Y, 63C); strat’d by complications [98%]	Yoga (AS, PR, and SH): at least 3 d/wk; + standard care	Standard care (given general oral and written information about diet and exercise)	Before and after: FBG, PPBG, A1c, oxidative stress (MDA, glutathione, SOD, Vit. C, and Vit. E), BMI, waist circumference, W : H, and BP	Y versus C: Sig ↓ in FBG, PPBG, A1c, BMI, MDA, Sig ↑ glutathione, Vit. C	4
Kyizom, 2010, India [46]	45 days; groups matched for age and sex	DM clinic Pts, 35–60 yo, w/uncomplicated DM2 from 2–10 y	60 (30Y, 30C) [100%]	Yoga (AS, PR, and SH): daily for 45 min/d; + standard care	Standard care	Before and after: FBG, PPBG, event-related evoked potentials at frontal (Fz), vertex (Cz), and parietal (Pz) areas, peak latencies, and baseline to peak amplitudes of N2 and P3	Yoga: Sig ↓ in FBG, PPBG; Sig ↓ in latency of N2 at Cz and P300 at all the montages (Fz, Cz, and Pz); Sig improvement in amplitude of wave N2 at Cz and P300 at Pz montage; C: NS	2
Malhotra, 2010, India [47]	40 days; controls matched on age and DM severity	Pts from endocrine metabolic clinic w/DM2 for 0–10 y, 30–60 yo, on recommended diet and oral DM meds; Excl: CAD, nephropathy, and proliferative retinopathy	106 (56Y, 50C)/64 (26Y, 38C) [60%]	Yoga (AS, PR, and SH): 40–60 min/d; + diet and DM meds	Standard care: meds, diet, and light exercises (walking)	Before and after: FBG, PPBG, TC, Tg, HDL, LDL, VLDL, MDA, and insulin; Wt, W : H, BMI, LBM, and BSA; SBP, DBP, HR, and QT interval; SVC, FEV1, FVC, FEV1 : FVC ratio, PEFR, and MVV; median nerve conduction velocity (m/sec), amplitude (mV), and latency (msec) measured proximally (at elbow) and distally (at wrist)	Yoga: Sig ↓ in FBG, TC, Tg, MDA, SBP, DBP, heart rate, W : H; Sig improvement in pulmonary, CV fxn, Sig ↑ in left hand nerve conduction velocity and amplitude (distal); C: Sig ↓ in LBM (worsening), nerve conduction amplitude (right proximal), Sig ↑ in Tg (worsening), insulin (in 4 pts), HR, PEFR; Y versus C: not analyzed	2
Mahapure, 2008, India [41]	6 wks	Pts 40–58 yo, w/DM2 on regular diet and antidiabetic drug regimen	40 (30Y, 10C) [100%]	Yoga (AS, PR, SH); 1 hr/d, every d except Sundays; + standard care	Standard care: diet and meds	Before and after: FBG, A1c, and SOD	Yoga: Sig ↓ in FBG, A1c, Sig ↑ SOD; C: NS; Y versus C: Sig ↓ in FBG, A1c, Sig ↑ SOD	3
Singh, 2008, India [48]	45 days	Pts 35–60 yo, w/uncomplicated DM2 for 1–10 y	60 (30Y, 30C) [100%]	Yoga (AS, PR, and SH): daily for 45 min/d; + standard care	Standard care (conventional meds)	Before and after: FBG, PPBG, A1c, TC, Tg, LDL, VLDL, HDL, insulin, wt, and BMI	Yoga: Sig ↓ in Wt, FBG, PPBG, insulin, TC, Tg, VLDL, LDL; Sig ↑ in HDL; C: Sig ↑ Wt; Y versus C: not given	2
Agte, 2004, India [40]	4 mos	Previously diagnosed DM2 Pts 45–65 yo; having stabilized glucose levels, and taking conventional prescribed medications; BMI: 25.4 (Y), 25.6 (C); 53% F	87 (57Y, 30C)/65 (35Y, 30C) [75%]	SKY + PR, AS, and M; interactive discussions on stress-free living; nutritional counseling w/emphasis on eating fresh fruits and vegetables; 6 d course	Without SKY training	Before and after: FBG, PPBG, A1c, TC, Tg, HDL, and MDA	Yoga: Sig ↓ in FBG, PPBG, TC, Tg, MDA; C: NS; Y versus C: not presented	1
