Cardio method descriptions, applications, science, and effects on body composition.
Steady State Cardio. Everyone is familiar with this one. This is easily the most popular form of cardiovascular activity. In Steady State Cardio, your perceived exertion is low to moderate difficulty over a period of at least 30 minutes. Examples include running/walking/jogging on a treadmill without stopping, running a marathon, hiking, etc. Your heart rate is usually 55-70% of your Projected Heart Rate Max over the duration of your activity. While performing Steady State exercise, you are working your Type 1, slow-twitch muscle fibers which are involved in endurance activities and they do not tend to hypertrophy (grow) as much as your other muscle fibers. While the calories you burn doing Steady State Cardio are mostly from fat, you will not burn as many calories as you would doing Interval Training for the same period of time. Steady State Cardio does not elevate your metabolism post-exercise as well as Interval Training but is much easier on your joints. People of all ages are most likely to be able to perform Steady State Cardio consistently without much discomfort.
High-Intensity Interval Training (HIIT). HIIT is growing in its popularity due to its shorter workout times. Most HIIT workouts last 20-30 minutes and are characterized by bursts of maximum activity followed by a short rest period before repeating the activity. Your perceived exertion is high during HIIT with your heart rate falling between 70-85% of your Projected Heart Rate Max. The most popular example of HIIT is running sprints or participation in bootcamp style workouts. During HIIT, you are working the more powerful, more strength oriented type 2 muscle fibers which are more likely to hypertrophy (grow). Even though the percentage of the calories you burn during HIIT that come from fat is low, you will still end up burning more fat during your workout than a Steady State Cardio session of the same duration. You can also burn up to 100 more calories in the 24 hours following your HIIT workout. HOWEVER… you should not do HIIT more than 3 times per week as it is very taxing on your joints and nervous system. In addition to that, you are more likely to injure yourself if you did not properly warm up before performing HIIT since your muscles are pushed harder than in Steady State Cardio. It may also be more difficult for older adults to do HIIT since their joints are not as strong as they once were.
OUR THOUGHTS ON HIIT VS STEADY STATE CARDIO:
HIIT is a clear winner regarding overall calorie burn, however, its application is best served by those not already engaging in heavy weight training (or) by aging athletes. For example, someone who spends 2 hours a day, 5 days a week breaking down their muscles to achieve muscular hypertrophy (bodybuilding) is unlikely to have the ability to recover from their lifting WHILE being able to perform HIIT. In this case, HIIT is more likely to result in overtraining, reduced recovery, and increased stress hormone levels (cortisol). In this circumstance – we would recommend steady state cardio (preferably fasted for fat loss) or while not fasted for (enhanced muscular recovery). For those not already engaged in heavy weight training (or purely strength training athletes), HIIT can be great provided there is a sufficient ramp-up to acclimate the body to the potentially jolting activities that sprinting, burpees, etc have to offer. Insider Tip: A great HIIT workout for those with joint problems or those starting out is “sprints” on the elliptical!
For athletes seeking a hybrid of activities we recommend combining all three elements… weight training (muscular retention is KEY), HIIT (limited, so as not to interfere with weight-training recovery), and steady-state (for heart health, fat loss/maintenance and enhanced recovery).
At CleanFuel Nutrition we strive to provide the best information possible in regards to health/fitness/wellness/nutrition. Thank you for reading and please share!