Is taking magnesium regularly dangerous? I read about the benefits of magnesium for anxiety and general health, and I've been taking about 200mg every other day for a month. I'm a little unsure about what's good practice for electrolyte supplements, and have concerns about its effects - given that I'm already sinus arrythmia/bradycardia on rest (~55-60 bpm). Am I taking too much? not enough? how do I know what is the right dose for me, and when to maybe stop taking it? 

Hx: I had some issues with emotional trauma, a nervous breakdown and alcohol at the beginning of the year. It was a long period of anxiety attacks, chronic GI issues, near-syncope, but I'm over that now. I've also always had inflammation flare-ups all my life. My ECGs/bloods are normal - though I know electrolytes can't always be accurately read by a blood panel.

M, 26, healthy veg. diet, well-hydrated, exercise at least an hour daily.