Agrawal, 2003, India [49]	3 mos	Pts randomly selected from diabetes clinic (type of DM not specified, but background implies that study targeted DM2); Excl: Pts w/liver disease, alcoholism, malnutrition, thyrotoxicosis, TB, or who were noncooperative	200/154 (82Y, 72C) [77%]	Yogic lifestyle program: health rejuvenation exercises (5 min), AS (18 min), abdominal exercises (7 min), and R/M/PR (30 min); at least 5 d/wk + diet	Standard medical tx or standard home exercise program	Before and after: FBG, A1c, TC, HDL, LDL, VLDL, BP, BMI, W : H, QOL (satisfaction, impact, and worry), psychological assessment, self-evaluation, doses of metformin, glipizide, and insulin, BP, and renal function	Y versus C: Sig ↓ FBG, A1c, BMI, W : H, TC, LDL, VLDL, SBP, DBP; metformin, glipizide, and insulin doses; QOL satisfaction, impact, and worry scores, psychological assessment, and self-evaluation; Sig ↑ HDL	3
Malhotra, 2002, India [50]	40 days; controls matched on age, sex, SES, and DM severity	DM2 for 0–10 y; 30–60 yo; Excl: cardiac, renal, and proliferative retinal complications	40 (20Y, 20C) [100%]	Supervised yoga (AS, PR, and SH): daily for 30–40 min/d; + medication, diet	Medication, diet, and light exercise (walking)	Before and after 40-day treatment: median  nerve conduction velocity (m/sec), amplitude (mV), and latency (msec) measured proximally (at elbow) and distally (at wrist)	Yoga: Sig ↑ conduction velocity in left hand; C: Sig ↓ in amplitude at right elbow (proximal)	4
Khare, 1999, India [38]	3 mos, non-DM controls matched for age, sex	60 DM2 Pts (DM for 1-2 y) from DM clinics (in yoga/diet groups), 20 non-DM matched on age, sex; 40–70 y on vegetarian diet	80 (20, 20, 20, 20) [100%]	(1) Yoga: AS (3 poses, 2–5 min each) and SH (20 min) only; (2) Yoga + strict diet; Yoga: 2x/d	(1) No intervention (non-DM adults); (2) Strict diet alone (20 DM adults)	Baseline and 1, 2, and 3 months: BG, serum fructosamine, TC, and Wt	Yoga: after 3 mos, sig ↓ BG, Fruc, TC, and Wt; Yoga + diet: after 3 mos, sig ↓ BG, Fruc, TC, and Wt; Diet: after 3 mos, sig ↓ TC and Wt; non-DM, no tx: after 3 mos, NS	1
Randomized controlled trials (RCTs)
Habibi, 2013, Iran [51, 52]	12 wks	Women w/DM2, 45–60 yo, not taking insulin; without DM complications or hx of CVD	26 (16Y, 10C) [100%]	Yoga: 75 min, 3 d/wk	Standard care	Before and after: BP, FBG, F insulin, TC, HDL, LDL, leptin, Wt, and BMI	Y versus C: Sig ↓ in FBG, insulin, Tg	[52]
