Cardio vs. Strength Training

Which is the best form of exercise for you?

While shows like The Biggest Loser are visually compelling, with contestants’ progress tracked using oversized scales, there is an unintended consequence of defining the winner as the person who loses the most weight: the ‘victor’ also ends up losing the most muscle.

The problem is an obsession with weight loss to the exclusion of every other metric.  The number on the scale does not provide any insight into the actual composition of the body.  

You may be wondering: how much muscle do the contestants on The Biggest Loser actually lose?  What is the relative contribution of fat and muscle to body weight?  In other words, what is your body fat percentage? If excess body fat is a major cause of metabolic and cardiovascular conditions ranging from heart disease to diabetes to sleep dysfunction, it’s safe to say this is the critical tissue we want to expel from the body.

Whether you’re concerned primarily with health or weekend pool parties, abdominal fat is like the kid who habitually pees in the pool - nobody wants him there.  This fat generally comes in two forms:

• Subcutaneous fat: Located directly beneath the skin.  Reduces muscle definition, but generally behaves like fat everywhere else in the body – it isn’t beneficial to health but does not pose any unique threat either.
• Visceral Fat:  Located inside the abdomen surrounding internal organs.  Visceral fat can be can be uniquely detrimental to health.

Scientists have thoroughly documented visceral fat’s danger in terms of its capacity to increase blood pressure, stress hormones, blood sugar instability, and cardiovascular risk.  However, new research is illuminating another contributing factor: lipotoxicity, a metabolic syndrome related to a high body fat percentage. Organs particularly susceptible to complications resulting from lipotoxicity include: kidneys, liver, heart, pancreas, and skeletal muscle.  Issues that can result from lipotoxicity involve an impaired ability to regulate insulin, blood sugar, and cholesterol.

A worldwide paradigm shift needs to happen, yesterday!

The Reality of Weight Loss.  When you start thinking about weight loss in terms of body composition instead of just a number on the scale, you gain access to a greater level of control over your health.  The table below shows approximately how much of each body tissue type we lose whenever we go down in weight.

Type of Tissue Lost | Percentage of Loss

Fat Mass | ~ 75-80%

Skeletal Muscle | ~ 20-25%

Bone | ~ 0.5-1 %

It’s important to reiterate that any time we use the general term “weight loss” we are failing to consider which type of body tissue we’re actually losing.  For example, during periods of caloric restriction, much of the mass we lose is made up of skeletal muscle. If your scale weight drops from 180 lbs. to 160 lbs., at least some portion of this 20 lbs. is going to be muscle – likely around 20% of weight lost.  That is, unless you are using techniques proven to mitigate muscle loss and ensure the weight lost is comprised almost entirely of body fat. Practitioners refer to this as high-quality weight loss.

But why is it important?

Our body composition goals should reflect a desire to lower risk of metabolic and cardiovascular disease, while improving physical and physiologic function.  In other words, gain muscle while losing fat.

As explained later in Chapter Four, “Omnivore’s Dilemma”, muscle is particularly important during times of weight loss if the idea is to sustain body fat losses for long periods while achieving a toned physique.

Whether your goals are looks, health, or both, you cannot deny the importance of skeletal muscle.  The benefits are many:

• Locomotion: muscle provides the capacity to navigate dynamically through space.  Locomotion is important for physical fitness and self-reliance.
• Strength: muscle provides the ability to impose adequate force on the external environment.  When you can oppose external resistance you become better equipped to prevent injury.  Let’s face it, life is easier when you’re strong.  
• Regulation of Blood Glucose: muscle is a prominent site of glucose disposal, making it a storage depot for energy (glycogen).  This helps stabilize blood sugar levels, which is important for the prevention of metabolic disorders such as diabetes.  In other words, the more muscle you have, the easier you can handle carbohydrates in a way that minimizes the accumulation of body fat.  
• Regulation of Blood Lipids: muscle is the machinery that mobilizes fat to meet energy needs.  The more muscle you have, the more tissue you have that metabolizes fat.   
• Resting Metabolic Rate (RMR): RMR (same as Basal Metabolic Rate) is the rate at which your body burns calories while at rest. Increasing muscle will rev up your metabolism, which will elevate your RMR as a result.

