Short burst workouts require an entirely different mentality than long duration workouts. They also have different effects on your body. Depending on why you're working out, one style is going to be better than another, as long as you can handle the stress of the workout.
More and more, researchers are learning the benefits of interval training. Steady cardio was studied for decades before interval training gained the spotlight. It's now proving to be more useful for losing fat and getting fit than steady state.
Steady State Cardio
Steady state cardio is when you work out at the same intensity for a long time. Sixty minutes is a reasonable amount of time to work out without taking any breaks. The only way to sustain this amount of exercise is to do it at a low intensity.
When you do steady state, you're never pushing yourself to the brink. You're working your aerobic energy system, which uses oxygen to power your muscles. You can go for a while on your aerobic energy system. All you have to do is keep replenishing oxygen.
This style of exercise helps lower your blood pressure and trains your heart to pump blood more efficiently. It can help decrease levels of LDL, or "bad," cholesterol levels and fight obesity and diabetes. For overall health, its one of the best types of exercise. Steady state cardio, done often enough, has even been shown to lower your risk of premature death by natural causes.
Interval training is an entirely different beast. You do short and quick bursts, ranging from 10 seconds to two or three minutes long, then rest. You can change around the rest periods based on how intense you want the workout to be.
The most common ratio of work to rest is 1:1. That means if you sprint for 30 seconds you'll rest for 30 seconds. Unlike in steady state exercise, you're trying to hit a point of near exhaustion each set of sprints.
While 20 minutes of any exercise might seem short, you should be exhausted after 20 minutes of interval training. It's designed to be an anaerobic activity, which means that you use chemical compounds like glucose to power your muscles.
When you use anaerobic energy in your workouts your work is more intense but you also can't sustain it as long and have to take rest periods to regenerate your energy. You also deplete your energy stores more quickly.
How They Compare
Compared to steady state, interval training is as good and better in some areas. It's actually safer, according to a 2012 article published in Sports Medicine. Steady state exercise lasts longer which makes it more probable that a heart problem would manifest itself. Long bouts of repetitive activity during a steady state workout also increases the chance of an overuse injury.
Aerobic workouts improve your cardiovascular health, but anaerobic interval workouts might help even more. A 2012 study in Sports Medicine compared people who used steady state exercise with people doing interval training. They found that interval training is more effective at improving your aerobic fitness than aerobic exercise.
The biggest benefit to anaerobic interval training is that you can get your workout done in less time without sacrificing the benefits. If you have the mentality to motivate yourself for each grueling sprint then you can reap the benefits.
Interval training is also the best form of exercise for fat loss, according to a 2008 study in the International Journal of Obesity. They found that steady state workouts were surprisingly bad at helping people lose weight, but the intensity of interval workouts helped give them an extra push and turned on specific metabolic factors to help shed fat.
- Proquest: Evidence based exercise: Clinical benefits of high intensity interval training
- Journal of Endocrinological Investigation: Testosterone responses to intensive interval versus steady-state endurance exercise
- Journal of Applied Physiology: Effect of short-term high-intensity interval training vs. continuous training on O2 uptake kinetics, muscle deoxygenation, and exercise performance
- Human Kinetics: What is Best Practice for Training Intensity and Duration Distribution in Endurance Athletes?