Christina Rosso from Yoga Alignment here discussing our findings:

Flexibility, relaxation and balance. These are some of the most common reasons why many start practicing yoga, but did you know that there are even more proven benefits of yoga that go deeper than these well-known benefits?

I have been practicing yoga for over 12 years and have taught over 1000 hours of classes in the last 5 years. I started practicing yoga to help with my mental health during a tough time in my life, as well as wanting to increase my overall fitness levels. My private students, comprised of business professionals, professional athletes, medical doctors, physical therapists and chiropractors, have all started practicing yoga for different reasons. Some wanted to become more flexible and use yoga as a tool for stretching, others wanted to practice as an aerobic workout and build strength. Some wanted help with back pain, others wanted help with relaxation and stress reduction.

What myself and my students didn’t really realize when first starting to practice yoga is that, in doing so, we would receive even more benefits than we thought!

There have been many studies on the therapeutic effects of yoga with much more research to be done. We looked at various studies, systematic reviews and meta-analyses to find out what benefits have been studied proven. Many of them involved 6-12 week yoga programs. We found that there were many proven mental, physical and physiological benefits, so we thought we would share them with you! Here is what we found:

MENTAL HEALTH BENEFITS:

1. Yoga Helps Decrease Symptoms of Anxiety and Depression
“Meta-analyses of RCTs have reported that yoga is associated with large reductions in depression and anxiety in cancer patients and has a significant impact on depression (and pain) associated with fibromyalgia” [1]

From our research, further studies need to be done on the long-term effects of yoga for depression and anxiety.

2. Yoga Improves Brain Function and Working Memory
A systematic review of 11 studies examining the effects of yoga practice on the brain structures, function and cerebral blood flow showed that “yoga practice can affect the anatomy of the brain. Yoga practice appears to be linked to anatomical changes in the frontal cortex, hippocampus, anterior cingulate cortex and insula.” [2]

“Studies investigating changes in the functional connectivity of the brain following yoga practice have primarily identified increases in the default mode network, one of which found that those changes were related to memory performance.” [2]

“Exercise alone and mindfulness alone, as well as a combination of the two in the form of yoga practice, have a positive effect on this critical brain structure implicated in age-related neurodegenerative diseases and chronic stress… yoga may hold promise to mitigate age-related and neurodegenerative declines” [2]

3. Yoga Reduces Stress
In a study of 60 mental health professionals working in a teaching hospital, it showed that those that enrolled in a weekly 60-minute yoga program for 12 weeks “experienced a reduction in work-related stress and an increase in autonomic nerve activity” [3] and an increase in adaption to stress.

PHYSICAL HEALTH BENEFITS:

4. Yoga Relieves Back Pain, Improves Spinal Function and Reduces Use of Pain-Relieving Medication
In a study of 80 females, a “7 day residential intensive yoga-based lifestyle program reduced pain-related disability and improved spinal flexibility in patients with CLBP [chronic low back pain] better than a physical exercise regimen” [4]

In another study, it was “demonstrated that a 16-week yoga therapy intervention caused a significant reduction in self-reported disability and pain, and reduced use of pain medication.” [5]

5. Yoga Improves Flexibility
In a study involving 56 women between the ages of 50-79, “results indicated that practicing yoga postures (asanas) even once a week led to an increase in the mobility of spinal joints and flexibility of the hamstring muscles. All practitioners showed some improvement in flexibility regardless of age.” [6]

6. Yoga Increases Levels of Strength, Balance and Mobility
In a study with 118 males attending 8-week (three times a week for 1 hour) yoga program, “we observed significant time effects for each of the balance, flexibility, strength, and mobility measures, indicating that both groups improved and Hatha yoga was just as effective as the conventional CDC strengthening guidelines in improving these functional fitness outcomes in community-dwelling older adults.” [7]

A meta-analysis indicated that “Yoga interventions resulted in small improvements in balance and medium improvements in physical mobility in people aged 60+ years.” [8]

7. Yoga Improves Proper Habitual Body Posture and Spinal Curvature
A study of people over 55 showed that practicing yoga once a week for 8 months along with additional exercises including basic positions of hatha yoga in home conditions 1-2 times a week for about 30 minutes showed “that yoga training leads to an improvement in the habitual body posture in case of aggravating (excessive) anteroposterior curvatures of the spine” [9]

Another study of participants doing 90 minutes of Hatha yoga classes once a week over a period of 15 weeks finds that “hatha yoga exercises have a positive impact on one's body posture in the sagittal plane.” [10]

OTHER PHYSIOLOGICAL BENEFITS:

8. Yoga Helps to Prevent Heart Disease
A meta-analysis showed “serum level of triglyceride and high density lipoprotein cholesterol (HDL-C), blood pressure and body mass index were significantly improved…. it is associated with improved quality of life, less number of composite cardiovascular events, and improved cardiovascular risk factors.” [11]

Something to note is that this specific study showed that yoga had no effect on low density lipoprotein cholesterol (LDL-C) or total cholesterol. [11]

Another meta-analysis discussed that “yoga therapy has shown to be significant in the reduction of systolic and diastolic pressure in prehypertensive population… and can be beneficial in reducing the chances of developing hypertension or cardiovascular diseases” [12]

9. Yoga Improves Respiratory Function
A study where participants had been practicing yoga for 90 minutes, 6 times per week for six weeks indicates that yoga “improves respiratory muscle strength and endurance… This can be attributed to a combination of deep breathing and yoga postures. In earlier studies also, we have found that yoga training of longer duration improves respiratory pressures” [13]

10. Yoga Improves Indicators for Good Health
42 studies were included in the meta-analysis. “Interventions that included yoga asanas were associated with reduced evening cortisol, waking cortisol, ambulatory systolic blood pressure, resting heart rate, high frequency heart rate variability, fasting blood glucose, cholesterol and low density lipoprotein, compared to active control.” [14]

Another study showed that “yoga had a significant and direct influence on a cortisol response that correlated with yoga's antidepressant effects,”[15] lowering cortisol levels in participants.

11. Yoga Reduces Inflammation
In a study, 48 male study participants, aged 30-58 years practiced yoga for 45 min, six days a week, for 12 weeks, excluding weekly holidays. “The results confirmed that the yoga group had significantly lower level of IL-1 β and increase in IL-10.” [16] These results indicate a reduction in inflammation by reducing pro-inflammatory cytokines and increasing anti-inflammatory cytokines.

12. Yoga Improves Sleep
In a study including 12 weeks of yoga classes, held twice per week, incorporating yoga postures, meditative yoga, and daily home practice of meditative yoga “showed significant improvements in a range of subjective factors, including overall sleep quality; sleep efficiency; sleep latency and duration; self-assessed sleep quality; fatigue; general well-being; depression; anxiety; stress; tension; anger; vitality; and function in physical, emotional, and social roles.” [17]

I bet you're thinking that any exercise program can help do the same.
Let’s take a look:

A comprehensive review found many studies that compared the benefits of yoga to exercise programs like stationary cycling, walking, jogging, stretching, aerobics, running and more. “Overall, the studies comparing the effects of yoga and exercise seem to indicate that, in both healthy and diseased populations, yoga may be as effective or better than exercise at improving a variety of health-related outcome measures including HRV [Heart Rate Variability], blood glucose [blood sugar], blood lipids, salivary cortisol, and oxidative stress. Furthermore, yoga appears to improve subjective measures of fatigue, pain, and sleep in healthy and ill populations.” [20]

My suggestion is to compliment any exercise program with yoga and vice versa for optimal benefits!