Start slowly by doing short workouts: Take a 10 minute brisk walk and do a set of push-ups. Keep expanding the duration of your workouts and make them more challenging over time. Add some hills to your walk or pick up the pace. Even 10 minutes of exercise has benefits.

Exercise becomes harder to do when we tell ourselves we have to work out for 30 minutes or an hour. Do what you can, when you can, with what you have. :-)