A lot of people just do their cardio without giving any thought to what their cardio is doing to them. And that's a mistake.
You see, there are different types of cardio that are best-suited to help you meet different kinds of goals. If you choose the wrong kind of cardio, the best-case scenario is that it will take longer to reach your goals. At worst, the wrong kind of cardio can cause you to lose your hard-earned gains.
The Types Of Cardio
So which type of cardio is right for you? I'll get to that in just a moment. First, let's look at the 3 main types:
1. Regular Cardio
This category includes low-intensity, long-duration cardio up to medium-intensity, medium-duration exercise. This means that your workout session lasts from about 30 minutes to an hour or more.
This category also includes exercises such as walking (on the low-intensity end), biking, swimming, jogging, and similar activities. Generally, most people are able to hold a conversation while they're doing regular cardio.
You should choose your exercise intensity and duration depending on your overall fitness level. If you're just getting started, if you're obese, and/or you have a low fitness level, then you might choose something like walking. As your fitness level increases, you can and should crank up the intensity and the duration.
Your body uses fewer calories for this type of exercise than for higher-intensity exercises. However, when you do low or medium intensity cardio, your body utilizes oxygen (hence the name "aerobic" activity), which means you're primarily burning fat for energy.
2. High Intensity Cardio (HIC)
This is where you maintain a high level of intensity throughout most of your session. However, because of the high-intensity, your sessions are relatively short (generally 30 minutes or less).
You can do many of the same exercises you do for regular cardio, except you ratchet up the intensity. Examples include running, hiking and rowing. Generally, it's extremely difficult to hold a conversation while performing a high-intensity workout.
If you're doing a fairly intense workout, then your body will burn up a lot of calories as it taps into its glycogen stores and ATP (adenosine triphosphate) pathway for energy. I won't get into the chemistry of how this works. However, the point is that your body is using sources other than fat stores to create the energy needed for this workout.
3. High Intensity Interval Training (HIIT)
This is a variable intensity session where you alternate between bursts of 100% output followed by active "rest" periods where you drop to about 50% output.
The length of these intervals as well as the type of exercise you're performing depends on your fitness level. For example, someone who's just starting out may jog for 15 seconds and then walk for 15 seconds. Meanwhile, someone with a higher level of cardio fitness may sprint for 30 seconds and then jog for 15 seconds. This cycle repeats for 12-15 minutes (followed by a cool-down period of light exercise).
In all cases, you should be giving 100% effort during the high-output interval. If you're doing this workout the right way, you should not be able to hold a conversation while you're doing it. Plus, you should be pretty wiped out when you're finished.
Because this is a high-intensity activity, it primarily taps into your ATP pathway and glycogen stores for energy. What's more, it burns a lot of calories during the workout session. As an extra bonus, studies suggest that HIIT raises your BMR (basal metabolic rate) for up to 24 hours after the workout.1 That means you'll keep burning calories long after you've left the gym!
Now let's look at your goals to see how these different types of cardio match up with your fitness goals.
Muscle Development
If you're looking for maximum muscle growth while keeping fat to manageable levels, then you'll want to choose low-intensity cardio. It's also a great way to maintain cardiovascular fitness when you're growing muscle. Here's why.
If you primarily use high-intensity forms of cardio for muscle development, then you may end up burning calories that your body needs for muscle growth. If you instead choose low-intensity cardio, then your body taps into your fat stores during the workout, which helps you optimize muscle development while reducing fat.
Tip: If you plan to do cardio and weightlifting on the same day, do your cardio AFTER your weightlifting sessions. That's because the weightlifting will burn up your glycogen stores. By the time you start your cardio, your body will be set to tap directly into your fat stores.
Fitness
If your primary goal is cardiovascular fitness, then you'll want to do a combination of high-intensity cardio and high intensity interval training. That's because high-intensity cardio provides more cardiovascular benefits than low-intensity, long-duration cardio.2
As your fitness levels increase, be sure to:
- Crank up the intensity of your HIC sessions.
- Increase the intensity as well as the length of your high-output intervals when you're doing HIIT.
Leaning Out
If your primary goal is to burn fat while maintaining muscle, then use a combination of low and high intensity cardio. Do high intensity cardio on the day after your peak carbohydrate intake when you have greater glycogen reserves. This will enable you to elevate your heart rate and burn fat, without degenerating muscle. Use low-intensity cardio on the other days and after your weight training sessions.
Cardio And Human Growth Hormone
Human Growth Hormone, a natural hormone produced in the pituitary gland of the brain. HGH is considered "the key" hormone because it controls so many functions. It's responsible for youth, vitality, energy and most of the health benefits we associate with youth. Some research now suggests that you can activate its release through vigorous exercise,3 such as HIIT or HIC.
The reported benefits of Human Growth Hormone (HGH) include:
- Strengthening connective tissue which reduces the probability of injury.
- Weight loss without any reduction in lean mass.
- Reduction of wrinkles by rejuvenating the skin.
- Increasing energy.
- Promotion of muscle growth.
- Improved libido.
- The ability to produce more individual muscle cells.
Conclusion
And there you have it—the three forms of cardio and when you should use them for maximum impact.
Now before we wrap things up, let me throw one more important word out at you: Adaptation.
Here I refer to your body's ability to adapt to any activity you perform repeatedly. And that means you'll work just as hard while seeing diminishing returns (as well as unwanted results like fatigue and muscle degradation).
Fortunately, the solution is easy. All you have to do is force your body to use different muscles by incorporating different kinds of cardio into your weekly routine. This means you should combine 2-or-3 different forms of cardio for best results. For example, I love swimming, weight training circuits, and the elliptical when I'm leaning out.
Physical adaptation isn't the only reason to mix things up. Another bonus is that keeping it fresh keeps it fun for you. And when you're doing something fun, you'll stick with it until you see results! That's why you should seek out activities that you enjoy, such as inline skating, kickboxing, high-repetition circuit training, skipping rope and anything else that floats your boat.
Now pick something and get moving!
References
- King, Jeffrey W. (2001). A Comparison of the Effects of Interval Training vs. Continuous Training on Weight Loss and Body Composition in Obese Pre-Menopausal Women. Thesis presented to East Tennessee State University.
- Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K. (1996). Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Med Sci Sports Exerc, 28(10):1327-30.
- Kanaley JA, Weltman JY, Veldhuis JD, Rogol AD, Hartman ML, Weltman A (November 1997). Human growth hormone response to repeated bouts of aerobic exercise. J. Appl. Physiol. 83(5): 1756-61. PMID 9375348.