From Medical News Today
Health benefits of yoga
Scientific trials of varying quality have been published on the health benefits and medical uses of yoga. Studies suggest that yoga is a safe and effective way to increase physical activity and enhance strength, flexibility and balance. Yoga practice has also shown benefit in specific medical conditions, and we will look at this evidence and current scientific research below.
Scientists and medical doctors pursuing yoga-related research focus on its potential benefits as a technique for relieving stress and coping with chronic conditions or disabilities, as well as investigating its potential to help prevent, heal, or alleviate specific conditions, such as heart disease, high blood pressure, carpal tunnel syndrome, asthma, diabetes, and symptoms of menopause.
1) Anxiety and depression
Mind-body medical interventions are commonly used to cope with depression, and yoga is one of the most commonly used mind-body interventions. Systematic studies and meta-analyses have been carried out in order to assess the effectiveness of yoga for depression.
In one 9-week course of yoga, veterans were seen to experience significant reductions in anxiety, depression, and suicidal ideation. Mental health functioning scores were also improved, but pain intensity and physical health functionality did not show improvements.32
Elevated levels of cortisol (the stress hormone) are commonly seen in depression, and yoga has demonstrated an ability to relieve hypercortisolemia and reduce other parameters of stress. A study into the effects of yoga on cortisol and depression found that yoga might act at the level of the hypothalamus to create an ‘anti-stress’ effect by reducing cortisol levels, thereby helping to bring about relief in depression.
A systematic review and meta-analysis investigating yoga for depression examined 12 randomized controlled trials, including 619 participants. The researchers concluded that despite the methodological drawbacks of the included studies, yoga could be considered an ancillary treatment option for patients with depressive disorders and individuals with elevated levels of depression.
Results from a study suggest that yoga may be a promising way for adolescents to reduce MPA and perhaps even prevent it in the future. These findings also suggest a novel treatment modality that potentially might alleviate MPA and prevent the early disruption and termination of musical careers.
A systematic review of 9 studies regarding yoga as a complementary approach for osteoarthritis found positive changes in psychological or physiological outcomes related to arthritis.
The studies varied in length and not all of the studies used randomized controlled design; many had small sample sizes, different outcomes, and used non-standardized yoga interventions. Despite these limitations, the reviewers concluded that yoga appears to be a promising modality for arthritis.
In a study comparing people with asthma When comparing asthmatics in a yoga group and in a non-yoga control group with those in a control group, those in the yoga group had a significant improvement in a number of parameters suggesting improvements in symptoms of asthmas.
These parameters included an improvement in levels of the proportion of hemoglobin and the antioxidant superoxide, and a significant decrease was found in total leukocyte count (TLC) and differential leukocytes count in comparison to control group.
The yoga group had more significant improvements in biochemical variables than the control group. Results show that yoga can be practiced as adjuvant therapy with standard inhalation therapy for a better outcome of asthma.
However, a systematic review assessing the effectiveness of yoga as a treatment for asthma, concluded that there is insufficient quality evidence to support the belief that yoga alleviates asthma and that further, more rigorous trials are warranted.
4) Balance and falls
Falls amongst older people are a global health concern. Whilst falling is not a typical feature of aging, older people are more likely to fall and falls are a leading cause of death and disability.
Yoga and tai chi have shown potential to improve balance and prevent falls in older adults. They also have the potential to improve pain and quality of life.
In a 14-week program comparing yoga and tai-chi to usual care, yoga was associated with a slight decrease in the incidence of falls and a reduction in average pain scores in older adults. Although these changes were not statistically significant, the results showed positive changes to balance, pain and quality of life and a high level of interest through attendance amongst older participants.
The results support offering tai chi and yoga to older people who are frail and dependent with physical and cognitive limitations.
Another study observing body balance and postural control in young adults determined that a 5-month hatha yoga training program could improve postural control significantly in healthy adults.
5) Bipolar disorder
In a study of the benefits and risk of yoga in individuals with bipolar disorder, the participants reported positive emotional effects, particularly reduced anxiety, positive cognitive effects (e.g., acceptance, focus, or “a break from my thoughts”), or positive physical effects (e.g., weight loss, increased energy). Some respondents considered yoga to be significantly life changing. The most common negative effect of yoga was physical injury or pain.
Five respondents gave examples of specific instances where yoga practice increased their agitation or manic symptoms, while another five respondents gave examples of times that yoga increased depression or lethargy.
