Whether you have five minutes or an hour to spare, use the Sworkit circuit training app to break a heart-pumping sweat. Grab a bottle of water and leave the excuses at the door.
The free Sworkit app is the personal trainer in your pocket. Simply choose the kind of strength training you want to get in -- full body, upper body, core, lower body or "anything goes" -- and the app goes to work. Well, actually, you do.
The app tells you what to do and keeps time. Bang out each exercise for about 30 seconds and you'll move on to something new targeting whatever body part you're working on. When you're done select a yoga or stretching sequence to reward yourself for all the hard work.