Want to hold my breath longer

[behindThePeak]

a ~1 minute breath limit is my weak link when the surf gets big and i want to spend the summer fixing that. I know all about the mental aspect of relaxing while getting rag-dolled. I'm more focused on what exercises or training I can do in the offseason to expand this physical limitation to a reliable 2 or 3 minutes minimum. success stories anyone? Can anyone recommend training programs, resources, tips ect? Ive found a few webpages, but i'm looking for something tried and true in a surfing context...