Complete Cardio

“Cardio” is the casual term we attach to aerobic exercise, which simply refers to the energy system we’re using during this form of training. When lifting weights, you tend to rely more on the anaerobic energy systems to fuel muscle contractions. With aerobic exercise, which typically refers to rhythmically performed movement at a low to moderate intensity for prolonged periods (think jogging or bicycling), the energy systems at work require oxygen.

Although it’s possible to lose fat with weight training as your lone mode of exercise, to truly maximize fat loss you need to incorporate some form of cardio in your regimen. More importantly, cardio provides health benefits, such as improved cardiovascular health (hence the name “cardio”), reduced risk of diabetes and metabolic diseases, and reduced risk of certain cancers. Plus, cardio can actually help enhance recovery from weight training.

Bottom line: If you want to be fit, healthy and perform at optimal levels inside the gym and out, cardio is a must. That’s why I wrote this Complete Cardio course—to help you make sense of all your aerobic options so you can decide which form of cardio is best for your personal goals and preferences. Do you hate running? No problem. That’s merely one way to do cardio; there are literally hundreds of other alternatives for the jogging-averse.

In this article, I’ll cover all critical areas of cardiovascular training, with a specific focus on activities and programming that will allow you to hang on to your hard-earned muscle while whittling away body fat, getting healthier, and becoming a more well-rounded athlete in the process.

Here’s how the individual sections will break down:

• Part 1: HIIT vs. Steady State
• Part 2: HIIT Programming
• Part 3: Frequency, Timing & Fasted Cardio
• Part 4: Tabata & Cardioacceleration
• Part 5: Power HIIT

After reading this, I hope you’ll come to better understand and appreciate the benefits of cardio and attack your HIIT workouts with the same passion and intensity as you do traditional weight-training sessions. Do this and your hard work is guaranteed to pay off, I promise!

HIIT vs Steady State

There was a time when bodybuilders would only consider doing low- to moderate-intensity steady-state cardio, such as fast walking or pedaling a stationary bike at a moderate intensity. Anything more intense would be considered a big no-no. There were two main reasons for this: First, they believed that more intense cardio would “burn up” muscle tissue (meaning that muscle tissue would be broken down to fuel the exercise). Second, lower-intensity cardio was reported to put you in the optimal fat-burning zone.

Today, we know that both of those lines of thinking are flawed. The concept that high-intensity cardio will burn muscle while low-intensity cardio will spare muscle is quite wrong. In fact, if you just compared the muscle mass of long-distance runners (who spend a good deal of their training at a slower pace for longer periods) to sprinters (who spend a good deal of their training at higher intensities for short periods), you get a good idea of just how flawed that logic is.

When you train at a slow and steady pace for a longer period of time, you’re training your muscle fibers to be more aerobic and have greater endurance. There’s some evidence that suggests that muscle fibers adapt to becoming more aerobic by becoming smaller and weaker, because the smaller a muscle fiber is, the less time it takes for nutrients to travel within the muscle fiber. This speeds up the rate at which nutrients can be burned for fuel.

Another way to consider the misconception that low-intensity cardio performed for longer periods will better spare muscle mass than high-intensity cardio is to compare a high-intensity squat workout done for 5 sets with a weight that limits you to 10 reps per set and a low-intensity squat workout done with a weight that allows you to complete 100 reps per set. Would the higher intensity leg workout of 10-rep sets “burn up” muscle tissue while the lower intensity leg workout of 100-rep sets would better maintain muscle? No. If anything, it would be quite the opposite. In fact, doing higher-intensity cardio, particularly HIIT (discussed below) may actually help to increase muscle mass.

While lower-intensity cardio has been shown to burn a higher percentage of calories from fat, you actually burn fewer total calories with this method. To burn an equivalent amount of calories and fat as high-intensity cardio, you would have to exercise for considerably longer. One obvious problem with doing excessive cardio is time. Most of us barely have time to fit in a 60-minute weight workout, let alone another 60 minutes or longer of cardio. However, another problem with excessively long cardio, particularly for men, is that it has been found to lower testosterone levels.

Yet focusing on just how many calories, and how many calories you burn from fat, during a workout is also a flawed approach. The real benefit of cardio for fat loss is the amount of calories (and calories from fat) you burn after the workout. This is due to the process known as EPOC (excess post-exercise oxygen consumption), which refers to the boost in your metabolism and calorie burning that comes after the workout is over. When you workout, you burn calories to fuel your muscles during the workout. But when the workout is over, your body keeps burning more calories than normal, despite the fact that you’re doing nothing. This is due to the processes involved in recovery from exercise. After exercise, your body must repair damaged muscle fibers, restock muscle glycogen levels and remove lactic acid from the muscles, among other things. All these processes require calories, with a lot of those calories coming from fat. And when it comes to EPOC, this is where HIIT really trumps steady-state cardio done at a lower intensity.

