mentally it changed me in many ways but one that really sticks out is this.
getting into the gym changed whole mindset and perspective on life. going into the gym everyday and busting improving my speed and strength, and condition where i never imagined. while watching someone who comes into the gym once a week, walk on the treadmill and doesn't try to challenge themselves. this showed me there are people who are motivated and believe sky is the limit and, on the other hand, people who are satisfied with being mediocre and live with a ceiling over there head.
i'm not even 30, and quit my job in november to work for myself. i daytrade full-time and alot of my inspiration is because of what i went through in the gym. i believe training/working out in the gym is more mental than it is physically, especially cardio.