Don't fall into the either/or trap. I know too many people who have succumbed to faulty thinking about exercise. Someone decides to walk one hour each day. When he can't reach that target, he quits outright. "If I can't even walk a measly mile," he thinks, "what's the point?" The point is that you can still walk. You can still get outside. You can still move the body God gave you. A one hour walk is a completely arbitrary number. Don't let a number define you. As long as you're moving forward, you're still exercising.
Be a perseverer, not a quitter.