.02
"More isn´t always better....go for intensity, not volume."
I agree with this one here......when working out, it's not "How long" you stay in the gym, but what you get accomplished in a set period of time. when on your cardio days:
"The most effective type of cardiovascular exercise is known as "High Intensity Interval Training" (HIIT). This involves a combination of aerobic exercise, and higher intensity "wind sprints." There are several variations of HIIT, but all involve alternating between moderate and high intensity for intervals anywhere between 30 seconds and 5 minutes each. Start by warming up for 2-3 minutes. Following your warmup, you move to a moderate level of intensity. The majority of your energy here is coming from aerobic metabolism (burning glycogen and fat using oxygen). Try to recruit as much muscle activity as possible from your arms, legs, back and buttocks. After your wind sprint, you drop back down to a moderate level of intensity and do it again