To answer your question Yes you can throw cardio in the bushes. Should you? fukk no. In the grand scheme cardio is the most important. This will be a lengthy post because I want to explain why. Cardio is for the cardiovascular system obviously so its to strengthen your heart not to burn fat or weight loss. Your heart is your life pump that moves your blood which carries your oxygen and 99% of all the nutrients to your body. You can lift weights and get stronger with out cardio and you can still burn some fat. BUT you wont be able to life with intensity and to full potential for very long. You wont be able to do Aerobic or Anaerobic exercise ( which are for losing) very efficiently because of your lack of endurance and stamina. What ever growth in strength you achieve without cardio will increase byat least 60% because your heart is strong enough to deliver the blood. The more mass you build the more your heart has to pump. The stronger your heart, the better you can lift, the faster youll get results, the harder your erections will be as well. Strengthening your heart is good for your sex life. Ultimately you need cardio. As someone else said Interval cardio is best. Example. if you like the treadmill, fine do it jog 400 meters/ 1 lap. Stretch. get back on jog 200 meters then sprint as fast as you can for 100 meters, slow down to a walk for 100 meters, then sprint again for 100 meters, slow down to a walk for 150 meters, increase the incline to 3 out of 10 jog for 200 meters, sprint it out 100 meters, walk it out