6) Breast cancer cognitive problems
Survivors of cancer often report cognitive problems, and people undergoing cancer treatment often experience decreases in physical activity. Although physical activity benefits cognitive function in non-cancer populations, evidence linking physical activity to cognitive function in survivors of cancer is limited.40
A study comparing a group with and without yoga intervention found that those who practiced yoga more frequently reported significantly fewer cognitive problems at a 3-month follow-up compared to those who practiced less frequently.
These findings suggest that yoga can effectively reduce cognitive problems in survivors of breast cancer and prompt further research on mind-body and physical activity interventions for improving cancer-related cognitive problems.
7) Breast cancer disability
Secondary arm lymphedema continues to affect at least 20% of women after treatment for breast cancer, along with pain and restricted range of motion requiring lifelong professional treatment and self-management.
A pilot trial was designed to investigate the effect of yoga on women with stage one breast cancer-related lymphedema. The 8-week yoga intervention reduced tissue induration of the affected upper arm and improved quality of life scores. Arm volume of lymphedema and extra-cellular fluid did not increase during the yoga intervention, but these benefits dissipated after the women stopped doing yoga, at which point arm volume of lymphedema increased.
Additional research of a longer duration and with higher levels of lymphedema and larger numbers is warranted before definitive conclusions can be made.
8) Cancer-related fatigue
Fatigue is one of the most frequently reported, distressing side effects reported by survivors of cancer and often has significant long-term consequences. Research indicates that yoga can produce invigorating effects on physical and mental energy, and thereby may improve levels of fatigue.
An 8-week yoga exercise program assessed whether yoga can decrease anxiety, depression and fatigue in patients with breast cancer. Fatigue was effectively reduced in the study but the intervention was not associated with a reduction in depression or anxiety.
The authors of the study conclude that oncology nurses should strengthen their clinical health education and apply yoga to reduce the fatigue experienced by patients with breast cancer who undergo adjuvant chemotherapy.
Another 12-week study found that restorative iyengar yoga was associated with reduced inflammation-related gene expression in breast cancer survivors with persistent fatigue. These findings suggest that a targeted yoga program may have beneficial effects on inflammatory activity in this patient population, with potential relevance for behavioral and physical health.
A systematic review of yoga interventions on fatigue in patients with cancer and survivors of cancer suggests that yoga interventions may be beneficial for reducing cancer-related fatigue in women with breast cancer; however, conclusions should be interpreted with caution as studies demonstrated varying levels of bias and inconsistent methodology.
9) Cardiovascular disease
A sedentary lifestyle and stress are major risk factors for cardiovascular disease. Since yoga involves exercise and is thought to help in stress reduction, it may be an effective strategy in the primary prevention of cardiovascular disease.
Across 11 identified trials with 800 participants, researchers found that the limited evidence in this field comes from small, short-term, low-quality studies. There is some evidence that yoga has favorable effects on diastolic blood pressure, high-density lipoprotein (HDL) cholesterol and triglycerides, while the effects on low-density lipoprotein (LDL) cholesterol were uncertain. These results should be considered as exploratory and interpreted with caution.
A further meta-analysis revealed evidence for clinically important effects of yoga on most biological cardiovascular disease risk factors. Despite methodological drawbacks of the included studies, yoga can be considered as an ancillary intervention for the general population and patients with increased risk of cardiovascular disease.
10) Chronic neck pain
Assessment of the effects of a 9-week yoga intervention on chronic nonspecific neck pain found that neck-related disabilities were improved for at least 12 months after intervention completion. Sustained yoga practice was deemed the most important predictor of long-term effectiveness.
11) Chronic heart failure
A meta-analysis of the effects of yoga in patients with chronic heart failure suggested that yoga compared with control had a positive impact on peak Vo2 (oxygen uptake, an indicator of exercise capacity) and health-related quality of life.
Yoga could be considered for inclusion in cardiac rehabilitation programs. Larger randomized controlled trials are required to further investigate the effects of yoga in patients with chronic heart failure.
A randomized controlled trial indicated that the addition of yoga therapy to standard medical therapy for heart failure patients has a markedly better effect on cardiac function and reduced myocardial stress measured using N terminal pro B-type natriuretic peptide in patients with stable heart failure.
Currently, several studies have assessed the effect of yoga training on the management of chronic obstructive pulmonary disease. Five randomized controlled trials involving 233 patients suggested yoga training has a positive effect on improving lung function and exercise capacity and could be used as an adjunct pulmonary rehabilitation program in COPD patients.
However, further studies are needed to substantiate these preliminary findings and to investigate the long-term effects of yoga training.
