Interesting stuff here, particularly in the Muscular Aging Trial section on how strength and muscle predict life expectancy.
Interesting stuff here, particularly in the Muscular Aging Trial section on how strength and muscle predict life expectancy.
It’s 100 degrees in my Las Vegas garage gym as I crank through another round of squats and all-out air-bike intervals, trying to block out the creeping pain in my legs, lungs, and —well, hell — everywhere else. Just keep moving, I tell myself. Faster, faster. When the reps are done, I’m destroyed: I hit the hot concrete floor and begin hyperventilating and punching my legs to flush the pain. My German shorthaired pointer tilts his head and gives me a baffled look that crosses mammalian distinctions. “Dude, what are you doing?”
I began training like this, five hard hours a week, nearly two decades ago. Roughly 4,500 hours of my life have been spent in a state of exercise-induced discomfort, and I’m not always sure why. Men have a lot of reasons for working out. Vanity and performance are the big ones. But I quit giving a damn about my abs after I got married, and I really don’t care who I can beat in a pushup competition or organized footrace. The most recent line I’ve fed myself is that all this time sweating is good for my health. It’s going to give me more, better years on earth. But as I lie on the garage floor gasping, I ask myself: Why do I exercise so hard, and so often, at age 32? Is all this manic exercise worth it? And if it isn’t, then what does training for more, better years look like?
Thanks to research, we know that a person’s heart can have a different age from that of, say, his kidneys or his brain, which is to say different organs within a single human body can show varying degrees of stress and strain. (Which, if you think about it, is really all age is: a manifestation of how much stress or strain your body has endured and exhibits.)
But we also know that for the average guy — let’s call him “you” — lung health and mental speed peak around your mid-20s. Beginning at age 30, your muscle strength and size start decreasing by about 3 to 8 percent per decade, and cardiovascular endurance dies off by about 1 percent a year. By 40, you’re slower on your feet. Once you hit 50, your brain is shrinking and bones are softening. From 60 on, it’s Murphy’s Law: What can go wrong will go wrong, all aches and pains and doctor visits. Then you hit age 76 and, if you’re like the average American male, you die.
The Science of Your Fitness Age
Theories on why this happens abound: Your telomeres, caps on the ends of your DNA, shorten and prevent your cells from dividing; free radicals cause your cells to accumulate damage; your endocrine system loses its ability to regulate hormones; and so on. Yet I couldn’t tell you the length of my telomeres, or what free radicals have done to my body, or the efficiency of my endocrine system. The shit’s too abstract for anyone not in a lab coat.
There might be a more basic answer. The National Institutes of Health recently bet $170 million on a program called Molecular Transducers of Physical Activity in Humans. Researchers from around the country will collaborate in a consortium within the program, known as MoTrPAC.
The goal: to better understand the health benefits of exercise at the molecular level. These researchers will investigate the biology--altering phenomena that may not only slow your aging clock but even turn it back, helping you feel and perform as if you were decades younger than what’s on your birth certificate. Scientists have a name for it: fitness age. And its primary metric is something even a meathead can and does quantify: fitness. “Exercise is medicine. We know that when you exercise, your muscle pro-duces beneficial compounds that circulate and communicate with the liver, bone, heart, brain, and more,” says Scott Trappe, Ph.D., director of the Human Performance Laboratory at Ball State University, who leads one of the 23 research sites involved in MoTrPAC.
And so a few months ago I set out to find my true fitness age, working closely with Doug Kechijian, D.P.T., cofounder and owner of Resilient Performance Systems in New York City, and Michael Fredericson, M.D., professor and director of the Physical Medicine and Rehabilitation division at Stanford University, to invent a fitness-age formula that would incorporate all different kinds of metrics. Would I be younger or older than the 33 candles on my next birthday cake? Have those 4,500 hours of fitness-related discomfort all been for nothing?
If you want to put their formula to the test yourself, try this six-step trial.
Pushing VO2 the Max
Discomfort is something that Ulrik Wisløff, Ph.D., knows intimately. He is a professor of exercise physiology at the Norwegian University of Science and Technology, and his specialty is cardiac fitness, specifically VO2 max, which measures the maximum amount of oxygen your body can use during exercise.
Wisløff, 50, has measured the VO2 max of 5,000 Norwegians, and his research has made him skeptical of time: Tell him about your habits and he’ll tell you why your birth certificate is bullshit. In 2006, he coined the term “fitness age” and created the fitness-age calculator. Go to the World Fitness Level site, plug in some info — age, waistline, resting pulse, how hard and often you exercise — and his algorithm spits back your fitness age, which, he claims, is your true age. “So you could be 50, but if you have the fitness age of a 30-year-old person, you are really 30 years old,” he says. The reverse is true, too.
