The mind-body connection through yoga and mindfulness helps those who are unable to stay mentally focused during practice (even if they are physically performing their poses properly). The reason for being unable to concentrate is usually breathing. Slower breathing in yoga directly influences the autonomic nervous system, which moves the body from stress mode (sympathetic nervous system) to rest and digest mode (parasympathetic nervous system). 

Check out here to know more - https://evolationyoga.com/blog/2026/3/27/the-science-behind-slower-breathing-in-yoga-and-mindfulness