Research looking at the effects of selected asanas in iyengar yoga over 6 weeks showed a significant increase in flexibility. Specifically, the results of this research indicate that 6 weeks of single session yoga training may be effective in increasing flexibility in the hamstring and erector spinae (the muscles extending the vertebral column).
14) Gastroesophageal reflux disease (GERD)
A case report assessed the effects of yoga on gastroesophageal reflux disease (GERD). The researchers indicate regular and proper use of yoga along with over-the-counter or prescribed proton pump inhibitors (PPI) can control the severe symptoms of GERD and can avoid or delay the need for invasive procedures.
The case report showed that with the regular practice of kapalbhati and agnisar kriya along with PPI, patients with hiatal hernia had improvement in severe symptoms of GERD which were initially refractory (unresponsive) to PPI alone.
Effective stress management is a key part of managing blood pressure, and a number of systematic reviews have assessed the available evidence for yoga as a therapeutic tool for managing prehypertension and hypertension (elevated blood pressure). Researchers have found that yoga may be an effective adjunct treatment for hypertension, although further evidence is needed.
These reviews found that although yoga is associated with decreases in both systolic and diastolic blood pressure, its effects are minimal compared with exercise. The studies reviewed varied greatly in duration, methodology, and in the type of yoga practiced, and the researchers called for future research that focuses on high quality clinical trials along with studies on the mechanisms of action of different yoga practices.
The antihypertensive effects of yoga appear to be greater in people with cardiovascular disease, although people with normal blood pressure may also benefit.
16) Low back pain
Several studies suggest yoga may be effective for chronic low back pain and have shown that yoga intervention in populations with chronic low back pain may be more effective than usual care for reducing both pain and medication use.
A randomized controlled study investigating medical yoga, exercise therapy and self-care advice concluded that 6 weeks of uninterrupted medical yoga therapy is a cost-effective early intervention for non-specific low back pain, when patients adhere to treatment recommendations.
In another study, researchers investigated the effects of yoga on pain, brain-derived neurotrophic factor (BDNF), and serotonin in premenopausal women with chronic low back pain. BDNF and serotonin are considered mediators of nociceptive pain (i.e. pain felt due to tissue irritation or injury).
Participants practiced yoga three times a week for 12 weeks and at the end of the study had a decrease in pain as measured on a Visual Analog Scale (VAS). The VAS score increased in the control group who did not practice yoga. Back flexibility also improved in the yoga group, while serum BDNF increased and serum serotonin and depression scores remained the same in the yoga group.
The control group had a decrease in BDNF and serotonin levels as well as an increase in depression scores. The researchers propose that brain-derived neurotrophic factor may be one of the key factors mediating beneficial effects of yoga on chronic low back pain.
A similar trial monitored changes in pain intensity and health-related quality of life in nonspecific low back pain in those participating in iyengar yoga or general exercise. The results suggest iyengar yoga provides better improvement in pain reduction and quality of life compared to general exercise.
Virtual reality-based yoga programs such as Wii Fit Yoga have been shown to have positive effects on physical improvements in middle-aged female patients with low back pain. This program can be employed as a therapeutic medium for prevention and cure of low back pain.
A meta-analysis of randomized controlled trials regarding the use of yoga for chronic low back pain offers further confirmation that yoga may be an efficacious adjunctive treatment for chronic low back pain. However, the researchers were careful to note that a number of methodological concerns need to be addressed before any definitive conclusions can be drawn regarding yoga’s specific treatment effects or advantages over traditional exercise programs.
In a community-based interventional study, the quality of life in menopausal women was greatly improved after an 18-week course of yoga practice. The researchers concluded that yoga is an effective complementary health approach for those suffering menopausal symptoms.
18) Mental health
Physical activity has a positive effect on mental health and well-being. The aim of one study was to compare the effects of hatha yoga and resistance exercises on mental health and well-being in sedentary adults.
Hatha yoga improved fatigue, self-esteem, and quality of life, whilst resistance exercise training improved body image. Hatha yoga and resistance exercise decreased depression symptoms at a similar level.
Hatha yoga and resistance exercise may affect different aspects of mental health and well-being.
19) Metabolic syndrome
An explorative study investigated metabolic responses to mental stress and yoga practices in yoga practitioners, non-yoga practitioners and individuals with metabolic syndrome (a cluster of factors that increase a person’s risk for heart disease, diabetes, and stroke).
