When I find myself in a mental dead end--there's something to figure out but I'm too stressed out intellectually to think of solutions (I work at home as a web content writer and blogger)--I go out of the house and take a brisk walk break. It rejuvenates your body systems, especially circulation, and helps make you think actively again.
While walking, don't think of the problem first. Enjoy your surroundings and appreciate what you see. Then, slowly, as you continue your brisk walk, go back to the problem. You'd see that you'd get a new perspective, a new way of seeing it. And then ideas come. In fact they sometimes cascade.
When I get fed up with workout programs and schedules, I go out and just walk. Well, sometimes I just stand up and do squats, especially when it's raining. But sometimes I walk. As experts advice, walk for some 45 minutes to an hour at least 3 times a week--or else 30 minutes every other day. I add push-ups and shadow boxing to that.
When walking has renewed my determination to workout, then I jog again and do my usual workouts. Walking is a therapy and an opportunity for mediation. So never underestimate it. Do it often. Running can make you sweat more, but it seldom affords soul therapy and meditation. That's why walking can also be a character and attitude workout.
So sometimes, plan on relaxing and just walk.