Guilt is a terrible long-term motivator. For me, two big mental shifts made an enormous difference. 1. I had to stop feeling like someone else was going to tel

Guilt is a terrible long-term motivator. For me, two big mental shifts made an enormous difference. 1. I had to stop feeling like someone else was going to tell me how to do it or make me do it. Start going to the gym and do whatever exercises you like doing. Keep showing up, and change your posture. Don't think "I should exercise more." Think "I'll go on Tuesday nights when I don't have as much going on." Work from the assumption that you're already a person who exercises, and just think about the mechanics of actually making time for it. We spend way too much time thinking about how we become gym people instead of just going and exercising. 2. As some other people have pointed out, realize that you can't undo a sedentary work day by working out for an hour at the end of the day. One trick I use is to do pomodoros (25 minute chunks of work) followed by a 3-5 minute break where I get up and just walk or look out the window. If my motivation or focus is flagging, sometimes I'll use that time to read a couple of paragraphs on my Kindle app. (Churchill said "a change is as good as a rest"; sometimes taking your eye of the ball for a minute can help you refocus your mind). By moving a little many times throughout the day, I find I don't build up those slow and steady tensions that ruin your body and will to exercise.