The background of yoga has its origin in ancient Indian philosophy. In contemporary society we can observe many schools or types of yoga. Each having its own specific emphasis regarding body postures, breathing techniques, relaxation technics, and meditation practices. That nurture awareness and state of consciousness. The application of yoga as a therapeutic means, take advantage of the number of psychological and physiological benefits. Yoga exercises may increase man flexibility, strength, coordination while the breading and meditation practices may silent the mind, hence evoke greater awareness and diminish anxiety, reduce distress, and thus enhance quality of life. Despite of growing body of clinical research on the therapeutic effects of yoga, there is still a lack of evidence regarding its clinical validity for number of symptoms and health conditions. In some research studies we can observe inconsistent evidence with some reporting positive effect of yoga interventions, but some are less conclusive. In our review we summarize the current evidence on the clinical effect of yoga intervention on various factors of physical and mental health.
Number of research studies outline plausible effects of yoga interventions on inner health. However, not all studies used adequate or congruent instrument to evaluate the overall effect of yoga intervention on mental health. Even though not all studied apply same tools to evaluate stress, they actually prove that yoga may limit stress level as impressive as other actively regulated interventions like cognitive behavioral therapy, relaxation . When we evaluate the effects of yoga on fatigue in various medical conditions such as sclerosis multiplex, cancer, chronic pancreatitis and asthma we can found overall small but plausible effect . The same effects we can observed in healthy people . Number of studies investigating effects of yoga on anxiety describing beneficial effects when compared with passive and active controls . The study results investigating effects of yoga on depression have revealed mixt results . Indeed, there is an exigence to conduct more research studies with sound methodological platform on larger sample size to determine whether there is substantial justification to consider yoga as a treatment of depression.
Most studies result pointing out to the conclusion that yoga has positive effect on sympathetic and parasympathetic activation and cardiovagal function . We have alleged claims that yoga can positively enhance modification in sympathetic activation of cardiac and vagal function, and also contributes to the autonomous neural system homeostasis primarily by sympathetic to parasympathetic activation . Literature review on the effect of yoga on cardiovascular endurance reporting
significant improvements in overall cardiovascular endurance of young subjects who were given varying periods of yoga training for extended period of time . Studies investigating the effects of yoga on blood pressure and hypertension report a reduction of systolic and diastolic pressure. However, there are several noted potential biases in these studies (i.e., confounding by lifestyle or others) which makes it difficult to detect an effect specific to yoga . Some authors found small, insignificant improvements of systolic and diastolic blood pressure in favor of yoga when compared to no treatment . When we evaluate yoga’s effects on lung function in healthy volunteers and patients with bronchitis and asthma we can conclude that in healthy volunteers practicing yoga, there are reported improvements of selected pulmonary function with inspiration and expiration breathing control techniques, particular body postures and relaxation methods . In another study on patients with asthma we can observe improvements in peak expiratory flow rate, medication use and asthma attack frequency . Systematic reviews examining the effects of yoga on risk indices associated with insulin resistance syndrome reported postintervention improvement in various indices in adults . However, we have to take into consideration that the results varied by population (healthy adults, adults with cardiovascular disease risk, adults with type 2 diabetes, etc.) and study design. Studies evaluating yoga in comparison to medication intervention showing significant subjugation of fasting glucose with type 2 diabetes mellitus. We can conclude that differences in study populations, and interventions can stand out as a possible explanation for the observed heterogeneity of results. When we observe effects of yoga on musculoskeletal function, chronic pain conditions, and pain associated disability (lower back
pain, arthritis) all of these studies reported positive effects with
respect to pain [9,10]. Moreover, studies that included yoga for the
treatment of headache- migraine, hemodialysis, irritable bowel
syndrome, labor pain, etc., All of these studies reported positive
effects in favor of the yoga interventions . Despite some study
limitations, there is evidence that yoga may be useful for several
pain-associated disorders. Thus, well-design large scale studies
are needed to verify these findings.
A growing body of research evidence supports the belief
that certain yoga techniques may improve physical fitness .