The Science Behind HIIT

High-intensity interval training (HIIT) is a form of cardio that involves intervals of high-intensity exercise (such as running at a very fast pace) interspersed with intervals of low-intensity (walking at a slow pace) or complete rest. This is in sharp contrast to the typical continuous steady-state (slow and steady) cardio done at a moderate intensity, such as walking at a fast pace or jogging for 30 to 60 minutes.

Although HIIT seems to have gained popularity in the last few years, the concept is actually quite old. The origin of HIIT can be traced back many decades to a technique called Fartlek training that was used by track coaches to better prepare runners. The term “Fartlek” is Swedish for "speed" (fart) and "play" (lek), so it means "speedplay", which is essentially what HIIT is. Today, HIIT has crossed over to the fitness industry due to beneficial results that have been established through anecdotal reports and published research studies. In fact, studies comparing HIIT to continuous steady-state cardio have shown that HIIT is far superior for fat loss, despite the fact that it requires much less time.

One of the first studies to discover that HIIT was more effective for fat loss was a 1994 study by researchers at Laval University (Ste-Foy, Quebec, Canada). It reported that young men and women who followed a 15-week HIIT program lost significantly more body fat than those following a 20-week continuous, steady-state endurance program, despite the fact that the steady-state program burned about 15,000 calories more than the HIIT program.

A 2001 study from East Tennessee State University demonstrated similar findings with subjects who followed an 8-week HIIT program (subjects dropped 2% in percent body fat) compared to those who followed a continuous, steady-state program (subjects had no drop in body fat). A study from Australia reported that females following a 20-minute HIIT program that consisted of 8-second sprints followed by 12 seconds of rest lost six times more body fat than a group who followed a 40-minute cardio program performed at a constant intensity of 60% of their maximum heart rate.

A recent study from the University of Western Ontario suggests that you can burn off more body fat than slow and steady cardio with even less than 15 minutes of HIIT. The Canadian research team had male and female subjects follow one of two cardio programs for six weeks. One group of subjects ran slow and steady for 30-60 minutes, three times per week. The other group did four to six 30-second sprints with a 4-minute rest period between sprints three times per week – that’s basically HIIT with an extended rest period between the high-intensity exercise intervals. They reported in a 2011 issue of the journal Medicine and Science in Sports and Exercise that the group doing the sprint intervals lost more than twice as much body fat as the slow and steady group despite the fact that they only did 2-3 minutes of total cardio exercise per day and just 6-9 minutes per week! The sprint interval group also gained over one pound of muscle. This shows that HIIT cardio not only burns off body fat and spares muscle, but it may even help build it.

HIIT Boosts Metabolism

One of the major reasons that HIIT works so well to drop body fat as compared to steady-state cardio appears to be due to the greater increase in resting metabolism following HIIT. Baylor College of Medicine (Houston, TX) researchers reported that subjects who followed a HIIT workout on a stationary cycle burned significantly more calories during the 24 hours following the workout than those who cycled at a moderate steady-state intensity. The East Tennessee State University study mentioned above also found that subjects following the HIIT program burned more calories during the 24 hours after exercise than the steady-state cardio group. A study presented at the 2007 annual meeting of the American College of Sports Medicine by Florida State University (Tallahassee) researchers reported that subjects who performed HIIT burned about 10% more calories during the 24 hours following exercise than those who performed continuous steady-state exercise, despite the fact that the total calories burned during the workouts were the same.

In addition to the increase in resting metabolism, research confirms that HIIT is effective at enhancing the metabolic machinery in muscle cells that promote fat burning and blunt fat production. The Laval University study that found a decrease in body fat with HIIT discovered that the HIIT subjects’ muscle fibers had significantly higher markers for fat oxidation (fat burning) than those in the continuous steady-state exercise group.

A study published in a 2007 issue of the Journal of Applied Physiology reported that young females who performed seven HIIT workouts over a two-week period experienced a 30% increase in both fat oxidation and levels of muscle enzymes that enhance fat oxidation. Research shows that this may be due to an increase in the number of mitochondria in muscle cells (mitochondria is the machinery in cells that burns fat to produce energy). A study from the Norwegian University of Science and Technology (Trondheim) reported that subjects with metabolic syndrome who followed a 16-week HIIT program had a 100% greater decrease in content of the fat-producing enzyme fatty acid synthase as compared to subjects who followed continuous moderate-intensity exercise. In other words, HIIT enhances your body’s ability to burn fat and prevent the storage of fat.

Another way that HIIT appears to work has to do with getting fat to where it will be burned away for good. One study published in the American Journal of Physiology reported that six weeks of HIIT increased the amount of special proteins in muscle cells that are responsible for carrying fat into the mitochondria (where fat is burned away for fuel) by up to 50%. Having more of these proteins in muscle means that more fat can be burned up for fuel during workouts and when resting.

