As far as personal experience, I find breathing exercises should be slow and deep, generally with breath retention that is extended over time, as opposed to just deep breathing in and out at a 'regular' speed. Traditional yoga usually emphasizes this (as opposed to the new-age westernized yoga). I think many people who find no results just breathe deep but dont slow it down. You should feel like your breath has been 'stretched' by the time you're done. Id also find a good teacher if you're serious because you can definitely overdo it/do it wrong.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3681046/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4728953/
As far as personal experience, I find breathing exercises should be slow and deep, generally with breath retention that is extended over time, as opposed to just deep breathing in and out at a 'regular' speed. Traditional yoga usually emphasizes this (as opposed to the new-age westernized yoga). I think many people who find no results just breathe deep but dont slow it down. You should feel like your breath has been 'stretched' by the time you're done. Id also find a good teacher if you're serious because you can definitely overdo it/do it wrong.