Fitness Myth #3: Doing a ton of cardio will help you get ripped
Stop me if you’ve heard this before: doing a ton of cardio will help you get ripped. While this might seem true at face value, it may not give you the results you are looking for. Cardio may help you get into a calorie deficit, and therefore lose fat, but it will not help if you are not paying attention to your diet, working to increase your lean body mass, or both. Cardio is simply a tool in the weightloss toolbox, not an overall solution.
If you are one of the people at the gym pounding away for hours per week on the treadmill, stairmaster or stationary bike, and more recently, walking running and jogging to keep fit during the circuit breaker, you may not be getting the results you want. Keep reading.
Now before you think I’m not into cardio and don’t use it as part of my exercise prescriptions, I do. Cardio has a great many benefits to your health such as increasing the efficiency of your heart, lowering blood pressure, building endurance, burning some extra calories and many more. What I am stating is that cardio alone is not enough. It is best employed as a supplemental training to a proper weight lifting program.
So why isn’t cardio enough?
There are 3 main reasons:
Bioenergetics
Muscle Physiology
Exercise Variable Manipulation
Let’s look at these in a tiny bit more detail, although each topic really does deserve its own post.
Bioenergetics is simply the science of how our body uses the energy we provide it by what we eat. The 3 main macronutrients of fat, carbohydrate and protein get used by our bodies differently depending on the type of exercise we do, aka cardio versus resistance training. Your body has 3 energy pathways, Phosphagen/Creatine, Glycolysis or Glycolytic pathway, and Oxidative Phosphorylation pathway. Each pathway has a prefered macronutrient, type of activity, and time to exhaustion. To make this short, most cardio based activities (such as jogging) rely on the oxidative metabolism, which prefers dietary fat, blood glucose, metabolites caused by glycolysis and will even consume amino acids if nothing else is available. While it may seem good that fat is the main energy substrate, it doesn’t necessarily refer to body fat. Unless you are in a calorie deficit.
Muscle Physiology is the makeup and distribution of muscle fiber types in your body. Not all muscle fibers in your body are created equal. We have 3 main types of skeletal muscle that are used during exercise. They are differentiated by their size, power, strength and endurance potential, and energy pathways used during contraction. The muscle that is recruited during most cardio activities are Type 1, slow twitch or slow oxidative fibers. These are small diameter muscle fibers with limited hypertrophy potential. They rely on oxidative phosphorylation for energy and are focused on endurance, with very limited strength and power potential.
Exercise Variable Manipulation refers to the types of variables we can manipulate, such as load, sets, repetitions, intensity, duration, frequency, and more. When it comes to traditional cardio based activities, the main variables we can manipulate are frequency, duration and intensity. Meaning we can perform the activity more times per week, do it for a longer period of time, or increase the speed at which the activity is performed.
Now if that isn’t confusing enough, I don’t know what is. Just to summarise, cardio, as commonly referred to, has many different modalities. Let’s look at a few types of “cardio”:
LISS or Low Intensity Steady State Training is getting your intensity, best determined by heart rate, to a certain level and then keeping it there for a period of time, say 30 minutes. This is the infamous “fat-burning zone” or “cardio zone”, one of the biggest misunderstood aspects of aerobic training. While LISS can be helpful for building an endurance baseline, and is definitely part of active recovery, it doesn’t really provide an effective overload stimulus to drive a range of adaptations. An example would be walking or a jog. This is the most common type of cardio that people do. It is better, however, than sitting on the sofa.
HIIT or High Intensity Interval Training involves training at a very high intensity, as best determined by heart rate, for a period of time (interval) and then lowering the intensity to recover and then increasing again. Basically you would go all out for say 30 seconds, then spend one minute resting, then another interval at full intensity. Rinse and repeat. An example is airbike intervals, where you pedal all out for 30 seconds or 1 minute followed by 1 minute of slow pedalling to recover. All forms of HIIT have been shown to increase calorie burn over LISS, and engage all 3 metabolic pathways, in addition to recruiting more muscle types.
Conditioning is a term we use in athletic training to denote training modalities that improve an aspect of athletic performance in regards to a specific requirement of the sport. In other words, we program conditioning sessions to mimic the metabolic demands of the sport that the athlete partakes in. We could use both HIIT or LISS or other types of conditioning such as sled pushes, HIRT (High Intensity Resistance Training), and many others to increase performance.
So just summarize the above, Cardio alone is not enough to drive all favourable physiological adaptations. While straight “cardio” will increase your cardiovascular fitness meaning the efficiency of your heart and lungs to supply your body with oxygenated blood, it will not increase your muscle size, strength, power, and will have limited effects on your fat-loss unless you can sustain a favourable calorie deficit. Steady state cardio in particular uses only 1 of 3 energy systems and 1 of 3 muscle types. HIIT cardio depending on the modality does provide more energy system use and muscle fiber use, is more time economical and can use basic resistance training.
A complete training program will balance strength training with conditioning to provide a complete improvement. Just like we do at our gym.