HIIT Builds Muscle

As I’ve already mentioned, HIIT will not only help you maintain your muscle, but can actually help build muscle mass. A study published in the Journal of the International Society of Sports Nutrition reported that male subjects following a six-week HIIT program (done for 15 minutes per day at a 2:1 work-to-rest ratio, 3 days per week) while supplementing with beta-alanine gained over two pounds of muscle, despite the fact that they never lifted weights during the program. The 2011 study on sprinting from the University of Western Ontario discussed above reported that those performing 30-second sprint intervals actually gained some muscle mass, while the slow and steady cardio group did not.

Another study from the UK reported that obese subjects following a low-carb diet lost muscle, yet those performing HIIT along with the low-carb diet were able to maintain muscle mass. This makes sense when you consider that weight training is technically a form of HIIT – you have short periods of high-intensity exercise interspersed with periods of rest.

One reason why HIIT may lead to greater gains in muscle mass may be due to the anabolic hormone testosterone. New Zealand researchers had competitive cyclists complete four weeks of HIIT training involving 30-second sprints on a stationary cycle separated by 30 seconds of rest. One group sprinted with high resistance on the pedals, making it harder to pedal, while the other group used a lighter resistance, which was easier to peddle. Both groups peddled as fast as they could during the 30-second sprints. They found that the men peddling at the highest resistance increased their testosterone levels by almost 100%, while the group peddling at a lighter resistance only increased test levels by about 60%.

Another reason for both the health benefits of HIIT and its benefits on muscle mass, not to mention fat loss, has to do with improved insulin sensitivity. When you improve insulin sensitivity, not only does this help to keep you lean and prevent diabetes, but it can also aid muscle growth. Insulin is an anabolic hormone that acts on the muscle cells to increase muscle protein synthesis, decrease muscle protein breakdown and drive more glucose, amino acids, creatine and carnitine into muscle cells.

Here’s a study to back these claims up: Watt University (Edinburgh) researchers had subjects follow a two-week training program with workouts consisting of just four to six 30-second sprints on a stationary cycle. Sprints were separated by four minutes of rest. They discovered that at the end of the two weeks, the subjects’ blood glucose and insulin levels were reduced by almost 15% and 40%, respectively, following the consumption of 75 grams of glucose. Insulin sensitivity, which is the measurement of how well insulin does its job at the muscle cells, improved by about 25%.

Without a doubt, there’s a mountain of research that says HIIT is a better option for getting lean and maintaining (and even building) muscle mass than your typical low-intensity 45-minute treadmill session. But this isn’t to say that you should never do steady-state cardio. If you enjoy jogging, hiking and/or cycling, then, by all means, include that exercise in your program. However, you should still consider adding a few days of HIIT into your routine. This will not only improve your physique, but will also improve your performance when you do steady-state cardio.

Now that I’ve sold you on HIIT cardio, it’s time to look at some actual HIIT workout programming. Below, you’ll find my “beginner-to-advanced” HIIT routine, which is great for anyone still getting used to the high-intensity nature of HIIT training.

Cognitive Benefits of HIIT

In addition to the benefits of torching body fat, boosting performance, and enhancing cardiovascular health, HIIT could also be a cognitive game-changer by boosting reaction time and giving your brain a serious speed boost.

In a recent study published in the journal Strength and Conditioning Research, exercise scientists set out to explore the cognitive benefits of HIIT. They gathered 27 men and 31 women and had them undergo a 20-minute HIIT workout. The workout consisted of 20 seconds of intense exercise followed by 20 seconds of rest, incorporating bodyweight exercises or light free weights. Meanwhile, another group had a calm 20-minute rest by reading before taking reaction time tests.

The results were nothing short of fascinating. Those who engaged in HIIT before the tests showed a whopping 12% faster reaction time compared to those who rested quietly. Plus, their brain processing times were 10% faster than the resters. That's a huge cognitive advantage.

Why does this matter? If you're involved in sports where split-second decisions are make-or-break – think baseball, basketball, football, tennis, boxing, martial arts, the list goes on – incorporating 10 to 20 minutes of HIIT into your pre-competition routine could be a game-changer. It's not just a warm-up; it's a strategic move to sharpen your reaction time and up your game.

HIIT Programming

HIIT can take on many different forms and be done with virtually any equipment or absolutely none at all. You can do HIIT while running on a track or a treadmill, with a stationary bike or a stair stepper, with calisthenics and your own bodyweight or with explosive exercises done with free weights.

There’s almost no wrong way to utilize HIIT other than not doing it at all. And while there are numerous exercises that you can do with HIIT, there are also numerous different ways to employ the concept. Below are some of the more effective ways I’ve found to use HIIT.

