We are all busy and sometimes it's difficult to set aside 30 minutes each day for exercise. Why not break it into 3-10 minute sessions?
Exercising in short bursts throughout the day- exercise snacking- is a great way to fit working out into your schedule. It's just as effective as doing a continuous workout. In fact, some studies show that it is actually better at boosting your mood, reducing cravings, and sharpening your mental focus than longer workouts.
Pick 2-3 body movements that target different muscle groups. I would suggest air squats, push-ups (a lot of modifications available), marching or jumping jacks. These will not only get your heart rate up, they will also develop functional strength.
Commit to it. Each day when you are starting to fade, lose focus, feel like grabbing a less than healthy snack, try substituting an exercise snack. I'm pretty sure you will find that you feel better in the long run.
So, let's get snacking!