Wisløff’s algorithm estimates your number by comparing your age, heart rate, and activity level with the data he’s collected. If the calculator tells you your fitness age is, say, 40, it means you have the VO2 max of the average 40-year-old. His papers have been cited more than 20,000 times (most exercise studies are lucky to be cited twice), and Garmin now incorporates fitness age into its activity metrics.
Even if you do exercise “enough,” the exercise you are doing may be insufficient.
The calculator has a legit health utility: “VO2 max has been shown to be the single best predictor of current and future health,” says Wisløff. The American Heart Association agrees. It also says that cardiorespiratory fitness forecasts impending death better than established risk factors like smoking, hypertension, high cholesterol, and type 2 diabetes. The higher your VO2 max, the bigger your dose of age-bending medicine, Wisløff explains. The point at which you optimize health by exercise and significantly drop your fitness age is when you are able to generate 10 to 12 metabolic equivalents of tasks, commonly known as METs.
Based on oxygen consumption, METs are a measure of exercise intensity. Sleeping is one MET. Walking 4 miles per hour earns you five METs. Running about 8 miles per hour or cycling 16 miles per hour scores 12 METs.
Building the fitness to hit 12 METs is where it gets tricky. Wisløff found that standard aerobic-exercise advice—150 minutes of moderate activity or 75 of vigorous activity weekly—is flawed. Forget that only half of Americans meet the aerobic-activity recommendations. He says that even if you do exercise “enough,” the exercise you are doing may be insufficient to make you truly fit.
“The problem is these numbers don’t account for intensity and don’t reflect how your body responds to a certain activity,” Wisløff says. If you’re not challenging yourself, building an ability to hit or exceed 12 METs, you’re not optimally protected against disease.
This notion led Wisløff to study the impact of high-intensity interval training. His research indicates that intervals are ideal for spiking your VO2 max and challenging your heart, which in turn adapts by increasing the amount of blood each beat pumps, boosting oxygen delivery.
Putting the Theory to the Test
Wisløff created the calculator because, like telomere length, VO2 max is a figurative and literal pain to measure directly — a fact I would learn for myself. To put his theory to the test, I head to the University of Nevada, Las Vegas. I enter the physical-education complex, a 140,000-square-foot Cold War-era research compound just a mile from the casinos of the Strip. Ph.D. student Nathaniel Bodell is waiting for me in the exercise-physiology lab. He stoops over a computer that’s flanked by treadmills, erg bikes, and squat racks. After making small talk, he straps a mask onto my face, has me stand on a treadmill, and punches a few buttons that initiate a VO2-max test. The belt kicks. I start stepping. “Just so you know,” says Bodell, “this won’t be the most comfortable thing you do today.”
The first four minutes of running are easy — slowly ramping from a flat 2 to 5 miles per hour — but soon I’m running 7.5 miles per hour and Bodell is increasing the incline. The mask clamped to my face is calculating how many oxygen molecules I breathe in and out. The fewer oxygen molecules I breathe out relative to those I breathe in, the better my body is at shuttling oxygen from my lungs to blood to working muscles.
Bodell increases the incline by 2 percent every minute or so, making the test progressively more difficult. The longer I run before tapping out, the higher my VO2 max and, according to stacks of medical literature, the further I am from the most popular ways American men die. The treadmill has been spinning for 15 minutes, and I’m running 7.5 miles per hour at a 12 percent incline. I tap out. Bodell cuts the speed, then walks to his computer to analyze my numbers as I remove my mask and heave for air.
There’s more to understanding the aging process than what you can find out from a treadmill run.
“Uh, are you a runner?” asks Bodell.
“I trail run a day or two a week and can hold a sub-seven-minute-per-mile pace.”
“It shows,” he says. I register a 64.9, and I can hit 19 METs. According to Wisløff’s fitness-age protocol, my fitness level is aligned with someone under 20 years old. Maybe those thrice-weekly HIIT workouts are really worth it.
Wisløff’s idea for deriving fitness age — stratifying a person’s “true” age based on cardiac capability — is intriguing, but I can’t help thinking there are other variables that have to be factored in. Look at serious endurance athletes. Sure, their VO2 max is off the charts, but they look like they’re on the tail end of a hunger strike, and they’re weak as heck.