Standard HIIT

By the phrase "standard HIIT," I’m referring to doing a scheduled block of time of just HIIT. Some evidence suggests that when doing HIIT, a 2:1 ratio of work to rest (high-intensity exercise to low-intensity exercise or rest) provides the best benefits in performance, fat loss and health. For example, you could sprint as fast as possible for 30 seconds and walk for 15 seconds. Or you could jump rope for one minute and rest for 30 seconds. Of course, studies like one out of University of Western Ontario that showed positive results from sprinting for 30 seconds and resting for four minutes suggests that the benefits are substantial even with a HIIT work-to-rest ratio of 1:8. Despite that study, I would still recommend shooting for a 2:1 ratio. If that’s too much for you to handle at first, start off with a 1:2 or 1:4 ratio (or even 1:8 if you need to) and gradually increase the ratio over time.

The intensity of the high-intensity intervals can be something that’s tightly prescribed, such as a certain percent of your maximum heart rate. Or it can be loosely determined based on what feels intense to you. Because I prefer to do a variety of gym exercises, including moves like dumbbell cleans, kettlebell swings and bench step-ups, checking your heart rate manually, or even on a heart-rate monitor is fairly impractical. So I prefer to use a simple 1-10 RPE (rate of perceived exertion) scale like this:

Rate of Perceived Exertion (RPE) Scale
Use the following scale when rating your HIIT intervals:

Rate                                          Description
0                                                nothing at all
1                                                very easy
2                                                easy
3                                                moderate
4                                                somewhat hard
5                                                hard
6
7                                                very hard
8
9
10                                              very, very hard

During the high-intensity work intervals, you should be somewhere between 6-9 on the RPE scale. Stick with the lower end of that range when just beginning, with the goal of increasing your RPE as you go. If you aren’t taking complete rest between the work intervals, your RPE during the low-intensity (“rest”) intervals should be somewhere in the 1-3 range.

You should also shoot to increase the block of total time spent doing HIIT as you progress. If you start with just 10-15 minutes at first, that’s fine. But your goal should be to slowly increase your total time.

Beginner-to-Advanced HIIT Program

The following HIIT program is designed to progress someone from being a HIIT beginner to the intermediate level of HIIT proficiency. This can be done with any equipment, such as a treadmill, jump rope, pair of dumbbells, kettlebell, exercise bands, medicine ball, TRX or just your body weight and calisthenics.

The suggested time of each phase is not carved in stone. If you feel you need to spend more than two weeks at a particular phase before moving up, then, by all means, do that. Or if a phase seems too easy and you want to jump right up to the next phase, then do so. This program starts with a 1:4 work-to-rest ratio in Phase 1 for a total workout time of just under 15 minutes. Then in Phase 2, it bumps up the amount of time in the “work” phase to bring the ratio up to 1:2 and the total workout time to 17 minutes. In Phase 3, the rest ratio is cut in half to bring the ratio up to 1:1 and the total workout time goes up to 18.5 minutes. And finally, in Phase 4, the rest ratio is cut in half again to get the ratio up to 2:1 and the total time at 20 minutes.

Note: One work interval plus one rest interval = one complete interval.

Phase 1 (1:4 Work-to-Rest Ratio)

Phase 2 (1:2 Work-to-Rest Ratio)

Phase 3 (1:1 Work-to-Rest Ratio)

Phase 4 (2:1 Work-to-Rest Ratio)

This program provides an example of “standard” HIIT workouts. Very straightforward, but also very challenging and very effective. If your HIIT workouts look more or less like these, you’ll be in great shape. But if you like the thought of pushing the envelope and varying your HIIT training to maximize results, I’ve got more in store for you.

Frequency, Timing, and Fasted Cardio

One question that gets asked a lot by weight-training enthusiasts is: What’s the minimal amount of cardio I need to do to see fat-loss results? Of course, this is usually asked by those who think of cardio as only the slow and steady type done on a treadmill or stationary bike. Most people who enjoy lifting tend to loathe cardio. But once they realize that cardio can be done with weights, HIIT style, they end up asking: How much is too much?

There’s evidence both from research and anecdotal reports that the minimum amount of cardio you should do each week is three to four workouts.

One study put 90 male and female subjects on an eight-week program that consisted of doing cardio for 30 minutes straight. They divided the subjects into groups based on how often they exercised each week. One group served as a control and did no exercise; a second group did the cardio workout less than twice a week; a third group did the workouts two to three times per week, and the fourth group did cardio four or more times per week.

They discovered that at the end of the eight weeks, only the last group performing cardio four or more times per week lost a decent amount of body fat (almost 15 pounds of it). Of course, the subjects weren’t weight training in addition to doing cardio and they also weren’t doing HIIT, so it’s hard to say from this study precisely how many days of cardio you need in addition to weight training. Anecdotal reports suggest a minimum of three HIIT cardio sessions per week in addition to weight training. But obviously, the more you do each week the greater the expected fat loss. In fact, you can do seven days of cardio per week if you prefer. And that can be seven days of HIIT, mind you.

