What is Reddit's opinion of Manual of Freediving: Underwater on a Single Breath?

From 3.5 billion Reddit comments

You've found some good spots. Find a zero-swell day and go out snorkeling. Lovers' is going to have better snorkeling close to shore than Breakwater.

Van Damme is good too, but the visibility is normally worse than it will be in Monterey, and there's less stuff to see.

If there is a single book, it's probably the Manual of Freediving, but don't let reading be a substitute for actual instruction.

Reach out to the Monterey Bay Tritons if you're thinking about spearfishing. There's also a Facebook page called something like "Monterey Freedivers" that's pretty active and has a few local instructors.

So the Blaine thing - yeah they hyperventilate. He also breathed pure 02 for his record attempt. For me it is a gimmick - but that is just my opinion.

Dangers of build up of C02 - yeah it can't be good for you I suppose. It raises your blood pH and such - I'm not a medical pro or anything. Maybe check out the deeperblue forums for more info: https://forums.deeperblue.com/threads/long-term-effect-of-repetitive-apnea.16190/

Tips for training safely: read and learn a lot. There is so much good information out there online, this subreddit, the deeperblue forums, books written by pro freedivers like this one: https://www.amazon.com/Manual-Freediving-Underwater-Single-Breath/dp/1928649270 (it's a bit old now but still has a lot of sane info). Then when you are ready to apply your knowledge have someone with you.