What exactly is cardio? Do we need to do cardio? Inside we’ll take a look at what cardio is, some of the best reasons we should do it, and how to get started.
What Is Cardio?
Generating ATP Energy
Our body generates and then uses ATP (adenosine triphosphate) for energy. This energy is the direct currency that we spend that allows us to breathe, lift things, move, etc.
There are two ways our bodies generate this energy.
- One way is to make energy without oxygen (anaerobic)
- The other way energy to make it with oxygen (aerobic).
Our bodies usually make this ATP energy anaerobically. While anaerobic produces greater force, it can’t generate as much energy as aerobic, and after you use it, it turns into lactic acid (the burning feeling when you start doing higher-rep work.) (study). But if you’re doing a lot of exercises, sometimes we burn out of the stored (and slower generating) anaerobic energy in a few minutes, so our body starts to blend in more aerobic work.
Both anaerobic and aerobic exercise work out the cardiovascular system but in different ways. So if one of your goals is energy, health, and performance, it’d be good to eventually build up the ability to include both types in your life.
But in general, any exercise that is explosive in nature, like lifting weights, is anaerobic and not “cardio.”
This is because your most explosive action is 6x more powerful than the maximum amount of energy aerobics can provide. So, any exercise done with maxed-out effort under 6 seconds is anaerobic. Then, exercises from 20 seconds–to 4 minutes with a high intensity are a mix of anaerobic and aerobic.
Then, endurance exercises that aren’t explosive are generally aerobic or “cardio.”
But the researchers said that any time you use intensity, that’d be the anaerobic system gradually stepping in. So if someone were running a track race and jogged at a low intensity for 10 minutes, that’d be aerobic. And then, as they came upon the final metres and started to run hard, it’d open up the anaerobic pathways for the boost of power.
So if we’re moving for a long time with a low enough intensity, our body needs more oxygen to keep moving, so we start breathing a little harder, and our heart starts to work harder to pump the blood with the oxygen to where it needs to be. This is how aerobic training plays its part in strengthening the heart.
For example, when you keep your heart rate up as you exercise, like swimming or walking briskly outside for 30 minutes, that will require lots of oxygen to generate continuous energy, meaning it’ll be an aerobic exercise and work out your heart.
What About HIIT (High-Intensity Interval Training) As Cardio?
High-intensity interval training is when you briefly push yourself and then take a short rest. For example, you might be on a stationary bike and do 30 seconds of hard pedalling with high resistance. Then, spend 2 minutes recovering. Do that 4–6 times, and you’re done exercising in under 15 minutes. HIIT trains both the anaerobic and the aerobic systems.
Most people use cardio to build their fitness, but some people use it specifically for fat-loss. How does HIIT do for fat-loss? In this 2017 meta-analysis looking at 28 studies comparing HIIT (high intensity) and LISS (low intensity like regular cardio), it found there really was no difference. So, some studies said HIIT was better for fat-loss, some studies said LISS was better, and some studies said they were both in the middle. (This is why we can’t just take one study and claim the answer is solved, we need a meta-analysis for more clarity).
Then in February 2019, a new meta-analysis came out looking at 41 studies comparing HIIT and moderately intense continuous cardio. The researchers said that the results were similar, but that people lost a bit more fat with HIIT (meta-analysis).
So a lot of people do HIIT because it’s more time efficient and also because it may be better at improving VO2 max, your maximum oxygen uptake (study). That’s a great reason to do HIIT.
But high intensity is high stress. That means that even though it takes less time to do, it’s still really tough and so you’ll need to recover from that.
We find people do better when they build a good cardio base first, through walking, and low stress cardio and working on eating a better diet.
Brisk Walking Is A Great First Step For Cardio
How long and how far can you walk at a brisk pace? Focus on being able to walk for a long period and a fast pace before moving onto LISS or HIIT training.
Once you’ve got a good cardio base, when it comes down to it—both LISS and HIIT are excellent ways to get leaner. So, personal preference starts to matter more. For example, my business partner Shane likes to do low-intensity cardio for an hour while listening to a podcast. He prefers to do something more leisurely and enjoyable and doesn’t mind spending the time since he can also be learning at the same time. But for me, I’d rather do the intense but quick HIIT sessions to save time. The fact that HIIT could be better at improving VO2 max, and could be a little bit better at burning fat is a nice bonus.
