Premature Ventricular Contractions & Exercise

I'm a 37 year-old male and have been an avid exerciser for some 14 years. For the last 6 years or so, I have been going to the gym on average 5 to 6 days per week. On all of those days I do 35 minutes of cardiovascular work (elliptical machine) that keeps my rate heart at about 147 bpm. On 3 of those days I also do some fairly heavy weight training. I attempt to eat well, although it's tough to keep away from chocolate! I have never smoked, I drink de-caff drinks, and have maybe 4 beers on a given Friday night (no other alcohol). I don't use any strenght "enhancers" nor do I take any medication. And yet I've recently been to the doctor who diagnosed my irregular heart beat as premature ventricular contractions or PVCs. That really bothered me, given my continued attemtps to be and remain in good shape. I feel fantastic otherwise, no fainting spells, no shortness of breath, no lightheadedness. So why the PVCs? Mine occur anywhere from every 4th beat to every 30th beat or more. Sometimes not at all, but they're generally there. Thankfully, I have never felt them during my workout, only when I'm at rest (watching TV or reading in bed). My questions:

1. Do I have cause for concern?
2. Can I continue to work out at my current pace (cardio + weight training)?
3. Do I need to do anything differently?

My doctor didn't seem too concerned and I understand from my family that my Mom suffers from PVCs and palpitations from time to time, and that my dad and 1 sister both have heart murmurs (the doc says I don't have any murmurs).

Thank you in advance for any help/advice!

You are welcome

Servant to the humblest person in the universe,

Some folks have hearts that are sensitive to alcohol (even moderate amounts).

Someone will need to examine you and review your entire history in order to advise you well on whether you can exercise safely.

You are welcome, Jim.

Servant to the humblest person in the universe,

Thank you all for the replies, they've been very helpful!