[Epsilon]

Thanks for all the answers. I should've tried searching before beginning a new post.

I've also heard that arrythmia isn't that uncommon. My wife, who doesn't freedive, had them almost daily for few months last spring. The issue was examined, and nothing serious was found. It probably was a stress related problem.

As I wrote in my previous post, I haven't had any problems for months now. I will try to continue with less hard training, and if I get arrythmia again, I'll go and get myself examined. And I'm sure I have to pay more attention to what I eat and drink, especially before training.