How And Why To Do Cardio

Feeling depressed? Go run in the forest with a dog! I promise you'll feel better.

*Adapted from my upcoming ebook: How to Feel Good

I like to think of cardio days as “Heart Day”, just like gym bros allot certain days of the work as Chest Day or Leg Day, Heart Day is equally if not more important.

I mean, it’s in the name, right? Cardio is short for cardiovascular, as in cardiovascular health. You know, the thing that you need to keep up with if you want to not die from a heart attack? Which is the number one cause of death in the US (and most places). And just like strength training, there's about a million reasons to do it that aren’t just ‘lose weight’, even if that is one of them. Here’s a few others:

• Improves cardiovascular health

• Lowers blood pressure

• Helps regulate blood sugar levels

• Reduces chronic pain

• Helps you sleep better

• Strengthens the immune system

• Improves cognitive health

• Improves mood and feels good!

Let’s talk about that last one. Improves mood and feels good. You might be thinking to yourself, “I totally disagree, I hate doing cardio!” but I’m willing to guess that there’s at least one occasion you can think of where doing cardio was fun. Maybe you were running around on the playground as a kid, hiking in a national park, riding bikes with friends, playing tennis, moshing in a mosh pit! All of those are cardio and none of them involve a treadmill or elliptical.

Ever heard of the ‘runner’s high’? I’m sure you have. It’s a sense of euphoria when running. Ask any runner about it. Running, straight up, feels amazing. My drug of choice is trail running. I feel absolutely wonderful when I’m trail running. My brain becomes more neuroplastic and suddenly, everything is better. Music is better and I want to dance. I feel more playful and I start to bounce off rocks and logs rather than avoiding them. I feel full of potential, like I could literally do anything, and I start to have delusions of grandeur. Maybe I’ll sail around the world, maybe I’ll run to Patagonia! But they aren’t delusions, I’m just noticing the real potential available to me that I’m normally blind to. I get emotional, it feels like a release. I work out most of my problems in life on my runs. But I do more than that, I write lyrics, I sing songs, I come up with ideas for art and adventure. I have all of my best ideas while I’m running through the forest. The world is brighter and more beautiful and I am more capable. That’s what running does for me.

And that’s what cardio can do for you too.

So what exactly is “cardio”, well like I said earlier, cardio is short for cardiovascular, or in this case, cardiovascular exercise. Cardiovascular exercise is any activity that increases your heart rate and breathing for a sustained period of time. Strength training might very acutely and temporarily increase your heart rate, but it doesn’t sustain it nor does it raise your heart rate much.

Cardio can be walking, jogging, biking, swimming, rowing, hiking, martial arts, skiing, jumping rope, cycling class, canoeing or kayaking, snowshoeing, HIIT (high intensity interval training), sprinting, even dancing! Anything that raises your heart rate for a sustained period of time is cardio. Most sports require good cardiovascular fitness, which is why ‘conditioning’ is half of ‘Strength & Conditioning’.

So what should you do for cardio? Easy, whatever you want to and whatever you will. Don’t try to do the cardio you won’t do. If you don’t want to be a runner and you hate running then don’t force yourself to run (unless, maybe, you like to force yourself to do things you hate). If you do like to swim and you have access to a pool then by all means, swim! Do what you can to reduce friction between you and swimming. Keep your swimming gear in a bag in your car when you go to work. Join a gym with a pool that’s on your way home from work. Buy swimming shorts that you like. Reduce friction between you and the thing you want to do.

If you don’t know what you want to do then try different things. Queue up your favorite podcast and hit the elliptical, go on a hike, try a zumba class, join a jujitsu gym. These are all cardio.

Two big differences between different types of cardio that I want to talk about are Intensity and Impact.

Low intensity exercise is more sustainable, and well, less intense. I think you can easily draw this distinction for yourself but walking is low intensity whereas sprinting is high intensity. High intensity work is unsustainable and much more fatiguing. I recommend doing mostly low intensity cardio with a workout or two a week being more intense. It doesn’t have to be sprinting, which is about as maximally fatiguing as it gets, but it can be faster intervals, getting your heart rate up and out of Zone 1 and Zone 2 (hold on, we’ll talk about zones in a moment). Different levels of intensity stimulate different adaptations, and if you’re asking me, you want all the adaptations. So try to get your heart rate up as high as you can tolerate or is safe for you, even if just once a week.