Muscle is a metabolic powerhouse, accelerating fat loss and acting as a repository for sugar and fat, which could otherwise accumulate in harmful amounts.  That makes muscle an essential component of sustainable fat loss, weight management, and long-term health.

How do we prevent muscle loss during a diet?  

Your body interprets a caloric restriction as a dietary stress or energy shortage.  Building new muscle is an energy-consuming process, but when operating under a caloric deficit your body only has access to scarce resources.  Consequently, we experience a reduction in muscle remodeling (anabolism) as our body consumes internal energy stores to bridge the gap between dietary energy coming in and energy being expended.   Although the majority of this energy is gained by metabolizing glycogen (stored carbohydrate) first, followed by body fat, under extreme caloric deficits some energy will come from breaking down muscle protein.

We don’t want that.  Our metabolism is already slowing down from the caloric deprivation, and so losing the tissue most influential in sustaining metabolism is the last thing we want.

Fortunately, there are two stimuli that can rescue muscle from this fate and in some unique cases, completely reverse it.  These are resistance training and protein ingestion which, when used independently of each other, can meaningfully augment muscle protein synthesis in the face of a caloric deficit.  However, when implemented together they have a uniquely synergistic relationship. We will discuss this in detail in Chapter Four.

If resistance training is one of the most important methods for body fat loss (second only to nutrition), then what can we do to emphasize its effect using our limited time in the gym?

The reality is that while you can dive as deeply as you like into the science of fitness, for most of us, simply learning the principles of weight training will empower you to achieve SHORTER and MORE EFFECTIVE workouts.

Would you like to:

• Spend no more than 25 minutes in the gym
• Achieve dramatic reductions in body fat
• Maintain or develop muscle to achieve the fittest physique of your life

If you’d like your weekly workout routine to be an energy-producing and not an energy-consuming process, keep reading.  Once we establish some key principles that will maximize your workouts' effectiveness, at the end of the chapter we'll bring it all together to create an actionable plan for you.

Resistance training is any exercise that causes the muscle to contract against an externally imposed resistance.  When we repeatedly subject our muscles to resistance, we force them to adapt in order to prepare for similar stresses in the future.  When you first start training, you can take an inconsistent approach and still see dramatic benefits because of the novelty of muscular stress.  However, after you’ve been training for a while (> 6 months or so), a methodical approach becomes important, whether your goal is increased strength, size, or endurance.  That said, you will need to tailor your training regimen according to your specific objective.

Muscle adaptation occurs via a process of catabolism (breakdown) in response to resistance training, followed by anabolism (growth) while the muscle is at rest.  

How then can we design our training to optimize the application of stress to our muscles in a way that is consistent with our goals?

First let’s establish some training principles.  There are four points I will discuss in further detail below:

1. Progressive Overload – workouts need to get more difficult over time.
2. Training Specificity – exercises should be selected according to specific goals.
3. Plasticity and Reversibility – the muscle adapts in response to the degree and frequency of stimuli (exercise).
4. Inter-Individual Variability – workout programming requires a customized approach (e.g. body type differences between people).

Give a man a fish and you feed him for a day; teach him how to fish and you feed him for a lifetime.  As you learn the details that follow, you will be able to dramatically improve the efficacy of your approach to fitness, not just today but forever.

Training Principle 1: Progressive Overload.  o cause muscle adaptation, we must overload our muscles progressively.  That means your workouts need to get more challenging over time. There are five primary training variables you can use to present this overload stimulus to the body, causing the strongest adaptive response from the muscle:

1. Volume: how much total work are you doing? (Volume accounts for the number of exercises, reps, and sets you’re performing each workout, as well as the total amount of weight you’re lifting.)
2. Intensity: how much weight are you lifting for a given exercise and how close are you to your maximum effort?
3. Tempo/Cadence: how long or at what pace are you moving the weight?
4. Frequency: how often are you working out?
5. Mode: what type of workout are you doing? (For example: circuit training, crossfit, bodybuilding, powerlifting, etc.)