Jyotsna, 2012, India [53–56]	6 mos	Adults w/DM2 plus: lifestyle modification, A1c of 6–9%, and oral hypoglycemic agents for past 6 months; Excl: Pts w/retinopathy, glaucoma, uncontrolled HTN, CAD, overt complications of diabetes, and nephropathy; mean age (y): 49.92 ± 11.46 (yoga), 47.25 ± 10.80 (control)	120 (64Y, 56C) [100%]	Sudarshan Kriya yoga (SKY: a rhythmic cyclical breathing, preceded by PR); 3 d group training program followed by classes 1x/wk (long kriya) and daily home practice (short kriya) + standard care	Standard care (oral antidiabetic drugs and diet and exercise advice)	Before and 6 mos after tx: CAFTs, FBG, PPBG, and A1c; Before and 3 and 6 mos after tx: QOL (domains: (1) physical health, (2) psychological well-being, (3) social relationships, and (4) environment)	Yoga: Sig ↑ Symp fxn; C: NS; Y versus C: Sig ↑ overall cardiac autonomic fxn; Sig ↓ PPBG; Sig ↑ QOL: 3 mos after: domains 1 and 2 and total QOL; 6 mos after: domains 2 and 4 and total QOL	[53, 54]; 4 [55]; [56]
Nagarathna, 2012, India [57]	9 mos	Pts >25 yo with DM2 >1 y (FBG >120 mg% when dx), stable dose of oral hypoglycemic agents or insulin for at least 3 wks, no prior yoga practice, no major complications; mean age: 52.4 y; 31% F	277 (141Y, 136C)/173 (88Y, 85C) [62%]	Yoga (AS, PR, M, devotional sessions, and lectures): 1 hr/d, 5 d/wk for 12 weeks [cleansing techniques (kriyas) performed 1x/wk]; one 2 hr class/wk and 1 hr daily home practice for 9 mos	Exercises and walking designed to achieve a comparable intensity of physical exertion, nonyogic breathing exercises, supine rest, and lectures: 1 hr/d, 5 d/wk for 12 wks; one 2-hour class/wk and 1-hour daily home practice for 9 mos	Before and after: TC, Tg, HDL, LDL, VLDL, FBG, PPBG, A1c, and oral hypoglycemic medication requirement	Yoga: Sig ↓ meds, FBG, PPBG, A1c, Tg, TC, LDL, VLDL; Sig ↑ HDL; C: Sig ↓ PPBG, A1c, Tg, TC, VLDL; Y versus C: Sig ↓ meds, LDL; Sig ↑ HDL	6
Shantakumari, 2012, India [58, 59]	3 mos	Outputs with DM2 + HTN and dyslipidemia, 35–55 yo; Excl those w/known retinopathy, nephropathy, CAD, and cerebrovascular diseases; avg DM duration: 5–10 y; 48% F	100 (50Y, 50C) [100%]	Yoga: 1 hr daily; AS (30–35 min), PR (10 min), and M (15 min); + standard care	Standard care (oral hypoglycemic drugs, no yoga)	Before and after: FBG, PPBG, TC, HDL, LDL, Tg, Wt, W : H, BMI, SBP, and DBP	Yoga: Sig ↓ Wt, W : H, Tg, TC, LDL; C: Sig ↑ Wt	[59]; [58]
Subramaniyan, 2012, India [60]	15 days	Males ≥18 yo w/DM2 on standard care and medically eligible for walking/yoga per physician; age: 55% were 31–40 yo	20 [100%]	Yoga: 60 min (6-7 a.m.) daily; AS (~30 min), sun salutation (~6 min), SH (~25 min) + routine meds	Brisk walking: 60 min (6-7 a.m.) daily + routine meds	Before and after: FBG	Yoga: Sig ↓ in FBG; Walking: Sig ↓ in FBG	4
Vaishali, 2011, India [61, 62]	12 wks	Diabetic clinic Pts, >60 yo, w/DM2 >15 y and ≥1 metabolic risk factor (high FBG, pre-HTN, overwt/obese, high TC), on antidiabetic meds >10 y; Excl: uncontrolled HTN, severe neuropathy, hx of foot lesions, unstable proliferative retinopathy, and nephropathy	60/57 [95%]	Yoga (individualized AS, PR, and SH): 45–60 min under supervision, 6 d/wk	Educational group (general healthy lifestyle and exercise): 1x/mo	Before and after: FBG, A1c, TC, Tg, LDL, and HDL	Yoga: Sig ↓ in FBG, A1c, TC, Tg, LDL; Sig ↑ HDL; C: NS; Y versus C: Sig ↓ in A1c, FBG, TC, Tg, LDL; Sig ↑ HDL	[61]; 6 [62]
