A common question we are faced with here atfitFLEX is the following, should I do cardio before or after my
lightweight bodybuilding, and for how long?
In general, we would need to know your specific goals to give you a precise answer; since we don't, we'll assume they're similar to those of most women: getting fitter and leaner, building some muscle and increasing your strength and endurance. I'll also assume that you aren't hoping to become an elite athlete in either an endurance or strength sport nor looking for extreme changes in appearance. I'll guess, too, that you're asking this question because you're after maximal fat control; in other words, would it make a difference to do aerobics before bodybuilding or vice versa in your quest to get as lean as possible?
If this is indeed your situation, the 1998 American College of Sports Medicine's annual conference presented research from Truman State University in Kirksville, Missouri, that has your name written all over it. Researchers recruited nine men and seven women for their study, all of whom were fairly well trained. One group did a 20-minute treadmill workout at 60%-70% of their maximal oxygen uptake (VO2 max) while the other followed the same aerobic training protocol but after lifting weights. The latter consisted of a six-exercise circuit with weights the subjects could handle for 10-12 reps maximally and going to failure on each station.
After reviewing the data, the researchers found that the group that pumped iron first had higher heart rates and lower respiratory exchange ratios - a complicated method that allows exercise physiologists to determine whether the fuel for exercise primarily comes from carbs or fat. The lower the respiratory exchange ratio, the more fat is used to fuel activity. With higher heart rates and lower respiratory exchange ratios, those study subjects who pumped iron before they did aerobics used more body fat as fuel than the other group.
In the long term, then, you might reap greater benefits from lifting before you do cardio. You may consider dropping the - weights to 60-90 minutes per session and adding about 30 minutes of aerobics. To keep things interesting, vary your intensity between type of exercise and training days. But here we need to address your goals again. Keep in mind that in many respects, aerobics and lifting are polar opposites. If you lift with high intensity and engage in intense endurance training as well, your strength, power and size will more than likely be compromised. Also realize that you can't attain maximal development in either aerobic or anaerobic abilities if you train both with high intensity. As you can see, your goals will strongly influence how you should train.