“I don’t have time” is the oldest excuse in the book.
Since time is a man-made construct, and we decide what is worth time, and where we spend time, it would seem to me that “I don’t have time” is just another way of saying “I’m not that interested” and “I don’t think this is more valuable than what I’m currently doing.”
When you say “I don’t have time” look over everything you’re doing and determine if that’s really true. This is especially true if your excuse for not going to the gym is that you “don’t have time.”
When you are trying to get someone to do something and they say “I don’t have time,” take a moment to determine where you missed the opportunity to adequately demonstrate the value of your request.
All of this should help make time easier to find.