You may be worried that doing HIIT that often will lead to overtraining. However, as long as you’re switching up the exercise choices, you can do HIIT every day of the week. After all, it’s typically done for only 15-30 minutes—and that’s not even total exercise time. One study in athletes found that those using HIIT every day experienced no decrement in performance. So much for overtraining.

The Best Time of Day to Do Cardio

Whether you do your cardio immediately before you lift weights, immediately after, during weight workouts (such as cardioacceleration, discussed below) or in an altogether different training session matters little to the effect it will have on fat loss. The most critical aspect of scheduling your cardio is when you’ll be most consistent doing it.

I would argue that it's best to combine both at the same time—with cardioacceleration. That way, you save time and you maximize fat burning and recovery while you get bigger, stronger and leaner. But cardioacceleration may not be for everyone. Some still prefer to keep their cardio and weightlifting separate. In that case, I typically would argue to lift weights first while you are at your strongest and not fatigued, so that you can lift with more strength and intensity. Plus, there is some evidence that doing cardio after weights may aid fat burning better, but even that's debatable since the true fat-burning benefits of cardio come after the workout is done (especially with HIIT). And some like using cardio as a warm-up session to increase their body temperature, which evidence shows can help to increase muscle strength, especially during colder months. This can also be done with my Power HIIT.

One cautionary study out of Australia measured the height and volume of subjects' intervertebral discs (spinal discs) before and after 30 minutes of moderate-intensity running on a treadmill. They discovered that after the run spinal disc height and volume were decreased by about 7%. The researchers suggested that this can decrease the load-carrying capacity of the spine. In other words, if you lift a heavy enough weight while your disc volume is reduced, you could be at a higher risk for a back injury. So depending on the volume of your workout, if you're intent on separating your lifting from your cardio consider keeping the cardio work for after you hit the weights. Not only will this allow you to lift heavier and more intensely, build more muscle and burn more fat, but it can also help you to prevent a back injury.

You may have read online that one study suggests that doing cardio first is better for muscle growth, but before you believe what the study concluded and what the media may be telling you, let's take a closer look at the study. Researchers from Brazil tested the testosterone response in weight-trained men when they did a weight-lifting workout followed by 30 minutes of moderate cardio (on a stationary bike) or when they first did the 30 minutes of cardio followed by the weight workout.

Their main finding was that when the subjects lifted weights first and then did cardio immediately after, their testosterone levels peaked during the weight-lifting, but then dropped during the cardio. However, when they did the cardio session first, testosterone rose during the cardio workout and then continued to rise during the weight-lifting workout that followed.

These results have made many "experts" jump to the conclusion that doing cardio before weight lifting is the better option for muscle growth because the anabolic hormone testosterone continues to rise throughout the entire workout. And when they lifted weights first, their testosterone levels peaked during the weightlifting but then dropped during the cardio. That's not good, right? Actually, it may be VERY good that blood levels of testosterone decreased.

Measuring testosterone levels in the blood only tells you how much testosterone is in the blood. Yet testosterone does not do much in the blood other than travel to the tissues it is going to influence like muscle fibers. It's in the muscle fibers that testosterone boosts muscle growth, not in the blood. Research shows that weight training increases the number of androgen receptors in your muscles. Androgen receptors are the receptors in muscle cells that testosterone binds to in order to instigate muscle growth.

With more androgen receptors in your muscle, there will be more testosterone entering the muscle cells. And if more testosterone enters the muscle cells, that means that testosterone levels in the blood will drop. In fact, the Brazilian researchers explained that the testosterone levels may have dropped after the weightlifting session during the cardio session due to a greater uptake of testosterone by the muscles. So it's hard to know what the real take-home point of this study is without seeing what is going on in the muscle cells. Yet the researchers did not look at that piece of the puzzle.

The bottom line is to do cardio whenever you will get it done. If you tend to skip cardio when you leave it to after your weight workout, then consider doing it before or during your weight-training session or at a completely different time or day. There are two options when it comes to doing cardio during your weight-training workouts.

Option one is to do cardioacceleration, which involves a 30-90-second bout of high-intensity cardio in between every lifting set. Or you can do a bout of HIIT in between muscle groups. For example, if you train back, biceps and calves in one workout, you could do 10 minutes of HIIT in between back and biceps, in between biceps and calves and after calves for a total of 30 minutes of HIIT. Several studies have reported that breaking up your cardio into several smaller sessions allows you to burn more calories during the workout as well as more total calories and more calories from fat after the workout is over. This has also been shown to allow subjects to lose significantly more total fat over a prolonged period.

