Energy, and How to Get It

For months, during the main pandemic stretch, I’d get inexplicably tired in the afternoon, as though vital organs and muscles had turned to Styrofoam. Just sitting in front of a computer screen, in sweatpants and socks, left me drained. It seemed ridiculous to be grumbling about fatigue when so many people were suffering through so much more. But we feel how we feel.

Nuke a cup of cold coffee, take a walk around the block: the standard tactics usually did the trick. But one advantage, or disadvantage, of working from home is the proximity of a bed. Now and then, you surrender. These midafternoon doldrums weren’t entirely unfamiliar. Even back in the office years, with editors on the prowl, I learned to sneak the occasional catnap under my desk, alert as a zebra to the telltale footfall of a consequential approach. At home, though, you could power all the way down.

Still, the ebb, lately, had become acute, and hard to account for. By the standards of my younger years, I was burning the candle at neither end. Could one attribute it to the wine the night before, the cookies, the fitful and abbreviated sleep, the boomerang effect of the morning’s caffeine and carbs, a sedentary profession, middle age? That will be a yes. And yet the mind roamed: Covid? Lyme? Diabetes? Cancer? It’s no HIPAA violation to reveal that, as various checkups determined, none of those pertained. So, embrace it. A recent headline in the Guardian: “Extravagant eye bags: How extreme exhaustion became this year’s hottest look.”

It was just a question of energy. The endurance athlete, running perilously low on fuel, is said to hit the wall, or bonk. Cyclists call this feeling “the man with the hammer.” Applying the parlance to the Sitzfleisch life, I told myself that I was bonking. At hour five in the desk chair, the document onscreen looked like a winding road toward a mountain pass. The man in the sweatpants had met the man with the mattress.

All of us, except for the superheroes and the ultra-sloths, know people who have more energy than we do, and plenty who have less. We may admire or envy or even pity the tireless project jugglers, the ravenous multidisciplinarians, the serial circulators of rooms, the conference hoppers, the calendar maximizers, the predawn cross-trainers and kickboxers. How does she do it? On the flip side, there are the oversleepers, the homebodies, the spurners of invitations and opportunities, the dispensers of excuses. Come on, man! It’s hard to measure success, if you want to avoid making it about money or power or credentials, but, as one stumbles through the landscape of careers and outputs and reputations, one sees, again and again, that the standouts tend to be the people who possess seemingly boundless reserves of mental and physical fuel. Entrepreneurs, athletes, artists, politicians: it can seem that energy, more than talent or luck, results in extraordinary outcomes. Why do some people have it and others not? What does one have to do to get more?

Energy is both biochemical and psychophysical, vaguely delineated, widely misunderstood, elusive as grace. You know it when you got it, and even more when you don’t. This is the enthusiasm and vigor you feel inside yourself, the kind you might call chi, after the ancient Chinese life force or the pronouncements of the storefront acupuncturist. The kind you seek to instill by drinking Red Bull or Monster, plunging into an ice bath, or taking psychostimulants, like Ritalin or Adderall or Provigil. Nootropics. Smart pills. CDP-choline, L-theanine, creatine monohydrate, Bacopa monnieri, huperzine A, vinpocetine. Acetyl-CoA, lipoic acid, arginine, ashwagandha, B complex, carnitine, CoQ10, iodine, iron, magnesium, niacin, riboflavin, ribose, thiamin, Vitamins C, E, and K. Biohackers microdose psychedelics, stick ozone tubes up their butts, or pay fifteen hundred dollars for a seven-hundred-and-fifty-milligram dose of NAD IV. Energy is why we’ve made a virtual religion of 1, 3, 7-trimethylxanthine, otherwise known as caffeine.

“Society has progressively increased its demands on us, and with that, therefore, our expectations of what we can or should do,” Maurizio Fava, the chief of the department of psychiatry at Mass General, told me. “This has led to a quest for greater ‘energy.’ ‘How can I do more? Doctor, what can you give me?’ ”

“Energy,” though, is a misnomer, or at least an elision. What we commonly call energy is actually our perception of the body metabolizing carbohydrates or fat as energy. Energy isn’t energy. It’s our experience of burning energy, converting it to work. It’s a metabolic mood. As Richard Maurer, a doctor in Maine who specializes in metabolic recovery, and who encountered me one day last summer as I mumbled about a shortage of it, told me, “ ‘Energy’ is a useless term. It is not the perception of stimulation. It is just the capacity to generate work. I think of it as only relating to potential. If a patient says, ‘I want more energy,’ maybe the doctor should just write a scrip for methamphetamine. But that’s false chi.”