Top 5 Reasons Why We Should Do Cardio
Would you rather watch instead of read? Here’s the Youtube video:
1. Cardio keeps you looking and feeling young
In a study published in January 2019, researchers found that cardio (steady state as brisk walking and intense interval training) helped to keep cells “young.” But oddly, those in the resistance training group didn’t experience these benefits. Everyone became more fit in terms of cardiovascular health, but the weightlifters didn’t get the same cellular improvements (telomeres lengthening). According to an interview with the NYT, the researchers said that even though lifting weights is strenuous, the pulse rate of the heart was overall much lower, meaning less blood flow and less response from blood vessels. They said that even if you’re middle-aged, you can still help to keep your cells younger through cardio. (NYT article)
I am not saying that resistance training, like lifting weights, doesn’t help fight off aging. It just helps in a different way—mainly through fighting off sarcopenia, which is where you slowly lose muscle mass as you age. (Some researchers think you can delay sarcopenia with consistent weightlifting up until your mid-60s. And even after that, lifting still helps to radically slow down the problem.)
So, if you want to be optimally healthy, fit, and strong, you’ll want to do both cardio and lifting weights, as they work collectively.
2. Doing cardio improves your brain
In this study, just a 10-minute stationary bike ride boosted cognitive performance by 14%.
And in this study, it gave evidence that cardio could help with learning better and long term memory.
But there’s a whole host of studies slowly shedding light on cardio and the brain (study, study, study)
Dr John J. Ratey, a clinical professor of psychiatry at Harvard Medical School who’s published over 60 peer-reviewed articles and 11 books, wrote a book called Spark, where he explains the research of the massive range of benefits that cardio has on better learning and memory, expanded creativity, and improving the way you think (among other benefits). The short answer is that if you want to learn and think better, do some cardio, perhaps even in the morning before you start your day. (Here’s a 7-minute recap of the book on Youtube.)
3. Doing cardio helps to crush anxiety, depression, & pain
Far from just slowing the process of aging, cardio can also help fix a ton of other problems when it comes to overall health.
In this study, doing as little as one hour a week of cardio (light walking or swimming) was enough to ward off depression (study) and many studies have shown similar results (study, study). In these studies, cardio helped to squash anxiety (study, study, article).
And when we face the facts, cardiovascular disease is the number one killer of men and women in the US (article). The crazy thing, is researchers say this is largely preventable through exercising and staying lean—both things cardio can help with. Cardio also helps to fight off diabetes and certain cancers while helping you stay lean (review). And it seems like cardio could even help fight off dementia. (review)
4. Cardio might help to fight against hair loss
Hair loss is complicated, and it seems to be related to our genes. But, that said, losing your hair and graying hair is associated with early heart disease (study) and future prostate cancer (study, study). The crazy thing is that if you’re balding and graying, that’s an even bigger predictor of heart disease than being obese. Now, that doesn’t mean that bad cardio health is causing your hair loss, we don’t know that, but it’s possible it plays a role because our cardio helps to get blood and oxygen around our body.
In a 1996 study, researchers found that places where men are balding have 60% less oxygen compared to areas on the head with hair (study). A derma roller increases blood flow to the head, a head massage increases blood flow, and as we saw earlier in this article, people are putting minoxidil and caffeine on their head for increasing blood flow. (study)
It looks like stress may even play a role in hair loss, but it’s too early to tell for sure (study on mice). But lowering your stress is never a bad idea, and we know that doing cardio will help.
Calcification of our body might play a role in hair loss. The calcification on the head would choke out blood flow, and this could be why hair loss is related to heart disease. Calcification of plaque in the arteries is heart disease. (Harvard Health)
How can we lower our blood levels of calcium? High calcium levels and low vitamin D levels in the blood are linked. From this journal:
“The major function of vitamin D is to maintain calcium homeostasis. It accomplishes this by increasing the efficiency of the intestine to absorb dietary calcium.”
But now we’re discovering that it might not be the actual vitamin D itself (something we could supplement with) that helps, but the entire process of sunlight exposure.
- UVB hits our skin
- 7-dehydrocholesterol has its chemical bond broken by sunlight
- That converts 7-dehydrocholesterol into vitamin D.
