It's relative to the person. As heavy as *you* can for the given rep range.

So if you're lifting in a range of 8-12 reps, but can actually do 22 reps, your weight is way too light. Once you can consistently go beyond the rep range that you're in, up your weights.

That's what makes strength training top dog when it comes to changing your body composition. If your body adapts to a certain amount of steady state cardio (say 30 minutes/day) then you'd have to do more cardio (say 45-60 min) to now get the same result. This is why we'll see people end up doing hours of cardio, and still at a standstill. With weights, you can do the same rep range, but keep upping the weights, whenever your body adapts. Therefore constantly forcing the body to change.

So "lift heavy" (for *you*) :flowerforyou:

Kiki