Circuit training combines some of the best aspects of resistance workouts and cardiovascular exercise. It allows you to build strength while simultaneously maintaining an elevated heart rate for the extended periods that are best for calorie burn and heart health. A 45-minute circuit session is intense, but once you work your way through a full routine, you'll be quite fit.
A circuit workout consists of a series of stations. During the workout, you spend a set amount of time at different exercises, with a brief rests between each. What exercises comprise the workout will depend on your goals and available equipment. If you favor strength training, you can set stations for weightlifting and body weight exercises. If you prefer a cardio workout, you can make them out of calisthenics, treadmill runs and aerobics routines.
Two minutes on each exercise, with a minute between, is a common way to organize a circuit training workout. For 45 minutes of work, this means setting up 15 different exercises. If you prefer to keep it simple, you can set up smaller circuits to go through multiple times. Three trips through five stations would work, as would two trips through seven stations with a final full-body exercise.
Because you are moving between different exercises, you can maintain concerted effort longer with a circuit workout than with routines that keep up just a single kind of motion. According to health resource website HealthStatus, a 160-pound person will burn about 330 calories in a 45-minute circuit training session. Heavier people will burn more, and lighter people will burn less.
Oregon based fitness coach Ben Cohn advises that organization is the key to a successful circuit workout. If you don't know what you'll do next, or you have to find or set up the equipment for your next station, your rest periods will grow too long and you'll minimize your benefit from the routine. Cohn also recommends keeping time with a magnetic kitchen timer. These are easily portable from station to station, and you can stick it to most of the gear you'll find in a gym.