How Much Exercise?

I have read many articles on how many times a week we should exercise. Most say at least three times a week for 30 minutes at a time. I believe our chemical make-up and muscle structure varies from person to person. I can't say that the three times a week routine is good or bad. What I do suggest is to start with the three days a week and work your way up slowly. Don't weigh yourself but instead determine on how tight your muscles feel each week. Do your muscles feel like they are growing or do they pretty much feel the same? If they feel the same you need to add a more intense workout. Remember, you constantly need to trick your body otherwise you will become stale to the same old routine. The key is to listen to your body and always challenge yourself and you will always see improvements.