Follow The Heart

I am brand new to triathlon (used to run 5ks and a Du) and I am trying develope a SAFE plan to ease back into it without becoming a fatality. I am definitely out of shape (and although I hate to admit it, getting older), so I think my primary factor must be heartrate. My plan is to follow an increasing schedule of distances; follow and respect the heartrate; and let all other variables be what they will. The three big questions are 1) what is a good safe starting average heartrate? 2) what is a good training heartrate for endurance? (3) how quickly can (should) I advance to that training heartrate? So far, I am thinking 1) 110 BPM starting, 2) 150 BPM optimal, and 3) three months gradually (which doesn't mean I'll be moving fast or long distances in three months, just that my training heartrate will be higher).

Comments? Reccomendations?

Slow, gradual progress (and alive) ALWAYS BEATS brief high-performance (and dead).