The precise workings of the metabolic system, its nuances and contingencies, are, in many respects, an enduring mystery. You’d think we’d have figured out by now how our cells go about their business, this being the most fundamental element of our existence, but they may as well be in deep space or the Mariana Trench.

One and a half billion years ago, the planet’s only life-forms were single-celled. Fermentation ruled the earth. Then an anaerobic bacterium engulfed an aerobic bacterium. In time, the ingested bacterium’s capacity for feeding on oxygen managed to increase, by an order of magnitude, the amount of energy available to its anaerobic host. This accidental collaboration made possible the proliferation of multicellular life-forms and, eventually, tool-wielding hominids who would come to complain that they feel tired all the time.

According to what is known as the endosymbiotic theory of biological complexity, this chocolate-meets-peanut-butter moment, this big mush, is the reason we exist. That aerobic bacterium evolved into what we call mitochondria, the organelles that fuel living creatures: the powerhouses of the cell, as every schoolkid learns. (It’s about all I retain from high-school bio, anyway, save for Mr. Burns’s relishing his coinage of the phrase “a smidgen of lipids.”) Each of us has hundreds—if not thousands—of trillions of mitochondria. They convert glucose and oxygen into adenosine triphosphate, or ATP, the primary cellular fuel. They also help produce the essential hormones—among them estrogen, testosterone, and cortisol—and regulate cellular proliferation and death.

It’s not inconceivable that the rest of the body (brain, hands, heart, lungs, digestive tract) is merely an elaborate and sometimes clumsy apparatus for the nourishment of the mitochondria—that it is the mitochondria, and not Homo sapiens, who rule and foul the earth. Our cardiovascular system, that fantastic and vulnerable machine, is essentially a delivery system for the oxygen they require. The mitochondrion is the creature and we are merely its husk, its fleshy chrysalis. A newborn’s first breath? That’s the mitochondria, calling the shots.

“That, anyway, is the mitocentric perspective,” Martin Picard said, on a recent afternoon in his office, in Washington Heights. Picard, a partisan of that perspective, is a professor of behavioral medicine at Columbia University Irving Medical Center, where he directs a lab of about a dozen researchers. His work straddles the departments of psychiatry and neurology. His specialty is mitochondrial psychobiology. “We try to understand the connection between the mind and mitochondria,” he said. “We think about energy a lot.”

A lean Montrealer, with a gentle yet poised intensity that one might classify as medium-energy, Picard came at the question of vim and vigor from a near-cosmic vantage. His office, high above the Heights, had a commanding view down the Hudson, a receding sun-blanched shorescape of skyscrapers and tidal swirl that lent his pronouncements an oracular air. In a mostly sincere attempt to convey how little we know about the workings of consciousness, he said, “We have yet to disprove that our brains aren’t merely antennas, that all of our ‘thoughts’ and ‘memories’ don’t just come from out there”—he pointed out the window—“and that we’re not just ‘streaming’ everything.” Glancing behind him at the river’s eddying current, I half expected to catch a glitch in the matrix.

“The main distinguishing characteristic between a cadaver and a living, thinking, feeling individual is the flow of energy through the body,” he said. “The cells are the same, but without the energy flow it’s just an inert blob.”

Mitochondria transform chemical energy into electrical energy, Picard explained. “Communication and energy go together,” he said. “The organs and cells can’t communicate without energy. Cells talk to each other. The mitochondria, which used to be bacteria, talk to the gut microbiome. They are like cousins. Cells choose to do one thing or another, based on the energy available. Energy for cells is like emotions for a human. It causes them to make decisions that may not seem rational.”

Picard took me around the lab. He opened a cryo-storage tank—ice vapor wafting out—which contained cells of patients with mitochondrial disease, genetic defects that afflict at least one in five thousand humans. He pointed out other machines. Fluorometer, respirometer, real-time-PCR instrument, plate reader, Halo robot, a cellular-energy-consumption analyzer called a Seahorse. “This is our way to get to know the mitochondria, to challenge them and poke them,” he said. “It’s our way to ask them questions.”

