body building

Body building is anaerobic exercise because last few seconds during exercise and between sets must rest but duration of rest depend on target.  fitness is aerobics. 
To benefit your health you need both anaerobic and aerobic . to shape,cut and tone your  body you need the anaerobic and  to work on your cardio vascular and burn calories  you need aerobic but also building muscles can burn more calories.

fitness

Aerobic exercise does require oxygen for energy. This is observed during exercise that is less intense but of longer duration. This energy system is primarily used during events lasting longer than several minutes, such as a two-mile run or the Tour de France bicycle race. The potential does exist that one can use both systems, as in soccer, where a match requires ninety minutes of continual activity with short intense bursts of effort.