The terms "circuit training" and "interval training" are often used interchangeably, but they are not the same workouts. The two workout types use different exercises, offer different benefits and garner different results. Both are effective, time-efficient workouts that you can easily add into your weekly routine to boost your cardiovascular and musculoskeletal fitness.
Circuit training is primarily a resistance-training workout. Traditionally, it includes rotating through nine to 12 exercises, or stations, performed for 15 to 45 seconds each with little to no rest in between. Aerobic exercise such as jumping rope or jumping jacks is often featured in circuit training in amounts between 30 seconds and three minutes, either in between each resistance exercise or at the end of each round.
In contrast, interval training is a cardio workout. You choose your aerobic exercise -- swimming, running, cycling or rowing, for example, and perform intervals of high-intensity effort alternated with periods of recovery. For example, during a jog, you would break into a one-minute sprint, then return to your jog for one to two minutes to recover. You would repeat the intervals for the duration of your workout.
Circuit training benefits focus on the musculoskeletal system and body composition. Resistance training builds lean muscle mass and strengthens bones. Building lean muscle mass often leads to a reduction in fat mass. Circuit training may also slightly improve cardiovascular fitness as a result of reduced fat mass.
Interval training primarily improves cardiorespiratory function. The heart is intermittently overloaded during interval training in a way that steady-state training can't achieve. As the muscles adapt and become stronger during resistance training, the lungs and heart adapt to handle the increasing load of high-intensity exercise. Improved heart function allows more efficient delivery of blood to working muscles, increasing their ability to work harder for longer periods of time.
Interval training may be more effective at burning fat, especially abdominal fat than steady state cardio exercise, according to a review of research in Journal of Obesity in 2011. It may also accomplish the same results as steady state exercise in less time.
Sample Circuit Training Workout
Circuits can be comprised of lower body and core exercises, upper body and core exercises or total body exercises. A total-body circuit might include the following exercises:
- Chest press with dumbells
- Leg press
- Dumbell row
- Walking lunges
- Shoulder press
- Lat pulldown
- Biceps curl
- Triceps extension
- Calf raise
- Bicycle crunches
Perform each exercise for 45 seconds with little to no rest in between exercises. Repeat the round two or three times.
Sample Interval Workout
There are many variations of interval workouts, but the basic structure is the same -- all-out effort followed by recovery in a 1:1 to 1:4 ratio. A simple but effective treadmill interval workout looks like this:
- Warm up for 5 to 10 minutes at a brisk walking or jogging pace.
- Increase your speed to a sprint for 60 seconds.
- Return to a walk or jog for 2 minutes.
- Repeat for 5 rounds.
- Cool down at walking or jogging pace for 5 to 10 minutes.
You can also do sprint intervals on a track or on a jogging trail. After a warm up, sprint for 30 to 60 seconds, walk or jog for 2 minutes and repeat.
Another variation on intervals is a countdown workout:
- Warm up with a jump rope at an easy pace.
- Perform as many jump rope revolutions as you can in 2 minutes.
- Rest for 2 minutes.
- Perform as many revolutions as you can in 1.5 minutes.
- Rest for 1.5 minutes.
- Complete as many revolutions as you can in 1 minute.
- Rest for 1 minute.
- Complete as many revolutions as you can in 30 seconds.
- Rest for 3 minutes.
- Repeat the countdown one to two times.