The Truth About Fasted Cardio

Another misconception about cardio is that the best time to do it is first thing in the morning on an empty stomach. Research does, in fact, show that you burn more total fat when you do fasted cardio; some research shows that you can burn 20% more fat when you do fasted cardio in the morning.

However, as mentioned above, how many calories and how many calories you burn from fat during the exercise shouldn’t be the major focus. Research suggests that when you burn carbs during exercise, you burn more fat after the exercise is over, and when you burn more fat during exercise you burn more carbohydrates afterward. In other words, it’s more about the total amount of calories and fat you burn throughout the day, not just during exercises. Research also suggests that whether you exercise first thing in the morning fasted or fed, you end up burning the same amount of calories total throughout the day.

Generally speaking, your best bet is not to worry about doing cardio first thing in the morning or fasted. If doing cardio first thing in the morning is best for your schedule, then, by all means, do it then. But it’s advisable to have at least a protein shake (like Pro JYM), if not both a protein shake and some carbs (such as fruit), before the workout. If you’re trying to limit carb intake, you may want to avoid the carbs until after the workout is over.

And of course, to maximize intensity during the workout and promote long-term gains in size, strength, and fat-burning, I suggest taking Pre JYM before all HIIT workouts. Afterward, Pro JYM and Post JYM will help ensure adequate muscle recovery so you’re able to train hard on subsequent days.

With all that being said, there’s one time when fasted cardio may be a strategy you want to employ. Anecdotally, I’ve found that fasted cardio can work well for men with body fat that is in the low single digits (somewhere around 5%-6% body fat) or females with body fat in the low teens (somewhere around 13%-14% body fat) who have one stubborn area of unwanted body fat.

Many males, especially older males, tend to hold fat on the lower back and obliques. Many females tend to hold fat on the hips and thighs. And no matter how hard they train and diet, this fat holds on for dear life. Over the years, I have found that once they’ve dropped the majority of the subcutaneous fat on the rest of the body, fasted cardio does seem to work well to rid that last bit of fat. Although there’s no direct data to look at, it may be that when a person is so low in body fat and only has fat on certain stubborn areas, exercising in a fasted state may be the spark that those resistant fat cells need to release that stored fat so that it can be burned away for good.

But if you’re a male at about 8% body fat or more, or a female at about 16% or more, then fasted cardio is likely not going to make much of a difference in your fat-loss efforts. Do cardio, preferably some form of HIIT, consume a clean diet, and the fat will come off.

Next, I’ll go more in-depth on two of my favorite ways to employ HIIT in my programs: Cardioacceleration and Tabata intervals.

Tabata and Cardioacceleration

Achieving significant results with any training routine, cardio or otherwise, requires a certain level of intensity. Nobody gets shredded by taking leisurely walks in the park. Staying in your comfort zone and “taking it easy” won’t cut it. That’s the whole premise behind HIIT cardio and two forms of HIIT that are particularly effective for boosting intensity are Tabata intervals and cardioacceleration.

Tabata

Tabata intervals are a method of HIIT that uses a 2:1 work-to-rest ratio in a very specific format: alternating 20 seconds of all-out max effort work with 10 seconds of rest for exactly four minutes, eight total intervals. That’s one round of Tabata. The point is not to fall into a specific heart-rate range, but rather to try and go as intense as possible, shooting for an RPE of about 9-10 on all work intervals.

Tabatas are named after the Japanese scientist who created them, Dr. Izumi Tabata. As the story goes, Tabata was looking for a better way to train his athletes on the Japanese speed-skating team. What he discovered was that when he had athletes perform eight cycles of 20-second high-intensity exercise intervals followed by 10 seconds of rest, they increased both their aerobic (endurance) and anaerobic (quick power) capacities – the two things that speed skaters need. In other words, whether you’re an endurance athlete like a cyclist or a power athlete like a weightlifter, Tabata offers you benefits because it trains both major metabolic pathways: those that provide endurance and those that provide explosive energy. That’s why so many athletes have taken to doing Tabata intervals. And of course, Tabata works very well for fat loss.

You have many options for how to work Tabatas into your program. You can choose anywhere from four to eight exercises and do them as a block of Tabatas for a total cardio workout time of 16-32 minutes. Or you can do one to two exercises Tabata style in between muscle groups. These are a couple of ways I like to use them.

For example, if you trained chest, triceps, and abs in one workout, you could start with Tabata jumping rope to warm up. Then, after finishing chest, do Tabata kettlebell swings followed by Tabata bench step-ups before training triceps. After triceps, you could do Tabata dumbbell cleans and Tabata jumping jacks before training abs. Then do two more Tabata-style exercises after abs for a total time of 28 minutes of Tabata HIIT.