A handful of doctoral candidates were at work. A research assistant was trying to determine whether women and men have different mitochondria. Mitochondrial DNA seems to be passed down from generation to generation exclusively by the mother; sperm contributes nothing. As a result, genealogists have been able to trace a matrilineal line from all living humans back to a woman in East Africa, our so-called Mitochondrial Eve, born an estimated two hundred thousand years ago. (Picard did his postdoctoral work, at the University of Pennsylvania, with Douglas Wallace, the evolutionary biologist who discovered that mitochondria are matrilineal and that mutations in mitochondrial DNA are a significant cause of disease. “He put mitochondria on the map,” Picard said.)

“The human body is a social network,” Picard said. He compared it to an ant colony, in which every ant has the same genome but serves a different purpose, much in the way the organs do for a human being. “My working hypothesis is that mitochondria do a lot of the sensing and perceiving and integrating of signals. That they are the cellular antenna, or little brains that receive, process, and integrate information.”

A student was filling plates with skin cells; each plate had ninety-six wells the size of apple seeds, and each of these contained twenty thousand cells. She was exposing healthy cells and compromised ones to stress, in the form of a synthetic version of cortisol. “A whole human life span, but in a dish,” Picard said. “Cells age faster if you expose them to stress. They burn energy faster. It’s as though cellular anxiety causes cells to breathe faster. They consume more oxygen. They’re wasting energy, and we don’t know why.”

People with mitochondrial disorders struggle to transform energy into ATP. “What they experience subjectively is constant tiredness and fatigue,” Picard said. “They don’t have the mojo. Fatigue is the No. 1 symptom—they feel tired all the time. And it’s a long diagnostic odyssey. So, yes, it seems people can sense when their intercellular energy state is low.” Another bit of circumstantial evidence: Amytal, or amobarbital, an active ingredient in truth serums developed in the United States in the thirties, essentially inhibits mitochondrial respiration, supposedly rendering subjects too worn out to lie. Amytal is also what Picard’s lab has used in some of its assays. “If you mess with the mitochondria, people feel shitty,” Picard said.

It can work the other way, too. A few years ago, Picard’s lab did a study in which ninety-one women reported their mood levels and submitted to mitochondrial tests for seven days. The study suggested that mood has a direct effect on mitochondrial health. Chin up!

By this point, I’d heard and read a lot about mitochondria—“the coolest independent contractors on the planet,” as Maurer called them. In “The Energy Paradox: What to Do When Your Get-Up-and-Go Has Got Up and Gone,” Steven Gundry, the well-known California cardiologist, describes “mitochondrial gridlock,” the overwhelming of these organelles with too much to do—too much junk. Gundry enumerates seven “deadly” energy disrupters: antibiotics, glyphosate (the main active ingredient in the weed killer Roundup), other environmental chemicals, overused pharmaceuticals, fructose, bad light, and electromagnetic fields. Thinking about all the inputs, their ubiquity, and the myriad unmappable consequences of their interactions, one may just sigh and reach for the Red Bull. Fake chi until you make chi.

Picard’s purview was perhaps more descriptive than prescriptive. “Energetic constraints, energetic flow, and the forces that drive energetic flow—these questions aren’t taken into account as much as they should be,” he said. “The way of the future is understanding personalized energy flows. The last ten years of personalized medicine has been taken over by genomics. The premise is that if you can sequence it you’ll know whether you’ll get sick or stay healthy. That’s where all the money goes. It’s a lucrative hypothesis, but it’s doomed to yield incomplete answers. The genome is static. Health is so dynamic.”

“People are somewhat gorgeous collections of chemical fires, aren’t they?” Harold Brodkey wrote, in the story “Angel.” “We are towers of kinds of fires, down to the tiniest constituencies of ourselves, whatever those are.” Some years ago, without thinking, I introduced two friends of mine, B. and M., to each other, in a loose crew of people meeting up in a bar before a concert. B. and M. were both married. “I love your energy!” B. told M. Everyone laughed: such cheese. The next day, he called me and asked for her number. Such trouble. M. began referring to him, when discussing him with others, as “Energy”; she liked his, too. Their marriages didn’t survive the radiative flux, and B. and M. now live together, in a gravitational field of their own, otherwise known as Essex County, New Jersey. (When I told M. recently that I was writing about energy, the kind you feel, she said, “Talk about how annoying it is that everyone says they are tired. Tired is universal. We are exhausted until we die.”)

