“You may not think running can build big legs but it is certainly possible.”
So you’re a hardgainer trying to bulk up. You’re eating in a caloric surplus, you’re lifting weights, but should you, a hardgainer, do cardio? And if you do, how much and for how long?
Cardio (short for cardiorespiratory training) is integral for human health, as it has a plethora of amazing benefits to our bodies such as reduced blood pressure, reduced chronic pain, increased sleep quality, and more. But can it be detrimental to our weight gain journey?
In this article, we will visit the many questions of adding cardio to your bulking journey and find out whether it’s a good idea to do cardio if you’re trying to gain weight.
What happens to our bodies when we do cardio?
When we run or participate in any other aerobic exercise, we place a demand on our muscles. Our muscles and lungs suddenly require much more oxygen which is delivered by blood pumped from the heart.
The increased demand on our heart is the main reason our heart rate increases when we do an activity, having to pump a much higher volume of blood. The amount of blood pumped in one beat is referred to as the “stroke volume”. The heart rate and stroke volume together determine the output of blood by the heart per minute, also known as “cardiac output”.
Normal cardiac output for a healthy resting individual is approximately five to six litres per minute, depending on the individual’s size. This will increase to three to four times that amount during exercise even reaching an output as high as 30 litres per minute in some individuals.
If you’ve been reading our other articles at thesmartgainer.com, you’ll know that in order for a muscle to hypertrophy, it must be overloaded progressively over time.
The heart is a muscle too, it will grow if the environment demands so. The more cardio you do, subjecting your heart to high cardiac output, it will become stronger and thus more efficient, outputting more blood per contraction.
This means that an athlete’s heart has to pump less than the average person’s heart because it is stronger.
A normal resting heart rate for an adult is anywhere from 60-80 beats per minute. You can check yours right now by counting your heartbeats for fifteen seconds, and multiplying that number by four. An athlete’s heart rate can be as low as 30-40bpm. Impressive!
Furthermore, regular cardiovascular training also increases total lung capacity which in turn increases the amount of oxygen able to be exchanged within our blood.
Cardio places demand on the systems in our bodies when we do it, and very favorable adaptations occur over time.
The constrained energy model
Before we proceed, we have to talk about the constrained energy expenditure model.
This new take on energy expenditure has come to light in recent years largely due to Herman Pontzer, Ph.D. This research has reformed the way we understand our metabolism. Up until this research, the fitness industry adhered to something called the additive energy expenditure model. This is the theory that our bodies burn more calories based on the amount of physical activity we perform in a day. For example, a run on the treadmill will burn X amount of calories which would permit one to eat a donut presumably guilt-free that night.
What the constrained energy model has taught us is that our bodies adapt and allocate energy in response to the levels of physical activity we take part in. Our bodies, in a way, self-regulate in order to maintain total energy expenditure. This means that more exercise does not always lead to more calories burned and more weight loss.
With this theory in mind, studies are now showing that energy expenditure does increase when one increases the amount of exercise, but not by much and not for long. Regular and intense exercise does not correlate with a high energy expenditure as we thought before, since there is a plateau that occurs when a certain level of physical activity is reached.
Here lie the answers to our questions regarding cardio for a hardgainer. Since the constrained energy model is more accurate, it will be taken into account for the remainder of this article (and beyond, too).
Will it increase your metabolism?
When we exercise, our bodies use the glucose we have stored in our muscles. For our bodies to replenish those glucose storages, we use calories.
High-intensity exercise or strength training will use the most glucose, and thus spike your metabolism more than something like cardio. This is in part because cardio uses little glucose, preferring to burn fatty acids instead.
Doing cardio will increase your metabolism but not by much, and it’s not going to hinder your bulk.
How many calories does cardio burn?
First of all, every individual is different so the answer is going to be different for everyone. Primarily, size and weight are the determining factors but as we learned in a previous section, the constrained energy model has taught us that there is a plateau that occurs after a certain point.
A recent study found that untrained individuals who began an exercise regimen experienced an adaptation phase where more energy was burned. Once each subject became used to the routine and activity level, their energy expenditure stopped increasing.
From a hardgainers perspective, we want to know this data so we can accommodate by consuming extra calories to offset the calories lost through the cardio. However, it is near impossible to accurately predict the amount burned outside of a lab. At the end of the day, simply googling “How many calories does X minutes on the treadmill burn” will probably suffice. The constrained energy model found that individuals who are more active, actually do not burn many calories more than the average human. So, if you’ve considered skipping cardio to save those calories, also consider the benefits of cardio, even if it’s just a warm-up to weight lifting.
Should skinny guys do cardio?
Yes, everyone should do cardio, even skinny guys.
So now that we know that cardio doesn’t place a high energy demand on the body relevant to our previous understanding, will skinny guys benefit from it?