A typical Tabata exercise would look like this, using kettlebell swings as an example:

Again, you can plug any number of different exercises into the Tabata format. Just remember, Tabatas are based on all-out intensity during the 20-second intervals. That’s why it only lasts four minutes. If a round of Tabatas feels easy, you're not going hard enough.

For more specific examples of how to incorporate Tabata intervals into a workout, check out my Super Shredded 8 program.

Cardioacceleration

Cardioacceleration refers to doing intervals of cardio (anywhere from 30-90 seconds) in between sets of lifting exercises. For example, on chest day, you would do one set of the bench press and then, instead of sitting on the bench and resting, you’d perform 30-90 seconds of high-intensity cardio. Then you’d do the next set of bench presses and continue in this manner throughout the entire workout.

Multiply those 30-90 seconds of cardio by the number of sets you complete in each workout and it adds up. If you train chest, triceps, and abs and do 12 sets for chest, 9 sets for triceps and 9 sets for abs (30 total sets), and complete 60 seconds of cardio between each set, you’ve just completed 30 minutes of high-intensity cardio during your chest, triceps and abs workout. That means you don’t have to spend extra time doing cardio after the workout is over or on a separate day. You can go home knowing you’ve done your weight training and your cardio all in one fell swoop.

Cardioacceleration is based on a study by University of California-Santa Cruz researchers that reported in the Journal of Strength and Conditioning Research that trained subjects completing 30-60 seconds of cardio in between sets of weight training for over two months recovered better than those resting normally between sets. Not only does this method of HIIT allow for better recovery after workouts but, believe or not, it allows for greater recovery between sets as well.

It’s rather shocking at how well this technique works to aid recovery during a workout. In fact, in my programs, it has helped thousands of men and women break PRs while getting leaner at the same time. Many people worry that doing cardio in between sets will decrease their strength on lifting exercises, but as I’ve found, once the body adapts to the cardioacceleration, it actually appears to enhance recovery between sets and strength.

Another nice thing about cardioacceleration is that you don’t have to use the treadmill or other typical forms of cardio equipment. You can do the cardio interval right there at the station you’re training. For example, if you’re doing the bench press, you can do 30-90 seconds of bench step-ups on the bench between sets. If you’re doing dumbbell flyes, then do dumbbell cleans for cardio right next to your bench. This way you don’t lose your spot in a busy gym.

Start off on the low end of the scale with 30 seconds of cardio in between sets. Over time, you can increase that by 15 seconds until you are up to doing 90 seconds of cardioacceleration in between sets.

Power HIIT

It may not be peanut butter and jelly or Batman and Robin, but it’s a pretty great combination nonetheless: power training and high-intensity cardio.

Power HIIT involves doing intervals of explosive exercises with short intervals of rest. The exercises can include anything like power cleans, snatches, jump squats, power push-ups and kettlebell swings, just to name a handful. These are exercises that are typically done to develop explosive power, strength, and speed for sports performance. Combining them with HIIT allows you to build more muscle power while increasing fat loss and cardiovascular conditioning.

With Power HIIT, both the exercise intervals and the rest intervals last 20 seconds. This time frame typically allows you to complete about 3-4 reps during each exercise interval, the perfect range for building power. Then, you get an equal amount of time to recover to help you better maintain power during the next work interval.

This 1:1 work-to-rest ratio can also help to build more muscle size and strength by boosting testosterone levels. One study out of New Zealand found that cyclists performing 30-second high-powered sprints separated by 30 seconds of rest (a 1:1 ratio) increased their testosterone levels by up to 100%. This, of course, can translate into more strength and size as well as better fat-burning by boosting the metabolism.

Power HIIT Programming

For each exercise in my Power HIIT scheme, you’ll do three exercise/rest intervals and then move on to the next exercise. This way, you’ll work at building power on each exercise without completely exhausting your muscles for other movements in the workout.

The power exercises used with Power HIIT are done in a very fast and explosive manner. These fast reps primarily recruit the fast-twitch muscle fibers, the ones that grow the biggest, strongest and fastest. So it’s easy to understand how using HIIT workouts can help you build muscle and power. But the fast-twitch muscle fibers also burn the most calories when you use them. Plus, most of the exercises used in Power HIIT use a large number of muscle groups, which also maximizes calorie burning.

Start each Power HIIT workout with a 5-minute HIIT warm-up of jumping rope or jumping jacks. This warm-up should be done in typical HIIT fashion at a 2:1 ratio of jumping to rest. In this case, it’s 30 seconds of jumping followed by 15 seconds of rest, seven times through. (If you do the Power HIIT workouts after weight training, feel free to skip this 5-minute warm-up if you feel sufficiently warmed up already.)

