How much cardio is enough to get your heart and lungs functioning as efficiently as possible? Hmmmm…. There are only two cardio days per week in Tony Horton’s P90X — Plyo and Kenpo, with the option to throw Cardio X into the mix if you like — but I had always heard that three times a week is the minimum to achieve at least minimal fitness. So is two times a week enough to build my heart and lungs?
I have, in my quest for fitness, read various things about cardio, and, while I can’t remember where I saw this, the following rings truest.
You are born with your heart a certain size. You are born with your lungs a certain size. They grow with your body, but you cannot manipulate them to be larger, i.e. working out does not make your heart and lungs grow, thereby making you more fit.
This makes sense to me. The heart and lungs are situated in your chest, behind ribs, so how can they get larger without banging into ribs. That can’t be right. This also helps me understand the phenomenon that I hear about every so often where an athlete is suffering from an “enlarged heart.” I had often wondered, “Isn’t that good? Wouldn’t we expect athletes to have enlarged hearts?”
If that is true, if your heart and lungs are what they are, how do we make them more efficient? I mean, they are getting more efficient as we work on our fitness, right? It is obvious without even formal measurement that, if we do P90X, we get better at Plyo and can go harder in Kenpo. If our heart and lungs are not growing, what’s going on?
You’ve probably guessed it: The muscles we use to do Plyo and Kenpo are getting better at doing those moves. This puts less stress on our heart and lungs, because with more efficient muscles, the heart and lungs can work less to feed them. This results in what we perceive to be improved functioning of our cardiovascular system. Sure, those activities are enhanced by our fitness, but what’s really happening is that our muscles are really the pieces of the system that are improved, so everything else that works to make them function works more efficiently, too.
And that is why the muscle confusion that Tony Horton stresses in P90X and One-On-One is so important. We have to do a variety of moves to achieve overall fitness. People who run all the time get really good at running, because their muscles are accustomed to the moves that occur when running, but when they are asked to do other things ….
I have personal anecdotal evidence of just this phenomenon.
When I was in the Air Force, we used to have to run 1.5 miles in a certain amount of time to pass our annual fitness test. Many of us, then, would run to stay in shape. Well, one year, someone higher up the chain of command came up with the idea to use bicycle fitness tests instead of making everyone run. They’d hook us up with a heart rate monitor and measure our pulse as we pedaled and the tester increased the tension on the stationary bike.
Many of us still passed the test, but there were a few runners who, for some reason, just could not. One guy — not the top runner among us, but up there — was a stand out. Everyone knew he was in shape. Just look at him! And he was still running, competing in half-marathons. Competing, mind you, not just completing. But he couldn’t pass the bike test.
He was really good at running. His muscles were used to those movements. But the bike test, not so much.
So you know what he did? He added some bicycling into his fitness routine. And you know what happened? After three months he passed his fitness test.
So, back to the original question: How much cardio we need to increase the efficiency of our hearts and lungs. Hmmmm…. Isn’t it obvious? If all this is true, and it seems to make sense, we don’t need any cardio to do that. We just need to build the muscles that we’ll be working, increase their efficiency, and the heart and lungs will work more efficiently, too.
But that doesn’t mean we don’t need cardio at all, because cardio does seem to, at the very least, improve brain function and lower stress levels, so gotta have that cardio. And if your goal is to be great at running, then, yeah run, run, run. But if you are shooting for general fitness, don’t forget to mix it up.