Pardasany, 2010, India [63]	12 wks	Adults w/DM2, 40–60 yo; Excl: hx of renal disease, arthritis, HBP, intermittent claudication, foot injury or ulcers, breathlessness, and cardiac disease; 38% F	45 (15, 15, 15) [100%]	Hatha yoga (12 AS and 6/7 PR): 3x/wk; oral hypoglycemic meds	(1) Yang-style tai chi (TC, 24 forms): 3x/wk, oral hypoglycemic meds; (2) Oral hypoglycemic meds, no exercise (C)	Before and after: FBG, PPBG, A1c, TC, and LDL	Yoga: Sig ↓ FBG, PPBG, A1c, TC, LDL; TC: Sig ↓ FBG, PPBG, A1c, TC, LDL; C: NS; Y versus C: Sig ↓ FBG, PPBG, TC, LDL; TC versus C: Sig ↓ FBG, PPBG, A1c, TC; Tai chi versus Y: NS
Amita, 2009, India [64]	Up to 90 days	Middle aged (35–65 yo), DM2 Pts on oral hypoglycemics; Excl: >200 mg/dL FBG, >300 mg/dL PPBG; hx of DM complications or other systemic conditions; 29% F	41 (20Y, 21C) [100%]	Yoga nidra (deep relaxation): 45 min, daily	Standard care (no yoga)	Every 30 days: FBG, PPBG, and symptoms related to DM (i.e., insomnia, palpitations, sweating, distress, headache, and anxiety)	Yoga: Sig ↓ FBG (60 and 90 d), PPBG (90 d), total symptoms (insomnia, distress, etc. after 3 mos); C: not given
Skoro-Kondza, 2009, UK (London) [65]	12 wks	Adults (>18 yo) w/DM2, not on insulin; most well-controlled (A1c ); mean duration of DM2 (y): 30 ± 5; mean age (y): 60 ± 10; nonwhite: 55% at one site, 40% at the other site; 61% F	59 [100%]	Yoga (PR, AS, and SH): 90 min class, 3x/wk	Wait list (both groups given leaflets on healthy lifestyle and encouraged to exercise)	Before and after and six months later: A1c, wt, waist circumference, W : H, BMI, TC, LDL, Tg, HDL, SBP, and DBP (used to calculate cardiovascular risk score); diabetes-related QOL, and self-efficacy.	Yoga: NS; C: NS: Y versus C: NS; Note:Quantitative data provided only for A1c
Gordon, 2008, Cuba [66–68]	24 wks, age and sex matched controls	Pts 40–70 yo w/DM2 from 1–10 y, w/at least 3 mos of training in DM education, exercise, diet, and medication according to IDF recommendations; no severe complications, nonsmoker, nonalcoholic	231 (77 Pts: 62 females, 15 males per group) [100%]	Yoga: PR (20 min), warm-up exercises (25 min), AS (60 min), and SH (15 min); 1 class/wk for 24 wks plus home yoga exercise (followed IDF criteria, with yoga as exercise)	(1) PT: warm-up exercises (15 min), aerobic walking (30 min), flexibility exercises (20 min), aerobic dance (20 min), games (25 min), warm-down (10 min); 1 class/wk for 24 wks plus home exercise 3-4x/wk (followed IDF criteria); (2) Control: tx plan as per their doctors, no active exercise tx	Baseline and 3 and 6 mos: FBG, A1c, insulin, TC, Tg, HDL, LDL, VLDL, BMI, MDA, PLA2 activity, POX, and SOD and catalase activity; microalbuminuria, creatinine; cortisol, TSH, T3, and T4	Yoga: 3 mos: Sig ↓ FBG, TC; 6 mos: Sig ↓ FBG, A1c, TC, VLDL, microalbuminuria, MDA; Sig ↑ SOD; PT: 3 mos: Sig ↓ FBG, TC; 6 mos: Sig ↓ FBG, TC, VLDL, microalbuminuria, MDA; Sig ↑ SOD; C: 3 mos: NS; 6 mos: NS; Y versus C: 3 mos: Sig ↓ FBG, A1c, TC; 6 mos: Sig ↓ FBG, A1c, TC, MDA, BMI, microalbuminuria, Sig ↑ % insulin receptor binding; PT versus C: 3 mos: Sig ↓ FBG, A1c, TC; 6 mos: Sig ↓ FBG, A1c, TC, MDA, BMI, microalbuminuria, Sig ↑ % insulin receptor binding	[66, 67]; [68]
