I still can’t believe The Biggest Loser happened — and ran for 17 seasons. When I think about that show, I mainly remember deranged trainers screaming “LAST CHANCE WORKOUT” as contestants in soaked cotton tees did everything in their power not to slip off the treadmill.
The show was a spectacle of punishment, and borderline barbaric. But it was also aggressively unscientific, disseminating concepts that wormed into American brains and stayed a while, even as study after study concluded that rapid weight loss through extreme exercise and rock-bottom calorie counts slows down the metabolism, while all but guaranteeing you’ll gain it all back (as so many contestants did).
In the years since The Biggest Loser ruled Tuesday prime time, leading nutrition scientists and evolutionary anthropologists have dismantled many of its core assumptions. Chief among them: A) that more movement automatically means more calories burned, and B) that cardio is the key to shrinking your waistline. Still, the myths persist. According to a Cleveland Clinic survey, 51% of Americans say weight loss is their primary motivator for engaging in exercise.
Even as workout culture has welcomed a series of positive evolutions — from the rise of classes and clubs, to helpful apps and gamified machines — it’s common for Americans to put too much pressure on cardio. A couch-to-cardio swerve is still a leading choice for adults trying to get whipped for a wedding, svelte for summer, insert whatever alliterative cliche you like. And in an age of endless, self-appointed wellness influencers, there’s more misinformation out there on the topic than ever.
So let’s cut through the noise — first, by reinforcing why cardio isn’t a weight-loss silver bullet. And then, more importantly, by exploring what cardio ideally should be for.
17 Miles in Charleston
We ran through the Holy City, chasing bridge views, salted-lime lagers and lowcountry calmModern Hunter-Gatherers
There’s an extremely useful (and pretty famous) study for grasping the latest cardio-calorie research. It involves the Hadza people, a hunter-gatherer tribe in Tanzania. Still all but cut off from society, the Hadza spend their days shooting impala with poisoned arrows, catching lungfish and foraging for berries and tubers. It’s an active lifestyle, obviously.
Around 200 miles to the northeast, adults in Nairobi, Kenya, increasingly have access to all the creature comforts of the modern employee-industrial complex: cars, screens, grocery stores — and they enjoy a sedentary existence Americans are all too familiar with. Which group do you think burns more calories?
It’s not the Hadza people. In fact, both the tribespeople and industrialized adults throughout the world burn about the same amount. That’s because human beings operate within a fixed “energy budget” — move your body more, and the body doesn’t just keep burning calories. It readjusts, spending less energy on various processes, in order to keep your overall expenditure the same. As Duke University’s Herman Pontzer figured out, this is an evolutionary safeguard.
The Work of Dr. Herman Pontzer
An expert in biological anthropology and the author of Burn, Pontzer published a number of studies explaining what he dubbed “the exercise paradox.” Basically, exercise increases calorie burn in the moment — Strava’s not lying, you really did burn 1,000 calories on your eight-mile run — but the body compensates behind the scenes. You can’t outrun this core truth.
As Pontzer said in an interview with Harvard’s Colloquy Podcast: “For a half a billion years of evolution in animals, losing weight’s been a really bad sign. Right? If you’re losing weight, your economics are not sustainable…. [The Hadza do] about five to 10 times more physical activity every day than the typical American…but when you account for things like body size, fat percentage, age…there is no discernible difference in the total calories burned per day.”
What Can You Do?
Enlightening as Pontzer’s work is, some have worried that it might discourage the public from engaging in aerobic exercise altogether. And as we mentioned earlier, the majority of people exercise to lose weight, so those concerns are legitimate.
But in a positive light, the research also invites questions on the role of diet in energy expenditure and weight loss (it’s huge!) and curiosity for exercise patterns that are better at catalyzing fat loss (like HIIT).
Beyond that though, I think it grants us an opportunity to enlist cardio for a completely different — and ultimately more healthy and sustainable — reason. That being its impact on cognitive function, in the realms of mood, memory, focus, stress relief and long-term brain health.
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I try to stay off Instagram these days, because I think it’s a waste of time and my algorithm is absolutely cooked. But once in a while I log on, and there’s one video series that always makes me smile.
It’s this mustached 20-something guy who suffers from long corporate days — and regularly self-medicates with a sunset run down New York’s West Side Highway. When the videos start he looks like post-work Mr. Incredible. By the end of the video, five miles done, he’s beaming, and usually asking a stranger to record him doing a C+ cartwheel.
As with all social media, this is a performance. But it’s a much less sinister one than I’m used to in the wellness influencer-sphere, and critically, an apt display of my daily relationship with aerobic exercise. When a run starts, I’m a zombie. When it’s over, I’m feeling energized, hopeful and self-satisfied.
Short-Term High
When we think about cardio’s mood-boosting properties, we usually think about two things: running and endorphins. But any aerobic exercise — cycling, rowing, swimming — is capable of catalyzing immediate mental benefits; and these days, researchers have actually turned their attention from endorphins to endocannabinoids.
While the former can’t pass the blood-brain barrier, and likely don’t directly affect mood in the brain, the latter circulate freely through the bloodstream and can induce a feeling of contented calm. You may recognize the root “cannabinoid” — yes, these molecule resemble some of the active compounds found in marijuana. Only in this case, you’re making them yourself, after 20 minutes or so of continuous movement.
Some justice for endorphins: not only are they capable of relieving pain and encouraging overall physical relaxation, they bind to receptors that can boost dopamine. We’re used to vilifying dopamine these days (as it’s at the root of our many addictive vices), but here it’s a good thing. You want aerobic exercise to feel rewarding. That’s how it becomes habit-forming, in the best possible way.
That means more mood-boosting sessions, and as I’ve discovered: kinder, calmer days. It’s so much easier to focus, make sound decisions and actually listen to loves ones when I’ve activated my brain in this way. Cardio is one of the healthiest ways to build emotional resilience — one session at a time.
Long-Term Growth
One of my favorite cardio factoids: it’ll Jimmy Neutron-ize your brain. It’s true: “Aerobic exercise training increases the size hippocampal volume by 2%…leading to improvements in spatial memory…[and] effectively reversing age-related loss in volume by 1 to 2 [years].”
Consistent aerobic efforts also increase white and gray brain matter, lead to less diseased brain tissue and boost neuroplasticity, which is your brain’s ability to rewire itself, stay flexible and adapt as you age. Cardio even supports neurogenesis, which is the creation of new brain cells. In other words: it’s a dementia-prevention toolkit. And considering that 42% of Americans 55 and older are at risk of developing dementia, solidifying your routine now is a no-brainer.
Plus, when you stack up all those mornings or evenings where cardio has boosted your mood, cardio becomes an “all-natural” way to ward off depression. It morphs from a dreaded chore to a beloved home base. Feeling out of sorts? It’s always there for you, in whichever iteration you prefer.
I wish this was the sort of message being taught to Biggest Loser contestants decades ago, but suffice it to say: that sort of show would’ve never been made. In the end, cardio isn’t a punishment — it has less to do with losing something than with keeping what matters most.
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