Some researchers disagree with Wisløff and think he’s overemphasizing VO2 max. Many experts I spoke with — people who study other fitness markers and work with average guys day in and day out — argue there’s more to understanding the aging process than what you can find out from a treadmill run. That the most important data requires no complicated masks or lab software — just old-school iron and a little grit.
Muscular Aging Trial
“Muscle is king,” says Andy Galpin, Ph.D., a muscle researcher at California State University, Fullerton. “It causes, controls, and regulates your ability to move. If you lose muscle quality and can’t move, everything else fails quickly.”
Healthy muscle controls blood-sugar levels and mitigates over-inflammation, which is implicated in pretty much all the diseases that’ll kill you. Powerful muscles may be just as important as a powerful heart regarding mortality: Swedish researchers found that the strongest among a group of men of all ages were the least likely to die over two decades compared with those with the least muscular strength. And in creating a formula to calculate my fitness age, Kechijian and Dr. Fredericson insisted that I test my strength in four key areas.
First up: a trap bar (a barbell shaped like a hexagon with two handles). I step inside the bar, which weighs 170 pounds (also known as my body weight), grab its handles, then stand, lifting the weight. I walk with it 100 feet across the floor. This task, a deadlift to farmer’s carry, tests three qualities: handgrip, lower-body strength, and the ability to carry weight over ground. Men with the strongest handgrip and greatest muscular strength reduced their risk of death by 31 and 14 percent, respectively, according to a recent review.
Next I go for 300 pounds, 1.75 times my body weight, an optimal metric for health. I stand inside the trap bar, grip it, rip it—and it rises. I stroll the 100 feet. Pass.
On to strength test two: pushups. The classic exercise tests whether you’re strong for your body weight. Further evidence that relative strength is linked to mortality is revealed by the obesity paradox: Obese people are more at risk of various ailments, like heart disease. But unfit, obese men with heart disease had a lower 13-year mortality risk compared with their normal-weight counterparts, according to a study in Mayo Clinic Proceedings. One possible reason: Obese people tend to have more muscle and strength, due to carrying their own weight. Build adequate strength without the fat and you’ll likely avoid disease and be in better shape to beat it if you get it.
I drop to the ground and crank out my reps, reaching 40, which is 12 more than the target number for optimal aging for guys in their 30s, according to Dr. Fredericson, citing recommendations from the Mayo Clinic.
Time also changes the very composition of your muscles, which comprise an array of fiber types. At the most basic level you have Type I and Type II fibers, and hybrids of the two. Pure Type I fibers drive slower, everyday movements, while pure Type IIs power explosive movements. Time plus inactivity shifts the balance to Type I fibers, one reason older people tend to move more slowly. The smaller your Type II fibers, the seemingly older your muscle.
No matter your age, you want to build a reserve of strength and muscle.
Doing only VO2-max-enhancing activities—cycling and running—tips the balance no matter your age to Type I fibers. The worst exercise approach is doing nothing, but you’re massively compromising your health if you’re doing only cardio.
Consider the findings of a study in the European Journal of Applied Physiology. The researchers compared two identical twins, men with the exact same DNA but 30 years of different exercise habits; one was not a regular exerciser and the other was an endurance athlete.
As you’d expect, the endurance twin had a healthier cardiovascular system—better blood pressure and lipid panels, higher VO2 max. “But he had no better strength or muscle quality,” says Galpin, who led the study. He actually had far more Type I muscle fibers than his sedentary twin. The lesson: Chasing one form of exercise at the expense of all others improves some health metrics, but it weakens other critical links in the aging chain.
For test three, I grab a jump rope, which I’ll use to assess my Type II fibers. I begin skipping rope, bouncing off both feet, then transition to jumping on only my right. “1, 2, 3, 4 . . .”
This tests my coordination, too. Falls kill roughly 33,000 Americans a year. “Let’s say you trip,” says Kechijian. “Your ability to recover has little to do with balance and everything to do with your ability to quickly shoot your foot or arms out to stabilize yourself.” That’s all coordination and Type II fibers. “. . . 48, 49, 50.” I hit 50 skips on my right foot, then repeat on my left, optimal numbers for each side.
Strength is varied, though, and we need to measure more. The final strength test is the Turkish getup, which focuses on my movement and ability to rise from the ground. People who were unable to get up using only their legs were five times more likely to die over a six-year period, according to a study in the European Journal of Preventive Cardiology. I grab a 24-kilo kettlebell and lie on my back, bell overhead. The task: get up while keeping the bell overhead. I ace it. Not everyone can.
