Muscles: how do you get JACKED!?

The science of muscles, motivation and steroids is fascinating. In recent years it seems humans have become obsessed with health and fitness, but what does science say? Also, is 'roid rage' real? We break it all down today! STUDYTIME: MUSCLES 02:53 WDWLTW: 28:35 - puppy dog eyes have evolved to manipulate you! 31:25 - how much garbage is in space?