For many years, this was a subject which was usually answered with personal opinion. There was no real proof whether it was more effective to perform cardiovascular activity before or after a workout, so most people would simply do what worked for their own body and pass on their findings to others.
That’s no longer the case. Today we’ll be looking at a few recent studies and talking about why science has now shown cardiovascular activity to be more effective when performed before resistance exercises, as opposed to afterwards. 
While both approaches ultimately yield positive results, a study at the James Maddison University discovered that an aerobic-weights routine yielded far more lean muscle growth than a weights-aerobic routine.
For those who are training for fat loss, the findings were also highly in favor of doing aerobic exercise prior to any barbell work. The Journal Of Strength And Conditioning discovered that weight loss, specifically fat loss, was increased greatly in individuals who did their aerobic exercise first.
Of course, it is highly important to remember that if you are regularly training with weights and getting a good deal of cardiovascular activity into your life then you will still see positive results no matter which order you perform them in….
The main findings of recent studies focus on the effects of two enzymes:
* Mammalian Target Of Rapamycin (also called mTOR for short!)
While mTOR is the enzyme responsible for kick-starting the body into the muscle building process at the end of a tough resistance workout, AMPK gets released during aerobic activity to adjust the body for endurance. For around 60 minutes after a workout you’ll have a surge of mTOR, meaning the golden window for nutrition is this period if your goal is to gain lean muscle and burn excess fat. This surge lasts around 6 hours. 
If you finish your weight training and then sit on a bike for 45 minutes you have not only wasted the bulk of your golden nutrition window, you have also made a fatal mistake. When the body releases AMPK, i.e. during cardiovascular exercise, this hormone doesn’t co-exist with mTOR and actually kills it off.
Although you can certainly achieve a fitter physique regardless of whether you do cardio before or after weights, recent studies seem to weight heavily in favor of performing your aerobic activity before you begin using dumbbells and barbells. In order to learn how to lose weight, getting past common myths like this is part of the battle. You’ve just done that today and can now apply this new knowledge to your own training.