B. and M.’s energy is of a different, albeit related, category—the kind you project, or perceive in others. This one has something to do with vigor as well, but also charisma, aura, and temperament. It has a spiritual dimension, to those who perceive or credit such phenomena, and a social one. In some circumstances, good energy may just be a matter of radiance, of good skin, teeth, hair, posture, which are in many respects themselves functions of robust health. Or it may comprise kindness, attentiveness, optimism, humor—the ability to make other people feel good about themselves. There may be intangibles at play. Pheromones, assurance, electromagnetics, pixies.

To the extent that there is an overlap between the kind of energy you feel and the kind you project—a three-part Venn diagram of bio, mojo, and woo-woo—the concept has an array of ancient antecedents. In the Upanishads, prana, Sanskrit for “breath,” is the vital breath that animates body and soul, and all of existence, much like chi. Posidonius, the Stoic, proposed the existence of a life force that emanates from the sun. (Picard, the mitocentric, also cites the sun: it initiates a life cycle—photosynthesis, glucose, oxygen, ATP—that happens to have mitochondria as its linchpin.)

Many of the variations on such ideas are pseudoscientific, the purview of quacks and crazies, or of spiritual adepts who may have been mistaken for them. Esotericism encompasses a variety of impossible-to-substantiate phenomena that persist best, in our quasi-scientific era, as metaphors or abstractions. In the eighteenth century, Franz Mesmer introduced his concept of mesmerism, or animal magnetism, involving a universal vital fluid that passes in and out through our pores. Baron Carl von Reichenbach, some decades later, described an electromagnetic substance he named the Odic force, after the Norse god Odin, which sensitive souls could perceive emanating from others’ foreheads. Early in the twentieth century, the French philosopher Henry Bergson identified an “élan vital,” which impels consciousness and evolution. Schopenhauer had his “will to live,” and, of course, for Freud, the source of the oomph within was the libido. Freud got some of his ideas from the work of the American neurologist George Miller Beard, who, in the years after the Civil War, had identified a condition called neurasthenia, arising out of the exhaustion of the nervous system. Headaches, fatigue, and impotence were the symptoms of what Beard called “American nervousness.” The cause, he proposed, was the stress of modern civilization, the most salient manifestations being “steam-power, the periodical press, the telegraph, the sciences, and the mental activity of women.”

And then there was orgone, discovered, or imagined, by Wilhelm Reich, the Austrian psychoanalyst and fallen Freudian. Reich—who fled Germany in 1933 and pursued his experiments in Norway and New York before settling in rural Maine, where he could keep an eye out for U.F.O.s—sought to find physiological proof of the libido. In the lab, he hooked his subjects up to an oscillograph (one of them was a young Willy Brandt, the future West German Chancellor) and, with a microscope, discerned pulsating particles he called “bions,” which he claimed were the source of a mysterious life force called orgone. Orgone, he said, was blue, and was responsible for the color of the sky. Later, he invented a device called the orgone accumulator, an insulated shed the size of an outhouse, lined with metal panels. Among other things, it was said to enhance orgasms; the subject, preferably naked, would sit inside and accumulate orgone. It accumulated adherents, anyway—including Norman Mailer, Saul Bellow, J. D. Salinger, and Sean Connery—despite there being no legitimate evidence of orgone’s existence or benefits. Reich’s machine inspired the Orgasmatron, in Woody Allen’s “Sleeper,” and Dr. Durand Durand’s Excessive Machine, in “Barbarella.” The federal government, suspicious of Reich’s free-love evangelism and his associations with Communists, hounded him for years, and eventually jailed him for shipping orgone accumulators across state lines. He died of a heart attack in 1957, at Lewisburg Federal Penitentiary.

A year ago, my wife gave me, as a gift, an Oura ring, my first so-called wearable. A hint, perhaps. I slipped it on next to the wedding ring, and it began feeding data about my exercise and sleep to an app on my phone. Yes, people have been using technology to track their steps and heart rates for a long time now—Fitbit, Apple Watch—but I’d considered such devices dorky, and vaguely sinister. Self-improvement can grate; data tracking can infringe. But maybe I needed a shove, and I was curious to see some numbers behind the brownout afternoons.

