Posted February 16, 2020

Why You Should Do Cardio

I’ve long championed doing some form of aerobic or anaerobic conditioning on a regular basis for everyone. Yesterday I put up a post in Facebook and Instagram outlining a few of the major benefits that you can get from it:

So today I wanted to tackle a 2-part phase on this topic. Part 1 is the reasons why you should do cardio, and part 2 is the myths about cardio that you may hear, and ways to overcome them.

Part 1: Reasons Why Cardio is Good For You

As a personal trainer, strength coach, exercise physiologist, and whatever else I may want to call myself (note, if I ever call myself an influencer or worse, thought leader, feel free to punch me in the face, either digitally or in person), I work with a wide variety of clients. Some are just getting started with exercise for the first time, some are seasoned lifters looking to increase their strength, others competitive athletes looking to compete in world championships, Olympics or Paralympic games. Many are coming off some form of an injury or have a medical condition that affects how they work out, so it’s a mixed bag to be sure.

The cool thing is that in every one of these clients, some volume of aerobic or anaerobic work can help them reach their goals.

For beginners, cardio can be a less intimidating, less technical, and can make the individual less sore than doing structured weight training. This is not to say that weights don’t have their purpose, but I’m just outlining some reasons why cardio can be beneficial. Ease of use in a population that’s likely already overwhelmed just stepping into the gym is a big win.

Cardio also affects blood vessel pliability, which makes their cardiovascular system more adaptable to changing stressors and loads, something that’s very important when they start increasing the intensity of their workouts or adding loading to their weight training. An increased delivery of oxygen through their system and removal of waste products helps reduce feelings of soreness following the workouts, which can help them want to come back again tomorrow, so in terms of accountability and consistency, these are BIG wins for involving cardio. There’s also the whole effect on blood sugar, blood pressure, triglycerides, ejection fraction, O2 exchange, yadda yadda yadda.

This can also be beneficial for strength athletes who consider anything above 4 reps as cardio too. Some low intensity steady state work (LISS) can help with oxygen delivery, allowing the athlete to recover from intense workouts more effectively. The removal of waste products can help expedite the warm up process, plus the rhythmic contract/relax cycles can do wonders for tendon pliability. You know, those things that hold your muscles to your bones and get cranky AF as your lifting volume goes up? Those. Take care of them.

What about calorie burning? Contrary to popular belief by many in the fitness industry, yes, adding cardio in can help you burn more calories. And in instances where your diet is either in a caloric deficit or homeostatic, adding in 200-500 calories a day of exercise related caloric expenditure can actually help you lose weight. I know, it’s shocking, but stay with me here:

More exercise………….. helps with weight loss.

It’s hard to believe that this is a controversial stance to take, but it’s 2020, and here we are.

For 99% of the people who need to hear this, cardio is not going to be a bad thing for you, kill your gainz, or cause spontaneous marathon running. It’s okay to think 20-40 minutes of some daily zone 3 or 4 intervals will be beneficial to you, and that you can actually do it without sacrificing hard earned muscle tissue.

I will include a caveat. Let’s say you’re a high performing strength athlete, peaking bodybuilder during a bulk phase, or someone who has a medical condition like peripheral vascular resistance. In those instances, sure, cardio on top of your regular training may not be beneficial, especially if you’re in-season and looking to compete soon for strength athletes, or if you’re off-season and trying to cram as many calories into your muscle-hole as possible and to make sure you have every growth stimulus possible to get absolutely “Jacked” (or for the women looking to add slabs of meat to their build, “Jilled”).


Because those very small subsets of the population get a pass doesn’t mean Gary from accounting who sits 80 hours a week and hasn’t had his heart rate over 120 beats per minute since he played football with Al Bundy at Polk High needs to skip cardio to protect his muscle mass.

Context matters a lot when it comes to recommendations and also to arguments against something, which is where part 2 of this piece comes in.


Part 2: Myth Busting Claims Against Doing Cardio

Let’s start with the obvious ones first. Cardio will kill your gains and make your muscles shrivel up to nothing but a textbook sarcopenia and terrible Tinder profile pic, right? Also, it won’t help you lose weight and will likely make you gain fat.

Wait, how can it simultaneously make you lose muscle and gain fat, while actively exercising? Shouldn’t it be one or the other? How can I be storing energy in fat cells while also breaking up muscle tissue that’s trying to use that energy?

Seriously, get your stories straight.

First, how much cardio are you doing that you’re seeing a loss of muscle mass? If Gary from above is coming in to get yoked for his board meeting to discuss balance sheets with sleeveless dress shirts, are his pipes shrivelling up from getting in 30 minutes on the elliptical 4 times a week? If that’s the case, we need to discuss actually eating food, likely some protein, and get in a set of curls once in a while.

