Lifting Question....

kdiamond

It's not about bulking up or not, forget about that.
It is nearly IMPOSSIBLE for someone to ADD muscle while in a calorie deficit. What you are trying to do is strengthen your existing muscle fibers and protect the muscle you DO have from being destroyed by eating too little.
Furthermore, women have an EXTREMELY hard time "bulking up" without steroids. You will not look like a bodybuilder no matter how heavy you go.

That being said:
"Heavy" is the amount of weight that you can do 10-12 reps with, knowing that you probably could NOT do the 13th. That 12th should be a real struggle. This could be any weight, it varies person to person and exercise to exercise.
I would suggest not wasting your money on 3 lb or 5 lb dumbells as they are useless. I am 5'2" 107 lbs and I use anywhere from 10 to 30 for handhelds depending on the exercise.

WOW...What exercise do you lift at 30???

AGREED!!!

I'm 5'4" 108 pounds.

I deadlift 115 - only 5 reps mind you, but it is HARD.

I think lifting heavy is when it is hard to do 5-8 reps. If you can do 15 reps of something and you're not busting to get the last rep up, you're not working hard enough.

I also work up to it. Using deadlift as an example again, I always warm up with just the olympic bar (45 pounds). I do about 10 to get my blood flowing. Then I add 25 lbs to each side, then 10's, then 5's. I do 5 sets of 5.