Every gym (real gym) has a dude like this—we used to call them “fire plugs” (if you’re not from New York, that means fire hydrant). He has arms like sewer pipes, a chest like a gun safe, zero degrees of V-taper, and he’d probably be proud of the fact that he has a squat rack in his living room in case he needs some extra sets—your basic Midwestern corn-fed Jethro type. The exact guy you would never imagine seeing on a treadmill.
Cardio? That’s what people do when they don’t have huge muscles to worry about. Besides, he can see his abs (ab, actually, but it’s like a rock). What more evidence of health could anybody possibly need?
That depends on how long Jethro wants to live. A study recently published in Medicine & Science in Sports & Exercise looked at 562,234 adults who had undergone clinical treadmill testing. Researchers wanted to know whether measuring cardiorespiratory fitness improved predictions of who would die over the following decade, beyond the usual suspects: age, sex, high blood pressure, diabetes, cholesterol problems, and smoking. The answer was yes. Not because the treadmill possesses magical cognitive powers, but because how much work your heart and lungs can support tells doctors something the other numbers don’t.
METs, Exercise Capacity, and Mortality Risk Breakdown
The researchers measured peak exercise capacity in Metabolic Equivalent of Task (MET). It’s a way of expressing how much energy a physical activity demands relative to rest. In the study, the bottom fifth of fitness fell below five METs. After adjusting for traditional risk factors, the estimated ten-year mortality risk in that least-fit group was 32.9 percent, compared with 13.4 percent among the fitter participants. That’s a considerable difference, even allowing for the fact that these were people referred for clinical exercise tests, not a random cross-section of every healthy person walking around America.
Another number worth understanding correctly is that each additional MET of measured fitness was associated with a 16 percent lower hazard of death over follow-up. Notice I said associated. Not caused. The researchers did not take half a million people, put some on treadmills, leave the others on the couch, and wait ten years to see who was still kicking. This was an observational analysis. Healthier people may be able to exercise harder because they’re healthier in the first place. The study accounted for several major risk factors, but it cannot eliminate every possible explanation.
Nor did adding fitness transform mortality prediction into a crystal ball. The model’s discrimination score improved from 0.662 to 0.682 when cardiorespiratory fitness was included. That’s statistically meaningful and potentially useful, but modest. The headline isn’t that doctors can now tell you the day you’ll die by watching you jog, but rather that a basic measure of physical capacity deserves a seat at the table alongside blood pressure and the rest of the measurable health markers.
Strong Is Good, But Don’t Completely Write off Cardio just Yet
What I find fascinating is the cultural blind spot this exposes. Bodybuilders understand that muscle matters, as do strength, bone loading, glucose regulation, mobility, and the ability to get yourself up off the toilet when you’re eighty—all excellent reasons to keep lifting. Somewhere along the line, a segment of the iron community decided that cardio was bad. It was either an inconvenience or an enemy that ate muscle, or both. A lot of old-school, Arnold-era bodybuilders didn’t do cardio. Then suddenly the Life Cycle was invented, and a lot of us felt good about adding endurance training to our mix, mainly because of the massive calves and quads we started to see on Olympic cyclists. So, maybe there’s something to this? Blasphemy!
Until you consider your heart and your potential lifespan, with or without cardio and with or without muscle.
Of course, if you’re a bodybuilder, you’re going to take an extremist position. But you don’t have to become a distance runner. In fact, if your knees, hips, or general disposition object to running, there are bicycles, rowing machines, swimming pools, incline walks, and any number of ways to get your breathing up without pounding pavement. The practical target isn’t to chase a laboratory number you saw in an article. It’s to build enough aerobic capacity that ordinary life doesn’t feel like a stress test. Start where you are, progress gradually, and if you have symptoms or known heart disease, get medical guidance before going all out.
I still think a man should be strong. But if he’s strong enough to deadlift a Buick and gets gassed carrying groceries up one flight of stairs, we might have overlooked something. For the slight handful of you who compete at a very high level, doing cardio is etched into your coach’s DNA at this point. You have no choice. Except to keep doing it after the show is over. The rest of you, do cardio! Times have changed, technology has changed, and research has accumulated. Adding these data to the mountain of evidence thus collected on the topic, the overall consensus, if your desire is longevity, is simple: the lighter, stronger, leaner, and more cardiovascularly fit you are, the longer you get to bother everyone.