Looking at the very high end of endurance events, Zouhal et al studied participants in the 6 day run across the Moroccan desert and showed that there was a significant decrease in fat free mass on day 3 and 6 of the run (-3.5% and -5.0%). So if you’re packing about 80kg of total body mass, you would have lost about 4kg of fat free mass, which includes everything that’s not fat, like muscle, water, bone, etc. This is also running ACROSS THE MOROCCAN DESERT IN 6 DAYS. Odds are you’d lose a ton of water weight that would factor into these calculations.

That being said, without pushing incredibly extreme cardio, you could see a similar decrease in fat free mass just by doing a keto diet. Urbain et al showed a 6 week keto diet averaged about 0-4 kg of total weight loss, half of that of that coming from fat free mass, which could come from the water loss from not storing as many carbohydrates in muscle and liver tissue. That’s relatively equal to the amount of fat free mass lost running across the freakin Moroccan desert in well trained endurance athletes.

Now I’d imagine most people out there are NOT RUNNING ACROSS THE MOROCCAN DESERT, and thus don’t have to worry about this amount of fat free mass loss from their inclined walk on the treadmill while they watch an episode of Letterkenny on their phone.

Consider skipping cardio as being as egregious as skipping leg day.

Next up, let’s talk about body type and shapes. A common discussion against cardio is that if you do it, you’ll look like a marathon runner versus a sprinter.


Now, something to know about this comparison: It makes literally no sense.

Are you telling me that 20 minutes of cardio each day will make me resemble a champion 10,000 meter runner? Will doing a few sets of squats and deadlifts on a 5-3-1 make me into a muscle-smashed sprinter capable of running a sub-10 second 100? I’d be alright with either or both of those results if it was easy enough to achieve as that.

If my marathon runners, who in the lead up to competition train 10-20 hours a week depending on their stage of training and tolerance of volume, don’t see any specific decreases in fat free mass but may actually INCREASE based on increased glycogen and water storage, my guess is you won’t shrivel away and atrophy with 3 hours of work a week, assuming you’re eating enough protein and getting in a few weight training workouts each week to stimulate that muscle tissue growth. Likewise, walking past the weight room and doing a curl won’t turn a runner into the sprinter pictured above.

The results these people achieved comes down to a couple of key features: genetic body type, survivorship bias (good endurance runners keep running endurance events, whereas explosive runners gravitate to sprinting), training history and focus (my guess is the sprinter spends a fair amount of time in a weight room as well as on a track), and diet (the sprinter likely crushes about double the protein as the distance runner, maybe more, I don’t know).

Does this mean the recreational lifter who’s never competed and only posts progress videos to Instagram for his 15 followers has to avoid cardio because he’s scared of “losing his gains”? No. No he does not.

Using extreme examples to justify the average does nothing but muddy the waters and loses all context about what you’re talking about. The worlds greatest extreme sport athletes’ workout and nutrition habits have literally zero bearing on how you will respond to exercise. Once you get your frequency up to 12 or more workouts a week, we can discuss whether to skip your zone 2 work, but until then, just do it.


Now let’s get into the fun stuff: Objections


“It’s Boring”

So is brushing my teeth, being stuck in traffic, cleaning my stove, and paying my taxes. What’s your point?

Exercise has no obligation to entertain you while you do it.

That being said, I get it. If it’s not something we consider fun, exercise becomes less palatable. This can be a big reason to try different types of exercise to see what ones strike a chord. You don’t have to just walk on a treadmill or ride a spin bike for cardio benefits. Take a dance class, roll in jiu jitsu, go for a walk/jog in a park, play a sport, what ever you want that will get you a higher heart rate for a few minutes at a shot. The more you enjoy it, the more likely you are to do it regularly.

Now, it may not be prudent to come home from a long day at work, manage kids and then go out to a dance class. For those times, consider it “punching the clock” and just do whatever kind of activity you have access to, get it done, and move on. In other words, treat it like a kid treats brussel sprouts. No dessert until you clear your plate.


“It Takes Too Long”

Seriously, what else did you have going on? Could you do some form of cardio while watching any of the television you currently watch? If you read, could you read while pedalling a bike or walking on a treadmill? Could you bike to work or power walk to the office? The cool thing about a lot of forms of cardio is you can multitask with a bunch of other stuff you’d likely be doing anyway so it’s not about taking up more time, just about shoe-horning it into your existing time-sucking activities.


“I’d Rather Lift Weights”

Good for you. I’d rather lift weights and be able to walk up a gentle incline without gasping for air, but you do you.

I’m all for having a main focus in any training program. If yours is weight training, give ‘er buddy. Just add cardio in around the edges so you can get that exercise benefit too. Don’t skip the cake because the icing is your favourite part. Eat them both.

Man, I’m a one-liner quote machine on this piece.

In conclusion, cardio will not likely make you lose gains unless you do a metric shit-ton of it and are not eating enough protein to feed your muscles, could help weight loss when combine with a caloric deficit, and will likely help every facet of physical health and performance when actually performed somewhat regularly, or at the very least not interfere with other elements of training you might be doing unless you’re in the top 1% of 1% of lifters out there. Which you’re likely not, so don’t worry about it. Just get sweaty and gross and then do it again tomorrow.