Many studies have shown that people doing strictly weight training have significantly more strength and size gains than people who do both cardio and weights. Basically you start using your muscle to fuel your cardio workout. That might be something you want to consider depending on what kind of training you are doing, what your goals are and how much time you have.
"I believe that banking institutions are more dangerous to our liberties than standing armies. If the American people ever allow private banks to control the issue of their currency, first by inflation, then by deflation, the banks and corporations that will grow up around the banks will deprive the people of all property until their children wake-up homeless on the continent their fathers conquered."
-Thomas Jefferson 1802