Interesting study came up this week. Following a 3-month yoga retreat, increases were observed in brain-derived neurotrophic factor (BDNF), reductions in awakening cortisol, and reductions in some (not all - interestingly) inflammatory markers.
In plain language, this means the participants: grew more neurons; reduced stress; and improved health and resilience. You might think 'duh'. I think 'great'. We are moving beyond simplistic measurement of the effects of this practice. It's challenging because science demands a reductionist approach to tease out an active component. However, yoga is a system for good reason. It includes the philosophical, the physical, the breath, relaxation, mindfulness and meditation because a complete and complex approach is needed to match the complexity of an individual.
Now these were predominantly experienced yoga practitioners who already had a daily Hatha practice and stable sitting (meditation) practice. This suggests they were coming off a low base and already adept at the practices. They were also on vegetarian diets during the retreat which contributes to these results.
However, they also demonstrated significant changes in psychometric measures of anxiety, depression, and mindfulness - and they were already practitioners.
Check it out if you're interested. If you can't access the study from the link below, let me know.