While exercise has been shown to definitely improve parameters
of fitness, the fitness effects of yoga have only been examined in
handful of studies [12,13]. Yoga seems to provide many of the
benefits typically associated with exercise . It is possible that
differences in fitness outcomes found in the comparison studies
of yoga and exercise might not have been found if exercise were
compare to the more vigorous forms of yoga. The differences
that have been found between yoga and exercise interventions
may be a result of how the two differ in their effects upon the
hypothalamic -pituitary-adrenal axis and the sympathetic
nervous system . To make distinct differences between yoga
and conventional exercise with the current research has proven
to be difficult. In one study significant increases of strength,
muscle endurance, flexibility, and VO2 max occurred in 10 healthy
volunteers after 8 weeks of biweekly asana and pranayama classes
. In one study , sun salutation practice had led to decrease
in body weight and % body fat and increase in % lean body mass.
Further, practicing yoga for 30 min a day increased MET to 2.5 in
females. But inclusion of “Sun salutation” in the session increased
the MET to 3.74 . When we look on older subject with respect
to physical fitness and functional status, these studies reporting
moderate effect size for gait, postural balance, body flexibility,
body strength, and weight loss . In that context, we should
investigate the most appropriate duration of yoga intervention
and the most suitable postures and yoga styles for the older
cohorts. All above mentioned studies require to employ sound
methodology and thorough statistical analysis that will embrace
(larger and randomized samples with more blinded studies).
These studies need to be replicated in a variety of populations,
both sick and well, as the effects may vary depending upon the
health status of selected sample.
Presented reviews point out a number of distinct areas where
yoga may be beneficial. Research studies on yoga as a therapeutic
intervention in relatively new field of study, therefore studies in
related domains are rather small. We observe high heterogeneity
in (group selection, type, frequency, intensity of intervention,
selected measures, motivation of the participants, health status
etc.). Therefore, better understanding of the significance of yoga
under different circumstances is required. In contemporary
society more and more people are turning to yoga for its mental
benefits in relative to pharmaceutical, clinical intervention.
Number of studies suggest that practicing yoga shows promise for
promoting better population mental health. It appears that deep
slow breathing in combination with movement and other aspects
of yoga haw ability to bring person a greater sense of tranquility.
We have base evidence that yoga can reduce symptoms of anxiety
and depression [18,19]. However, additional investigation in this
field are highly recommended, specifically because of the positive
relevant psycho-physiological rationale. While it is not surprising
that physical training can enhance physical fitness by the means of
yoga or conventional training protocol. However, these effects are
powerful in healthy individuals, still much weaker in individuals
with chronic pain conditions. This facticity deserves further
investigation. Motivation of participant stand out as an important,
crucial factor that need to be emphasize. Compliance with yoga
objectives, taking part in the class of yoga may be higher in social,
community setting in comparison to performing yoga isolated,
alone at home. However, intervention of short duration might
be an option for some specific indications (i.e., pain, depression
symptoms) while the cardiovascular and overall physical fitness
effects might require long term practice.
Obviously, yoga intervention programs demand an active
attendance, and therefore adherence might be a crucial point
that can limits potentially beneficial effects of yoga. It is
comprehensible that lifestyle play crucial role in health outcome.
In that context plausible attribute of yoga intervention is that it
may in fact be assistive for the execution and maintenance of such
lifestyle changes due to the experience of well-being from the
practice, which will in turn support desire to adopt and maintain
healthy behaviors. Thus, further investigation should clarify which
individual may benefit from the intervention and also which facet
of the yoga intervention (i.e., physical activity, meditation, lifestyle
alteration) or which particular yoga style is more effective. Yoga
in its foundation has potential to be implemented as a safe and
plausible treatment that is basically cost effective, enhancing self
-confidence, self-esteem, self-efficacy, and is frequently associated
with additional positive side effects.
The extent to which yoga intervention is curative treatment
remains to be clarify. At the present time it is safe to suggest
that yoga can be a beneficial supportive additive treatment. Yoga
stands out as a low risk for side effects, when selecting appropriate
postures and exercise protocol. However, the meditative, cognitive
aspect of yoga could be questionable for the people with mental
instability or personality disorder. We have not enough relevant
evidence to claim, that yoga practice has negative impact on mental
health. Even though, number of studies claiming positive benefits
of yoga, multiple methodological limitations (heterogeneity of
selected sample, small sample size, motivation of participants)
bound the generalization of these ever-promising studies. We
will need more, cross-sectional and longitudinal studies in order
to determined, verify rather promising outcomes. In addition,
we have to be aware, that yoga is not “exercise” but a “process.
Future research is needed to examine the difference between yoga
as an “exercise” and yoga as a “process”, particularly, how these two modalities may differ in the quest for better health. At the
conclusion, yoga practice need to be further investigated as a tool
to enhance physical fitness and hence quality of life.