By increasing one or several of these variables from week to week we can encourage our muscles to repair and remodel themselves accordingly [4] [5] [6].   

Take Home:  We need to regularly present the body with a physical request that it cannot currently perform.  This will force the body to adapt in order to handle that stress in the future. Volume is the dominant factor and every variable that follows is a way of influencing the extent to which the body is experiencing more volume).  

Examples of Progressive Overload might include:

• Holding weight constant across exercises but increasing reps every two weeks
• Trying to perform the same number of sets and reps but using heavier weights
• Holding everything else constant but adding exercises to the total workout routine.

Training Principle 2: Specificity.  Our muscles respond differently depending on the type of stress applied by each exercise.  It’s important to match the type of exercise you’re doing with your specific fitness goals.

Specific exercises → specific acute effects → specific long-term adaptations.

So let’s go over some exercises designed for specific goals:

Goal: Defined Arms

Triceps generally account for 2/3 of your arm circumference, so we need to focus on this predominant muscle.  

Primary Exercises

• Dips (traditional and off bench)
• Close grip bench press
• Cable Triceps Extension   

Secondary Exercise

• Close Grip Push-ups

Goal: Developed Chest

An underdeveloped chest is often caused by overactive deltoids.  We combat this by pulling your shoulders back (pinching your shoulder blades) through the pressing movement.   

Primary Exercises

• Dumbbell (DB) Chest Press
• Incline DB Chest Press
• Decline Cable Fly

Secondary Exercises

• Push-ups
• DB Chest Fly

Goal: Increased Bench Press Strength

Lifting “heavy” is also a skill.  We should practice using heavy loads periodically.  

Primary Exercises

• Barbell Bench Press
• DB Chest Press

Secondary Exercises

• Incline Press
• Decline Press

Goal: Developed Glutes

This muscle controls hip extension and external rotation.

Primary Exercises

• Hip Thrust (use a Hip Circle/Band for added effect)
• Glute bridges

Secondary Exercises

• Squat (bend knees below parallel)
• Deadlifts

Training Principle 3: Plasticity / Reversibility.  While your body responds favorably to the stress of training, some adaptations are lost once overload has ceased, with some vanishing faster than others [7].  This is what the phrase “use it or lose it” was invented for.  As training volume or intensity decline, so do some of the improvements we made during the overload phase of our program.   But with the appropriate rate of progression in exercise volume and a sufficient recovery period between each training cycle, some of the gains made can be maintained.

Adequate rest is essential for muscles to fully adapt to the overload we’ve subjected them to, and it will also prepare them for the next workout [9].  Your ability to match performance form exercise bout to exercise bout is a good indicator of rest quality. For example, if you exercise the same muscle group twice in one week, during the second session those muscles should perform at the same level they did during the first workout.  Your required rest period is thought to be negatively correlated with your level of training, since highly trained individuals have been observed to recover faster.  If you’ve been hitting the gym for years you’ll likely need less time to recover, though it does differ from person to person.

Training Principle 4: Body Type Variation.   people respond differently to training stimuli, with one person seeing rapid gains while another must work harder and longer to make similar progress.   While this is largely due to genetics, you aren’t doomed just because it takes longer for you to see results. By leveraging the principles outlined above consistently and by committing to work hard, you’re just as likely to reach your goals as anyone else. Programming should be tailored to you, since no ONE way is the best way for everyone.

So, if we leverage these principles can we gain muscle while losing fat?

