This is pranayama set builds slow, medium to fast cycles of breath.

If you follow this link there's a big study on this kriya:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3573542/

"Sudarshan Kriya has been found to be effective in alleviating the symptoms of mental health issues like post traumatic stress disorder, anxiety, depression, trauma and bipolar disorder, and physical health issues like high cholesterol, high blood pressure, and issues related to the endocrine system and immunity."