The feeling after hitting a good workout is one of the best feelings in the world. Not only are you proud of yourself for going for it and getting it done, but your body just feels… right. Your stress levels have been managed, the hardest part of the day is over, and perhaps you get to reward yourself with some good food. There’s nothing like it. It’s a feeling that scientists could spend their whole lives trying to bottle, but it would never be the same. 

Understanding this feeling is key to understanding the gym rat. Gym rats aren’t quite addicted to the pain, they’re addicted to the feeling after the pain is over. You know this if you’ve ever been in the middle of a workout and thought «I’m never going to do this again.» And then once it’s over and you’re toweling off, the rush is so pleasant that you get up and do it again the next day.