In some cases, people can actually experience muscle gain during periods of fat loss. Clearly, considering the case made thus far, this represents the ideal scenario for body recomposition.   This is often attributed to the training status of the subjects evaluated. Beginning weight lifters are among those well-positioned to make progress toward both goals simultaneously - since they experience such robust responses to the new stress of resistance training, for a time they can defy physiology.  

Even relatively experienced lifters can reasonably aspire to lose fat and gain muscle at the same time, accomplished by dramatic shifts in training. Variety is an important ingredient for other reasons, too, both psychological and physiological: it helps keep things fresh and also provides a much-needed shock to the system.  Don’t be afraid of waking up the morning after a major training switch, such as from powerlifting to CrossFit, feeling like you were hit by a truck. Embrace it.

What we’ve learned about weight training thus far:

• An intelligently designed weight loss plan prioritizes resistance training.  
• Workouts need to be specific to our goals (i.e. muscle groups you want to improve, endurance, etc.).  No one program fits all.  Adapt plans and training modalities to best reflect your goals and measure goal-specific progress periodically.
• Workouts need to progressively increase in intensity over time.
• Rest periods will depend on your level of training – the more experienced you are at weight lifting, the less time you’ll likely need to rest before exercising a given muscle group again.

What should my workouts look like and how long should they be?

The latest fitness studies tell us just how little stimulus our muscles need to enjoy significant growth.  Despite the ironman or weekend bodybuilder in your office bragging about spending two hours in the gym every day, this is simply excessive for general body recomposition goals.  

Enter circuit training, a way to structure workouts that lets us condense the most volume in the shortest period of time.  We do this by taking minimal rest periods (e.g. 30 seconds) and keeping repetitions high (i.e. 15 – 25).  Building our workouts this way offers a range of benefits:

• Sufficient stimulus to elicit anabolic response (muscle protein synthesis)
• Increases metabolic demand (results in decreased substrate/glycogen stores)
• Dramatically reduces workout time (workouts typically range from 25 – 45 minutes)

I’ve provided sample circuit training workouts at the end of the book, which can be tweaked to suit your specific fitness goals.

Why and when is cardio an important component to implement?

Since the aerobics movement of the 1980s with Jane Fonda in spandex and leg warmers, many of us have operated under the assumption cardiovascular exercise is most important for fat loss.  Even though you likely burn more fat than carbohydrate during aerobic exercise, it doesn’t mean you are having a superior effect on long-term body fat loss. As explained earlier in the chapter, the importance of maintaining muscle during periods of weight loss is critical to ongoing progress.  Excessive amounts of cardio can blunt your ability to grow or sustain muscle and in some cases it can actually lead to decreases in muscle mass. Clearly, you need to be cautious of the amount of cardiovascular exercise you’re doing particularly if it’s replacing resistance training.

Cardio is not all bad.  In fact, if it doesn’t sacrifice weight training entirely it can be quite beneficial.  Cardio benefits include:

• Cathartic release / stress reduction
• Opportunity to catch up on other things (e.g. podcasts or audiobooks)
• Cardiovascular health
• Increased use of predominantly fat for energy

Just don’t get carried away with that last point.  Although this type of exercise will burn predominantly fat, that’s largely meaningless in the context of your full day.  For instance, if you burn 500 calories during your 60 minutes on the elliptical, the majority of which may come from fat, you would quickly consume those calories and more in even the most fat-conscious of meals.

It’s always important to consider big-picture effects.  For example: changing your training style or intensity to burn more fat throughout the day – a process that continues even after you’ve finished your workout.  Metabolizing carbs during a workout is not the only relevant way resistance training contributes to body recomposition. Arguably more important is the resultant increase in the amount of fat your body will burn for fuel throughout the remainder of the day.

Take Home:

• The goal of weight loss should be replaced by one of “FAT LOSS.”
• For health and aesthetics, we want to minimize muscle loss during fat loss
• Resistance exercise is best for muscle maintenance and growth
• If operating under time constraints, use circuit training to achieve maximum effect in minimal time
• Incorporate cardio, providing it doesn’t distract from weight lifting efforts