Cardio, by definition, simply means you’re doing a rhythmic activity with your body that will raise your heart rate into your target heart rate zone.
Types of Cardio: Steady State vs. HIIT Training
Steady State Cardio:
Steady-state cardio is a continuous, steady effort, as opposed to an interval workout where you vary your energy output. Any cardiovascular/aerobic activity that is sustained for an extended time (with a minimum of 10 minutes) at a fixed intensity qualifies as steady-state training.
Typically, your heart rate will remain between 65%–80% of your MHR* for an extended period of time. Running, cycling, and rowing, are great examples.
If your goal is to sustain your body in activity for a long period of time, then steady-state cardio is best to increase your endurance.
High-Intensity Interval Training (HIIT) calls for repeated timed sessions of short duration, high-intensity exercise intervals paired with periods of lower intensity intervals of active recovery. For example, 20 seconds of an exercise (such as burpees) at the participant’s top performance, followed by 10 seconds of light jogging would qualify as part of a HIIT Training format. Stringing several of these together is what builds a complete HIIT training circuit.
Specifically, HIIT can be any exercise where, in recurring intervals, your heart rate spikes to 80%+ of MHR*.
If your goal is to build up the highest level of performance and speed, then HIIT intervals are the way to go.
Which one is better?
Both types of cardio have benefits to increase your fitness ability. Choosing one over the other is really a matter of individual health goals. Here are a couple of considerations:
Exercise that consumes more oxygen burns more calories.
With HIIT training, you use the body’s reserves of energy during the workout. After the workout, your metabolism will stay elevated and will continue to burn calories for hours after a workout because of something called excess post-exercise oxygen consumption (EPOC). During this time, your body works to replace energy and tries to repair muscle proteins broken down during exercise.
Steady-state training is the most effective way to prepare for an endurance event such as a marathon, ultrarace, or triathlon. It is known to increase cardiac efficiency and enhance aerobic capacity. Steady-state training has the ability to use fat as an efficient fuel source, vs. muscle glycogen that is used for higher-intensity exercise.
*How to figure Max Heart Rate (MHR)
Your MHR = 220 MINUS Your Age = Maximum Heart Rate
Your maximum heart rate is defined as the upper limit of what your own cardiovascular system will handle during a workout and/or physical activity. Pushing your heart rate over this number can cause serious damage and injury to your body.