“No matter your age, you want to build a reserve of strength and muscle,” says Trappe, the Ball State researcher. That becomes harder with time, but his research discovered that even 70-year-olds who lifted three times a week for 12 weeks improved their strength and muscle mass. The men who stopped lifting saw strength drop quickly, while the ones who kept up a once-a-week routine maintained their gains.
My fitness age is starting to come into focus. I’m definitely younger than my 32 years. I have the VO2 max of a 20-year-old, and I overachieved on all my lifts. Except my back screams otherwise.
Finding a Full Range of Motion
I call Kelly Starrett — a physical therapist and mobility guru who works with people ranging from Navy SEALs to elite athletes to Silicon Valley CEOs — and ask him what I’m still missing. “So many people chase infinite cardio or strength capacity,” he says. “You need just as much movement capacity. Many people go months without taking their joints through a full range of motion.”
That not only sets you up for disaster in the long run, but it also makes you more likely to experience aches, pain, and injury each workout. Starrett suggests a final test in my aging assessment, an overhead squat with a broomstick. How hard could it be?
Forget strength and cardio. This test challenges total-body mobility, which many experts believe could be a key to preventing age-related degradation. Populations in Asia and the Middle East who do many activities in the squatting position, for example, see little to no hip and lower-back diseases. In the U. S., the number of hip and back -surgeries performed continues to increase each year.
I stand with my feet under my shoulders, raise the stick overhead, push my hips back, and begin to descend. My goal is to lower into a full squat, feet flat on the floor. Things go smoothly until I hit parallel; I can’t go deeper without peeling my heels from the ground or tipping my torso and arms forward.
This is old-man movement, but it’s not uncommon among guys my age, even those who work out. Starrett says that’s because we see the gym as a great place to build strength and capacity, but we don’t care to just move.
That’s a mistake. Research in the Journal of Evolution and Health suggests movement creates both localized and whole-body changes. Furthermore, moving through full ranges of natural motion — for example, a full squat with your arms overhead — may jump-start dormant cells that fight aging. The data suggests that people who move in a variety of ways have significantly longer telomeres than less active people.
Your movement capacity is only as old as you’ve made it, says Katy Bowman, a physical therapist, biomechanist, and author of Move Your DNA. Kids have full command of their joints and can easily squat, lunge, lift overhead, and more. But mobility is a use-it-or-lose-it proposition. Those kids eventually sit at school desks, then join average Americans at work, sitting roughly six to eight hours a day, according to the CDC.
There is no more of a complex system than a human being.
When adults do move, it’s typically through a few repetitive motions, like walking and getting in and out of a chair, says Bowman. A standard workout of cycling, running, some bench-pressing, and curls is beneficial, yes, but we aren’t moving enough or with enough variety to slow the loss of movement, says Bowman, or avoid injury, says Starrett.
That’s my problem. My cardio engine is huge at the expense of mobility. Movement is my weak link, the “oldest” part of my fitness. My lack of complete movement may have caused cellular maladaptations, making me more likely to have shorter telomeres, according to a study in Medicine & Science in Sports & Exercise.
Cellular maladaptations? Yikes, I need to start doing significantly more mobility training.
Managing Our Complexities
Through all the research and testing, I can’t help thinking of something Starrett told me. “There is no more of a complex system than a human being,” he said. “So many factors can predict health and longevity. We should move away from trying to choose a single silver bullet.”
Believing you have that silver bullet can cause you to miss the target on overall health. “I think we need to step back and challenge what we’re doing exercise for,” says Galpin. “What you really want for general longevity and wellness is to stimulate, challenge, and stress the body internally, in multiple ways. What you actually do to get there—your actual workout—it’s just noise.”
After all the testing, I run the numbers laid out by the experts and discover my fitness age is 28, even with subpar mobility. I’ve bought my body almost a half decade.
I still do five weekly workouts, but they’re different. Most are no longer an exercise in the art of suffering. Sure, I still occasionally push the intensity—it helps relieve stress. But it’s no longer a compulsion. All out all the time, I now understand, won’t give me as big a return on time and effort invested as I once thought. What will? I’ve traded a running session for a workout in which I forget the numbers on the stopwatch and barbell and focus entirely on improving my mobility. I’ll even count a long walk through the desert with my dog as a workout, a moving meditation that improves my health, my mind, and the quality of my years.
Has my fitness slipped? Doubtful. Push me and I can do all the things I could before. But those hip and back pains that used to come alongside the doing? They’re long gone.