I spend 40-50 hours a week at work, and another ten hours commuting between three offices. I put my training on my schedule and tell people if they try to schedule me for a meeting when it says NOT IN THE GODDAMN OFFICE, that I won't show up. So I make it to training. I go three on, two off at the gym. "I work too much" is not an excuse. Gym time is quite frankly more important to me than office time, and while I'm not super overt about that, I make it clear that I'm not fucking around when I say "I gotta leave."
If people can say "I gotta go pick up my kids," well, fuck them, I didn't have kids because I know how to not have goddamn kids and I have every right to leave to train if those silly cunts have the right to leave to pick up their kids.
Make it a priority.