The results of the study support the findings of previous randomized trials that suggest regular yoga practice may mitigate against the effects of metabolic syndrome.
In a more recent study, 44% of the 84 patients with metabolic syndrome (MetS) who undertook a year-long yoga practice no longer met the diagnostic threshold for MetS. In the group practicing hatha yoga three times a week, 67% had a decreased number of MetS components after the year of yoga. However, some 15% of the patients had an increased number of MetS components.
The only factor that reached statistical significance was a decrease in the prevalence of central obesity; at the start of the study, 90.5% of those in the yoga group had central obesity, dropping to just 64.3% at the end of the intervention. The yoga group also demonstrated a trend towards a decrease in systolic blood pressure, and a decrease in resting heart rate.
A comprehensive study examining the effect of yoga on migraine showed significant clinical improvement in frequency and intensity of migraines in those taking part in yoga therapy. The researchers concluded that yoga therapy could be effectively incorporated as an adjuvant therapy in migraine patients.
Another study investigated the preventive effects of a three-month yoga intervention on endothelial function in patients with migraine. The study found that yoga exercises, as a complementary treatment beside pharmacological treatments, could be an effective way to improve vascular functions in migraineurs.
21) Mother and baby
Mother and baby yoga is becoming more and more popular as postpartum mothers discover the benefits of being able to “work out,” bond with their baby and relax, all in one session.
According to The Practicing Midwife, postnatal yoga can enhance feelings of calmness and a sense of well-being, helping mothers to improve and stabilize their emotional health and to bond with their baby. Additionally, yoga may help to strengthen the weakened pelvic floor and abdominal muscles and may even alleviate back and neck pain. For babies, yoga can aid digestion and alleviate colic, help to strengthen growing limbs, improve sleep patterns, and enhance their ability to interact with their mother and other people.
22) Oxidative stress
Hypertension, especially in the elderly, is a strong risk factor for cardiovascular mortality and morbidity. Oxidative stress has been implicated as one of the underlying causes of hypertension.
A study found yoga to be an effective means to reduce oxidative stress and to improve antioxidant defense in elderly hypertensive individuals.
In another, small study, researchers found that regular yoga practice could decrease oxidative stress and improve antioxidant levels, in addition to significantly increasing certain aspects of immune function and stress.
Young, healthy university students volunteered for the study and were assigned either to a control group (13) who did no yoga, or a yoga group (12) who practiced yoga with an instructor for 90 minutes once a week for 12 weeks, with daily home-based practice for the duration.
The researchers also noted that the yoga group had a significant increase in immune-related cytokines, such as interleukin-12 and interferon-gamma, suggesting immune benefits of yoga. The students practicing yoga also had significant reductions in levels of adrenalin and increased levels of serotonin compared with the control group, suggesting enhanced stress management.
23) Posttraumatic stress
More than a third of the approximately 10 million women with histories of interpersonal violence in the US develop posttraumatic stress disorder (PTSD).
A study exploring the efficacy of yoga to increase affect tolerance and to decrease PTSD symptomatology found yoga significantly reduced symptoms of PTSD and improved the functioning of traumatized individuals.
In a small pilot study, researchers assessed the potential benefits of a yoga program as an adjunctive therapy for improving PTSD symptoms in veterans with military-related PTSD. Twelve veterans took part in a 6 week yoga intervention held twice a week, and the researchers observed a significant improvement in PTSD hyperarousal symptoms and overall sleep quality as well as daytime dysfunction related to sleep.
The intervention was not associated with significant improvements in total PTSD, anger, or quality of life, but the researcher concluded that yoga may be an effective adjunctive therapy for some symptoms of PTSD in veterans.
Yoga is used for a variety of immunological, neuromuscular, psychological, and pain conditions. Recent studies indicate that it may be effective in improving pregnancy, labor, and birth outcomes.
The breathing and meditation techniques can help enhance health and relaxation for those who are pregnant, and support mental focus to aid childbirth. Some postures are chosen specifically to help encourage an optimal fetal position.
In a survey ascertaining the opinions, practices and knowledge about exercise, including yoga, during pregnancy:
- 86% of women responded that exercise during pregnancy is beneficial
- 83% felt it was beneficial to start prior to pregnancy
- 62% considered walking to be the most beneficial form of exercise
- 64% of respondents were currently exercising during pregnancy
- 51% exercised 2-3 times a week
- 65% considered yoga to be beneficial
- 40% had attempted yoga before pregnancy.
Another study tested the efficacy of yoga as an intervention for reducing maternal anxiety during pregnancy.
