Yoga is a mindful movement practice that originates from India. It includes meditation, as well as a combination of positions, strengthening, and breathing exercises. The practice focuses on reconnecting the participant with their mind and body and is regarded as a form of physical, mental, and spiritual development.
Alongside this, yoga encourages the adoption of several lifestyle habits such as moderation in diet and abstinence from smoking and alcohol. This multi-dimensional aspect of yoga has extended to not only the maintenance of health but also the prevention of disease.
Among the health benefits, the practice of yoga has been linked to several health benefits that include decreasing chronic pain, stabilization of blood pressure, and stress reduction. Supportive data also suggest that yoga improves, strength, flexibility, breathing, balance, spine and mental health, and blood flow.
The effect of yoga on pain
Yoga has also been shown to be helpful for pain conditions. In a systematic review of yoga interventions, nine of 10 randomized controlled trials suggested that yoga leads to a significantly greater reduction in pain compared to the control interventions compared (standard care, self-care, therapeutic exercises, touch, and manipulation, or no intervention).
Yoga for the prevention of cardiovascular disease
Yoga has also been associated with improvements in several cardiovascular risk factors. The cardioprotective effects of yoga are believed to be mediated through stress reduction.
Stress is orchestrated through the hypothalamic-pituitary-adrenal axis, which culminates in hormonal secretion such as cortisol, glucagon, renin and angiotensin, and pro-inflammatory cytokines.
The physiological effect of the hormonal release includes increased blood pressure levels, hyperglycemia, and a pro-atherogenic effect (tending to promote the formation of fatty deposits in the arteries). In addition, increased heart rate and myocardial workload occur, alongside platelet aggregation and the production of a prothrombotic (increased risk of blood clots in vessels) environment.
Slow breathing and meditation which are included as part of yoga practices, can promote the activation of the parasympathetic nervous system; in turn, this may increase the variability of the heart rate to improve vascular tone.
Yoga may also reduce the level of dopamine and increase serotonin; this has been linked to improvements to mental and physical health. Moreover, the practice has also been shown to reduce plasma levels of inflammatory markers such as interleukin (IL) 6 C reactive protein as well as markers of oxidative stress.
Relative to other forms of exercise, yoga practices demonstrate equal or superior effects in improvements to several health outcomes which include ultra gnomic function, stress, antioxidant status, as well as patient recorded outcomes unrelated to physiological fitness. These include anxiety and depression, quality of life, and pain.
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Yoga and mental health
Several randomized controlled trials have reported beneficial effects of yoga interventions for the treatment of depressive symptoms. However, the data is insufficient to conclude whether there is a substantial clinical justification to consider yoga as a treatment for depression, particularly as the effect of yoga interventions as compared to active controls is less conclusive.
With regards to fatigue, a systematic review of 19 randomized controlled trials evaluating the effect of yoga on fatigue showed a small positive effect come up with a standard mean difference (SMD) of 0.28. An SMD value in the range 0.3- 0.5 can be regarded as small, 0.5- 0.8 as moderate, and >0.8 as large.
In anxiety, most studies describe the beneficial effects of yoga interventions, particularly when they are compared to passive controls as well as active controls such as relaxation response or drug therapy.
A single review article examining the affective yoga for the treatment of post-traumatic stress disorder (PTSD) has shown that yoga practice was reported to significantly reduce symptoms; self-reported symptoms of stress and respiration rate were analyzed in response to a natural disaster. In the context of combat and terrorism, a review has suggested a possible role of yoga in managing PTSD, although cites the need for greater long-term study.
Yoga vs other physical exercise interventions
Compared to inactive controls (i.e., education booklets), small to moderate significant effects favoring yoga were found for lower limb strength, depression, balance, lower body flexibility, perceived mental health, perceived physical health, sleep quality, and vitality.
Relative to active controls such as walking and aerobics yoga also elicits significant small to moderate effects were also found for lower body strength, lower body flexibility, and depression. This effect is also seen in elderly populations.
There are several areas in which yoga may be beneficial, however, more research is required to establish more definitive links between the health effects of yoga and particular health outcomes. Yoga is a therapeutic intervention that is only recently been used as such, that full studies are relatively few. Further investigations are warranted as there is a possible link between the underlying psychophysiological effects and positive health outcomes.
Nonetheless, yoga is promoted as part of physical activity policies worldwide owing to its multimodal benefits (improving muscle strength, balance, and flexibility) that produce measurable and perceived improvements in physical and mental wellbeing.
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