At the beginning of this article, we talked about the effects of cardio on the body such as the development of the heart muscle and increased lung capacity. When our heart is stronger our blood flows better and this has many fantastic benefits.
According to the Centers for Disease Control and Prevention, the number one cause of death in the U.S. is heart disease. Many scientists and organizations including the CDC have published numerous scientific reports reinforcing the evidence that more active or fit individuals have a far less tendency to develop cardiovascular heart disease than those who are sedentary. Furthermore, if a healthy individual does develop CHD, it is always at a later age and less severe.
In an article published by Jonathan Myers in Circulation, he states that “As many as 250 000 deaths per year in the United States are attributable to a lack of regular physical activity”. Let that sink in.
Of course, there are hundreds of diseases and health risks related to being sedentary but what about the physical benefits of cardio and regular exercise?
Improvement of muscular function and strength means that you’ll go about your daily life with less fatigue. You’ll also experience improved sleep, improved mental health, and a better immune system.
Does cardio add muscle to your legs?
You may not think running can build big legs but it is certainly possible. The muscles in our bodies are composed of two muscle fibre types: Slow-twitch, and fast-twitch.
If you want to build big legs, you’ll probably (hopefully!) start by squatting. While this is a sure way to get started, squats are going to give preference to fast-twitch muscle fibres when it comes to hypertrophy. Slow-twitch fibres are targeted better through endurance training like long-distance running. Ideally, an individual would do both leg training and cardio if they wanted to maximize leg gains, but the squats are going to be the largest contributing factor.
Now, if you are an experienced lifter who has already added considerable size to your legs, you may not see amazing results if you begin running. But if you’re lifting weights once or twice a week, running is going to bring noticeable gains.
With all of the benefits that cardio has, with very little cost, why not try it? It would be worth it even if you are purely trying to build muscle because of the slow-twitch muscle fibre activation.
Will cardio reduce overall muscle?
There is no evidence suggesting that cardio would lead to muscle atrophy (losing muscle) in a healthy individual who has a well-balanced diet. When a muscle wastes away, it is typically from a lack of physical activity. Many diseases or injuries can lead to muscle atrophy and it is usually when the individual’s mobility is compromised.
However, muscle can be burned through cardio under two plausible circumstances. The first is a lack of nutrition. If your body is suffering from a severe lack of fatty acids and calories, it can resort to burning muscle. The second is if the individual is doing too much cardio. Don’t worry- this is an extreme amount of cardio and it is highly unlikely that you would just stumble into this level of activity. The same principle applies, as the body’s demands would be higher than the nutrition of one’s diet could supply.
Again, from a hardgainers perspective, it is going to be impossible to lose any muscle from cardio as long as you’re eating food. And if you’re trying to gain weight, you should be eating a lot of food.
Is cardio better before or after lifting?
This is going to be dependent on your workout routine for that given day, as well as your personal preference. Warming up before a workout is always necessary. Some people may run on the treadmill for ten to fifteen minutes as a warm-up and that’s perfectly fine.
If your cardio session is intense in any way (it probably should be!) then it may be beneficial to save it for after your workout as it will use up a lot of energy and you’ll run the risk of fatiguing your muscles before actually lifting weights.
If you have a big leg day planned, you may want to ease up on the cardio the day prior or at least before the workout.
It is all preference. The benefits and risks we’re referring to in this section are marginal. I would highly recommend that you do cardio when you prefer it the most.
Should you do cardio every day?
The only risk worth considering here is fatigue. Many individuals choose to run every single day and that is perfectly ok. If the only physical activity you did was jog, then physical fatigue would likely never catch up to you. However, there are many factors to consider such as stress, sleep, diet, and potential injuries.
The term “burning out” is when fatigue builds up and you begin to feel exhausted from too much of something- in this case, training. Learning to allocate and balance your training schedule can be very helpful to avoid burning out. And learning to take a day off when you need it is far underrated and underperformed.
So should you do cardio every day? If you enjoy it and if it’s possible, yes.
Summary
Previously we believed that more cardio meant a higher energy expenditure. For someone looking to bulk up and add mass, this was a red flag. But we now understand that the body is quite advanced at dialing back the calories burned from exercise. And it makes sense! Cardio is so beneficial to our bodies and health, so why would we not evolve to be efficient at it?
Skinny guys, don’t worry about cardio hurting your gains. The health improvement from a regular aerobic activity is going to help build muscle in the long run. You’ll even experience some leg gains and no, you won’t burn up any muscle anywhere else. Not to mention, you’ll live longer. (That means more workouts!)
Do as much cardio as you can, but pay close attention to what your body is telling you. If you overload yourself with too much exercise, you’re putting yourself at risk for injury and nobody wants that.
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