Céspedes, 2002, Cuba [69]	12 mos	DM2 patients, 50–70 y, DM duration 2–5 y, without malnutrition or severe complications, in good mental health	40 (22 Y, 18 C) [100%]	Moderate intensity yoga (PR, AS): 60  min class, 3x/wk + lifestyle advice, soybean-rich diet	Moderate intensity aerobic exercise: 60 min class, 3x/wk + lifestyle advice, soybean-rich diet	Before and after: BG, TC, HDL, LDL, Tg, and creatinine	Yoga: Sig ↓ TC, LDL, Tg, creatinine; Sig ↑ HDL; PT: Sig ↓ TC, LDL, Tg, creatinine; Sig ↑ HDL; Y versus C: Sig ↓ TC, LDL, Tg, creatinine; Sig ↑ HDL	5
Monro, 1992, UK [70]	12 wks	DM2 controlled with meds (; yoga group = 8) or diet (); Excl: end stage liver or kidney disease or congestive cardiac failure; age (y): 45–67	21 (11Y, 10C) [100%]	Yoga (PR, AS, and R) + standard care: 90 min, classes offered 5x/wk (most attended classes 1-2x/wk and practiced at home 1-2x/wk)	Standard care (continuing on medication, diet)	Before and after: FBG and A1c	Y versus C: Sig ↓ in A1c, FBG

Assumed (retention not specifically reported), adherence very low, adherence moderate, adherence excellent, and score from PEDro database.
A1c: glycosylated hemoglobin A1c, AHA: American Heart Association, AS: yoga asanas or postures, avg: average, BF: biofeedback, BP: blood pressure, BSA: body surface area, C: control, CAD: coronary artery disease, CAFT: cardiac autonomic function tests, cal: calorie, Clin: clinical, comp: composition, CVD: cardiovascular disease, d: day, DM: diabetes mellitus, Excl: excluded, F: female, FBG: fasting blood glucose, FEV1: forced expiratory value in first second, FVC: forced vital capacity, h: hour, HDL: high density lipoprotein, HR: heart rate, HTN: hypertension, hx: history, IFN: interferon gamma, a cytokine critical for innate and adaptive immunity against viral and intracellular bacterial infections and for tumor control, IR: insulin resistance (markers of), KR: kriyas or cleansing exercises, LBM: lean body mass, LDL: low density lipoprotein, M: meditation, MDA: malondialdehyde, MI: myocardial infarction, mo: month, MVV: maximal voluntary ventilation, PEFR: peak expiratory flow rate, PLA2: phospholipase A2, PMR: progressive muscle relaxation, POX: protein oxidation, PPBG: postprandial blood glucose, PR: pranayama or yogic breathing exercises, QOL: quality of life, R: relaxation poses (nonspecified), RA: rheumatoid arthritis, Resid: residential, SH: shavasana or corpse pose, a traditional yoga relaxation pose, Sig: significant, SNS/PNS: markers of sympathetic/parasympathetic activation, including heart rate and catecholamine levels, SOD: superoxide dismutase, SVC: slow vital capacity, TB: tuberculosis, TC: total cholesterol, Tg: triglycerides, veg: vegetarian, VLDL: very low density lipoprotein, W : H: waist-hip ratio, wk: week, wt: weight, y: years, and yo: years old.