The Oura motivated me to get out and move—steps, miles, calories. I took long, aimless walks that I imagined would add weeks to my life, like injury time in a soccer match. (It would take a lot of injury time to make up for the hot dogs, if, as a recent study suggested, each one shortens the life span by thirty-six minutes.) Harder work, not surprisingly, yielded higher scores. Jog, or bike, or run stairs, then excitedly check the app. The lure of better numbers, more carrot than stick, was energizing in itself, even if the ring’s criteria seemed kind of arbitrary, maybe overgenerous. The instrument is blunt, but it will cut.

The ring also conditioned me to begin each morning with a Christmas-stocking jolt of anticipation. Oh boy, new data. “How’d you sleep?” my wife would ask, as one does.

“Don’t know yet.”

Most days, the numbers weren’t good: Santa leaves a lump of coal. My sleep patterns were lousy and seemed to augur an early demise. It turned out that what might feel like restorative slumber—after a keen night out, for example, or a bout of hard work—was instead my body struggling to process the poison I’d put into it. The time in bed was more work than rest.

The Oura emphasized the concept of “readiness”—a measure of recuperation. The relevant data point was heart-rate variability, or H.R.V. Your heart rate, like most of the body’s involuntary functions, is controlled by the autonomic nervous system, which has two components: the sympathetic nervous system and the parasympathetic one. The former fires the fight-or-flight impulse; it activates when you experience stress, or excitement, or overindulgence. The latter is the restorative impulse: “rest and digest,” “feed and breed.” The sympathetic system stimulates adrenaline, which dilates your pupils, raises your pulse, opens your airways, and interferes with signals to your bladder. (This is why fear can cause people to piss themselves.) The parasympathetic does the opposite—it settles you down. Ideally, these two systems achieve balance. You rev up, you calm down. You push, you heal. H.R.V. supposedly measures this state of concord. Counterintuitively, higher variability is said to reflect greater balance, and better health. Low H.R.V. correlates to a range of diseases and to earlier mortality. My H.R.V., especially after I’d had a few, was very low.

“You can only manage what you measure,” Will Ahmed, the founder of Whoop, another tracking device, told me last month. By now, I had on three wearables: the Oura ring, a Whoop band on my left wrist, and a Levels glucose monitor behind my left triceps. I’d heard about Whoop from a doctor and journalist named Bob Arnot, a standup-paddleboard masters world champion and competitive ski-mountaineering racer, and the author of the recent book “Flip the Youth Switch.” Dr. Bob, who is seventy-three, is a high-energy guy—maybe a freak.

Clearly, despite our best efforts, energy is not evenly distributed, whether because of genetics or fate, nature or nurture. People blessed with it may ascribe it to their own virtue, perseverance, or self-discipline, and will sometimes wield the descriptor “low-energy” as a slight, as though Eeyores are contagious. The idea that you can train, will, or even medicate yourself into a permanent state of pep, charisma, and accomplishment lends an atmosphere of piety to the energy-assessment dance. It’s all a matter of attitude, they say, as though attitude were not itself determined by energy. Think positive! It takes energy to change habits and alter circumstances. One can adjust certain knobs, but it can feel like a chore to deduce which knobs do what.

“I fundamentally believe this is something you have control over,” Arnot said, when I called him. He credited his apparently prodigious mental energy to what he called “associative thinking.” Lately, he’d been composing a trumpet concerto and studying Python, calculus, machine learning, Arabic, and Swahili. “I don’t sleep much. I’ve always been a hopeless overachiever. Whatever I do is the opposite of what I call ruminating.” Whoop, he said, had helped him maximize his workouts and his downtime. His H.R.V. readings got better each month (H.R.V. typically worsens as you get older), and he reckoned that his biological age was much lower than his chronological one.

Arnot connected me with Ahmed, a former Harvard squash captain, who told me that it was in deep sleep that you generate ninety-five per cent of your growth hormones: “That’s when you’re repairing the muscles you break down in the gym.” The gym. Right. For cognitive repair, it was REM sleep, the dream state that cleanses the brain. “Chess players focus on REM,” Ahmed said. According to both Oura and Whoop, my REM and deep-sleep numbers weren’t great. I was killing it, though, on light sleep, and not sleeping. Search “Orgone accumulators near me.”