- That process kickstarts many other processes, including helping us have proper calcium levels. (study, article)
So, have your brisk walk outside in the sun to boost your cardio. And if you’re in a high-latitude country, do it at noon when the UVB levels are highest. Your hair and heart will thank you.
5. Cardio may help men fight off erectile dysfunction
There’s more evidence that erectile dysfunction is now affecting men under 40 and affecting up to 30% of them (study). Why are so many men running into this issue? ED has many reasons (some of them being depression and anxiety, which cardio can help with), but for many men, it comes down to physical health.
According to this 2018 review (study), erectile dysfunction is related to being physically inactive, having hypertension, being overweight, and bad cardiovascular health. Basically, take ED as a warning sign that you’ve got bad cardio health.
The researchers wrote that based on the evidence, erectile dysfunction due to physical health could be fixed by doing 40 minutes of moderate to intense cardio four times a week.
How to get started with cardio
Hold up—do you lift weights?
To be clear, if you aren’t exercising at all right now, you should probably start with lifting weights rather than cardio. The first reason is because weight training is better for helping you burn fat and become muscular.
The second reason is that lifting weights will also work out your cardiovascular system in a *unique* way. In this 2019 study, people who did both resistance training and cardio compared to those who did only one type of training had better total cardiovascular improvements. (study)
So, to fully optimize your cardiovascular health, you’ll want to do both cardio and lifting as they both help with cardiovascular health (study). So if you choose to lift weights first, you’ll be getting some cardio benefits.
The third reason is that lifting weights has additional benefits by challenging your muscles and bones through better density and tendons to adapt.
The fourth reason is that lifting comes with visible benefits that are quicker to see, due to better fat burner and muscle-building. When you can see results, it’s a lot easier to stay in the groove of exercising when you know it’s working.
Lastly, many of us in our daily lives, are more likely to be walking briskly than picking up something heavy. So lifting weights typically is the weakest link to fix first.
If you’re looking for a way to get into lifting weights, starting with your body as the weight is a great way to get started. Check out our free bodyweight workout here. If you’re a man who’s lifting weights already, but you’re relatively inactive the rest of the week, try adding in some cardio. If you find your job is keeping you stuck at the desk and you drive to work, you might want to consider doing some cardio. You might come to enjoy it, especially if you can get outside in the sunshine and fresh air.
How much cardio should I do?
A joint statement from the CDC and the American College of Sports Medicine recommends doing at least 30 minutes a day, every day of the week (review). See if you can get out for a brisk walk outside during lunch or right after dinner.
The encouraging thing, is researchers say the effects of cardio are graded so that even bumping up your cardio fitness a little bit will go a long way in terms of health improvements (similar to the Pareto principle where 20% might get you 80% of the results.)(study). So if the “optimum” amount of cardio is soul-crushing and makes doing cardio seem impossible, take comfort in knowing that even doing a little bit will pay off.
How do I know if I’m progressing with my cardio workouts?
If you’re a numbers guy, in this study, vo2 max is one of the best tools we have as a snapshot of your cardio health and the risk of diseases (study).
Otherwise, if you’re doing a brisk walk, try and get further at the same time. So, if you want to do 30 minutes of cardio outside, go for a walk and set a timer on your phone for 15 minutes. See how far you get, then turn around. With the same amount of effort, if you’re getting further, chances are you may be getting better power output from the oxygen your cardiovascular system is cycling around.
Summary
- Cardio helps to keep your cells young.
- Cardio helps you learn better, have a better memory, make better decisions, and improve your thinking.
- Cardio helps to fight off anxiety, depression, and a bunch of other health problems.
- Cardio might help bring more blood flow to your head and help with hair loss.
- Consider doing cardio outside to get more UV rays from sunlight to help fight calcification. That will help with heart health and your hair.
- Cardio helps to fix erectile dysfunction, a problem for more and more young guys.
- Lift weights first to get into the habit of exercising, then add in cardio once you get the hang of it.
- Aim for 30 minutes and up of cardio a day.
- You can do low, moderate, or high intensity. They all come with health benefits. It might be wise to include all types in your life.
You may notice that it won’t take too many cardio sessions before you get the benefits. You should be feeling energetic, your thinking is clear, and you may even see some strength gains when it comes to lifting (blog article). Plus, your wife may even comment on your fuller, thicker hair, and the perked up version of you!