Low impact exercise is… again, you guessed it, less impactful. So just less jarring on your joints/muscles/bones. Is that a good thing? It’s neither good nor bad, it’s just different than higher impact exercise. Low impact is sustainable and less likely to lead to injury or overtraining and requires less recovery. High impact is less sustainable but leads to more tissue adaptations in the joints, muscles, and bones that makes your body more resilient and less likely to injure. Remember, you have to stress yourself and push yourself to discomfort or even failure in order to adapt. So you see, neither is better than the other, they both have their place. If you’re asking me, then you want most of your training to be low (or lower) impact, and some of your training to be high (or higher) impact. Sprinting is a great high impact exercise that leads to amazing adaptations, but don’t overdo it. Even one 40 meter sprint a week is a great place to start.

Let’s say someone comes up to me and says, “Colton, I want to build the most robust cardiovascular fitness possible. I’m a healthy 35 year old man, but I’m untrained. Where do I start?”

I’d say, “Well hypothetical healthy but untrained individual, you just start running 3 days a week for however long you can stand. The cool part about being untrained is that you can start anywhere and it will be beneficial.” 

…which isn’t what they want to hear so then I’d hand them this:

Monday: Zone 2-3 30 minutes

Tuesday: ‘Tempo’ run, 10 minute Z2 warm up, 4 minutes at a much faster pace, then 4 minutes of a slower pace than your warm up, 4 minutes at a much faster pace, then a 4 minute pace equal to your warm up to cooldown.

Wednesday: Rest

Thursday: Long Easy Zone 2 (or Zone 1 for breaks, return to Zone 2 as soon as possible) for 60 minutes

Friday: Rest

Saturday: Sprinting, 10 minute Zone 2 warm up, sprint specific warm up drills, 4x40 meter dash 90% effort

Sunday: Rest

Why this program? Because it gets them doing work in every zone. Oh yeah, let’s come back to zones. Here’s a description of each ‘zone’ in my own words:

• Zone 1. Not sedentary but not vigorously active. Walking around, light gardening, no noticeable fatigue or faster breathing. Burns mostly fat instead of carbohydrates or creatine reserves. Time spent here is 50-60% of your maximum heart rate. No recovery required.

• Zone 2. Noticeably harder, still able to talk but might be less comfortable. Burns mostly fat but also burns some carbs. Time spent here builds the aerobic base, increases mitochondria density, and increases capillary density. The powerhouse of the cell, as you all know. 60-70% of your maximum heart rate. Some recovery required, normally less than a day unless it was a long workout.

• Zone 3. Moderately hard. Talking is now hard but doable, breathing has become much faster. Mostly burning carbohydrates but still burning fat. Improves aerobic fitness and endurance. Time spent here will make you faster. Also increase mitochondria density and efficiency. 70-80% of your maximum heart rate. A day or two of recovery required, especially if it was a hard tempo workout.

• Zone 4. Very hard work. Talking is almost impossible. Heart rate and breathing are very rapid. Time spent here will increase your lactate threshold, VO2 max, and mitochondrial efficiency. You’re burning almost all carbs and you can’t stay here long. 80-90% of your maximum heart rate. You’ll almost definitely need to take the next day off.

• Zone 5. All out effort. You can’t talk, heart rate is about as high as it can reasonably go. This pace can only be maintained for a very short period of time. Maximally increases VO2 Max, builds hella muscle, and improves mitochondrial efficiency under high stress. Will dramatically reduce leg injury incidence chances in sport, some call this the “speed vaccine”. 90-100% of your maximum heart rate. You absolutely will have to take a rest day tomorrow unless you’re very trained.

Remember, this is what I consider to be optimal, but optimizing is for the birds, just get out there and get your heart rate up for a few hours a week.