After the jumping rope/jumping jacks HIIT warm-up, go right into the Power HIIT workout. Do three 20-second sets of each exercise, taking 20 seconds of rest between sets and exercises. In Workout A below, you start with squat jumps for building leg power. Then you move into power push-ups for building chest and triceps power. Next are power cleans done with dumbbells or a barbell, then it’s on to medicine-ball overhead throws. If you don’t have a medicine ball, you can simply do band shoulder presses or even barbell or dumbbell push presses. Finish with band standing crunches to build strength and power in the midsection. If bands are a problem, you can do a medicine ball crunch throw or even a regular crunch done with explosive reps on the positive rep.

Since you’ll want to repeat this workout several times a week, I’ve provided you a “Workout B” so you can alternate between the workouts without hitting the same exercises in the same order every time. In Workout B, you start with the kettlebell snatch. You can also do this with a dumbbell if kettlebells aren’t available. Then you move into the band sprint, calf jumps and kettlebell swings (which can also be done with a dumbbell). You’ll finish with the band woodchopper (or you can use a cable or a dumbbell) to build rotational power in the upper body and strengthen the core. Since you have to do both sides of the body, instead of doing three sets of 20 seconds each, do two 20-second sets of woodchoppers per side for a total of four sets.

In both Workouts A and B, you’re doing five exercises for three 20-second sets each (except in Workout B where you have an extra set for woodchoppers) with 20-second rest periods. This equals a total of 10 minutes. With the jump rope HIIT work for five minutes, that’s a total of 15 minutes of intense cardio that not only burns fat and enhances cardiovascular fitness but also builds overall muscle strength, power, and mass. If your goal is to maximize muscle mass, strength and power and cardio is more an afterthought, keep it at this duration. Work on increasing the weight you use on the exercises and/or the number of reps you can bang out in those 20 seconds.

If fat loss is your primary goal, as well as the cardiovascular benefits that this novel form of cardio offers, then you’ll want to progressively bump up your total time of Power HIIT. I’ve offered you three stages to work up to, each of which increases total Power HIIT time. Go at your own pace. When the 15-minute workout is no longer much of a challenge, start on Phase 2, which brings your total HIIT workout to almost 20 minutes. When that becomes less challenging, it’s time to really get serious and jump into Phase 3, which brings your total workout time to 25 minutes.

You can do the Power HIIT either at the beginning or end of your workouts or on a separate day altogether. It all depends on your goals. If you’re using Power HIIT to boost muscle power and athletic performance, do this workout at the start of your training session or on a separate day from your usual weight training. If fat loss is the primary goal with Power HIIT, do it either at the beginning or end of your weight workouts or on a separate day from weights.

Power HIIT Warm-Up

Jump Rope/Jumping Jacks Warm-Up (30 sec/15 sec) – Do this workout at the start of each Power HIIT workout, regardless of the phase you’re in:

Total time: 5 minutes

Power HIIT Workouts (20 sec./20 sec.)

Phase 1, Workout A (Total time: 9 min, 40 sec.)

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Phase 1, Workout B (Total time: 10 min, 20 sec.)

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Phase 2, Workout A (Total time: 13 min., 40 sec.)

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Phase 2, Workout B (Total time: 14 min, 20 sec.)

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Phase 3, Workout A: (Total time: 19 min, 40 sec.)

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Phase 3, Workout B: (Total time: 20 min, 20 sec.)

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Stretching Before Cardio

If you haven't heard my advice on stretching, then hear me now—do NOT perform static stretching (where you stretch and hold like the sit and reach stretch) before you lift weights. The reason for this is that research has shown that stretching the muscles with the typical static stretching can significantly reduce your muscle strength and power. Plus, research confirms that doing static stretching does NOT reduce the risk of injuries. And research also shows that you can increase your flexibility far more when stretching after the workout.

But what about stretching for cardio workouts? That may depend on whether your goal is to perform better or burn more calories, according to a new study from Cal State Fullerton. They had trained male and female cyclists perform a 30-minute cycling test on a stationary cycle. In one trial they performed about 15 minutes of static stretching for their legs. In the other trial, they did no stretching and just sat for 15 minutes before the cycling test.

They reported at the 2011 Annual Meeting of the National Strength and Conditioning Association that when they stretched before cycling they used up more energy during the cycling test.
In other words, they burned more calories, about 12% more, when they stretched before cycling.

Jim's Take-Home Message

If you are an endurance athlete training for competition, then the take-home point here is to not stretch before cardio. You will be less efficient and that will negatively effect your performance: just like stretching does when done before weight workouts. However, since few of us are endurance athletes, and 99.9% of us do cardio just to burn up calories and burn off fat, the obvious take-home point is to do your stretching before cardio. This can help you to burn more calories and fat. If you do cardio after weights, then consider doing your stretching in between – after the weight workout, but before the cardio workout.

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  Complete Cardio Part 4: Tabata & Cardioacceleration

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