A single session of yoga reduced both subjective and physiological measures of state anxiety and the reduction in anxiety persisted at the final session of the intervention. Antenatal yoga seems to be useful for reducing women’s anxieties toward childbirth and preventing increases in depressive symptomatology.
Yoga group participants show fewer postpartum but not antepartum depressive symptoms than control group participants. Findings indicate that prenatal hatha yoga may improve current mood and may be effective in reducing postpartum depressive symptoms.
A systematic review of yoga in pregnancy showed that studies indicate that yoga may produce improvements in stress levels, quality of life, aspects of interpersonal relations, autonomic nervous system functioning, and labor parameters such as comfort, pain, and duration. However, they conclude that more randomized controlled trials are needed to provide more information regarding the utility of yoga interventions for pregnancy.
25) Restless legs syndrome
Restless legs syndrome is a common disorder that can cause serious sleep disturbance and have a significant adverse effect on quality of life.
In one study, women aged 32-66 years with restless legs syndrome completed 16 yoga classes over an 8-week period. At the end of the study, participants demonstrated striking reductions in symptoms of restless legs syndrome and decreased symptom severity. Symptoms were reduced to minimal/mild in all but one woman and no participant reported severe symptoms by week 8. Participants also showed significant improvements in sleep, perceived stress, and mood.58
The aging process is associated with physiological changes that affect sleep. In older adults, undiagnosed and untreated insomnia may cause impaired daily function and reduced quality of life. Insomnia is also a risk factor for accidents and falls that are the main cause of accidental deaths in older adults.
Compared with controls, the yoga group reported significant subjective improvements in a range of measures, including:
- Overall sleep quality
- Sleep efficiency
- Sleep latency and duration
- Self-assessed sleep quality
- General well-being
- Function in physical, emotional, and social roles.
Another study found that an 8-week yoga intervention in 20 people with chronic insomnia led to statistically significant improvements in sleep efficiency, total sleep time, total wake time, sleep onset latency (how long it takes to fall asleep), and wake time after sleep onset.
27) Stress management
Several studies have looked at yoga as a model for stress management. In a study observing the effects of 10 weeks of classroom-based yoga on cortisol and behavior in second and third-grade students, cortisol decreased significantly and students’ behavior improved. The results suggest that school-based yoga may be advantageous for stress management and behavior.
One study found that yoga may help children and young people cope with stress and, as a result, could contribute positively to balance in life, well-being, and mental health.
Another study evaluated the influence of hatha yoga practice on levels of distress in women about to begin a course of in vitro fertilization (IVF). Of the 143 female participants, 45 attended hatha yoga and 75 did not. Data suggest that psychological support and practice of hatha yoga before IVF is associated with distress reduction.
28) Urinary incontinence
Yoga has been shown to reduce inflammation and may help improve symptoms of urge urinary incontinence. More research is necessary to demonstrate the effectiveness of yoga to reduce urge urinary incontinence symptom burden and improve quality of life.
29) Weight management
A comparative controlled trial compared the effects of yoga and walking for weight management in overweight and obese adults.
Both groups showed a significant decrease in body mass index (BMI), waist circumference, hip circumference, lean mass, body water and total cholesterol. The yoga group increased serum leptin and decreased low-density lipoprotein (LDL) cholesterol. The walking group decreased serum adiponectin and triglycerides.
Both yoga and walking improved anthropometric variables and serum lipid profile in overweight and obese persons.
The prevalence of yoga research in western health care is increasing. The marked increase in volume indicates the need for more systematic analysis of the literature in terms of quality and results.
A new study suggests that for people with two of the most common forms of arthritis – osteoarthritis and rheumatoid arthritis – yoga may improve symptoms.
Yoga: downward dog increases eye pressure, risks for glaucoma patients
A new study in the journal PLOS One suggests certain poses increase eye pressure and present risks for individuals with glaucoma.
Yoga may ease symptoms for atrial fibrillation patients
People with paroxysmal atrial fibrillation may find that yoga helps them enjoy a better quality of life and reduce their blood pressure and heart rate. This was the main finding of a study published in the European Journal of Cardiovascular that compares patients with paroxysmal atrial fibrillation who practiced yoga with patients who did not.
Yoga may improve symptoms, quality of life for people with asthma
For people with asthma, yoga may help improve symptoms and overall quality of life, though further evidence of its possible benefits is warranted before yoga can be recommended for the respiratory condition. This is the conclusion of a new Cochrane Review, recently published in the Cochrane Library.