“Energy is a real thing, and your perception of your energy can affect your levels,” Ahmed said. Ahmed himself always eats early and avoids sugar and alcohol in the evening. He wears blue-light-blocking glasses when, as he must, he uses his phone late (the light wavelengths from our screens, as we are often warned, disrupt our circadian rhythms), takes a cold shower and does breathing exercises before bed (favorite prescriptions of Wim Hof, the Dutch extreme athlete and life-style guru known as the Iceman), and uses blackout shades and an eye mask, aiming for more than five hours of REM and deep sleep a night. “I have never met someone who gets that much who isn’t leading a great life,” he said.

“Totally,” I said.

A Whoop representative had told me about Levels, which sent me a kit with a disk to stick in my arm for a couple of weeks. I began taking blood-sugar readings with my phone. Soon afterward, Casey Means, Levels’s co-founder and chief medical officer, checked in on me. Means, who is thirty-four, is a graduate of Stanford’s medical school and a self-proclaimed “recovering surgeon.” She cited a University of North Carolina study that found that eighty-eight per cent of Americans suffer from some metabolic malfunction. “That means that roughly one in ten of us is able to process energy the way our bodies are designed to,” she said. “It’s an epidemic. Our fundamental pathways have been hijacked by the Western diet and life style. Disordered blood sugar is a big driver of most inflammation and chronic disease. It’s not just diabetes.”

The Levels app revealed that even a banana or a piece of toast raised my blood sugar by an alarming amount. The flat line of the morning’s fast, once broken, would bend into the red. The app would post an exclamation point next to the spike on the graph and ask, “Did something happen?” Yeah, jerkface, I had breakfast. Then, two hours later, the numbers would begin to ebb. But it wasn’t as though I was feeling jacked on the way up and then whacked by the crash. It felt like not much. Until around 3:23 P.M.—the attack of the yawns. Following the instructions of Levels, I experimented, and soon discovered that fat and fibre—a slab of bacon, chia, some fucking kale—modified the surge, and the bonk. Egg good, juice bad? O.K., then.

“Glucose variability can correlate with a variability in your subjective experience of mood,” Means said, though not in the way you’d think. The traditional notion of the sugar high, sugar crash doesn’t always bear out, to go by the overlay of verve and blood sugar. Once you have high levels of glucose in your system, the more you add, the less energy you feel; your cognitive-processing speed declines. The advantage of the glucose monitor, she said, is that it can reduce the misattribution of our subjective experiences—that habit we all have of telling ourselves, or especially other people, what might be causing certain symptoms or feelings. (“You’re just dehydrated.”) The wearables can help you tinker with the variables. It’s not so much the rush and the crash. It’s the roller coaster itself. Glucose excursions, or glycemic variability, which Means called “spikiness,” lead to oxidative stress (an imbalance between free radicals and antioxidants), which over time damages the mitochondria. (It’s the opposite of H.R.V., where spikiness is the goal, in a way.) And that, more than the sensation of the caffeine or the fructose wearing off, seems to be the true culprit, a leading cause of what Mark Hyman, the doctor and wellness celebrity, calls F.L.C. Syndrome—Feel Like Crap. “What’s happening in our cells is what’s happening in our bodies,” Means said.

By Means’s reckoning—and, admittedly, her perspective is not a rare one, in our desperate, fallen world—we are suffering from our own, twenty-first-century incarnation of George Miller Beard’s “American nervousness,” with less misogyny. We expect too much of ourselves, and then handicap our attempts to meet our expectations. There’s a contradiction: we need energy to do more, but to get it we need to do less, or at least less of the things we are doing. This particular energy crisis, to the extent that it is more metabolic than imagined, may be as apt an indicator of ill health, on a mass scale, as, say, addiction or disease.

“We like to think we have conscious control over our behavior, but the more we learn, the more we know that that’s not entirely true,” Kevin Hall, who runs a clinical-nutrition lab at the National Institutes of Health, in Bethesda, told me. “We’re less in control than we’d like.”

Hall has been trying to understand how different sources of energy in our diet affect metabolism—what happens, for example, when we restrict carbs or fat. “The body makes huge shifts to accommodate calories in different forms. You’re on a low-carb diet? The fat in your blood—triglycerides—stimulates the uptake and blocks the release of fat. Low-fat, high-starch? Insulin plays that role. The human body is like a vehicle that burns different fuels. It’s an incredible engineering challenge. The metabolism is a miraculous flex-fuel engine. Diesel, ethanol, doesn’t matter in the short term. It will adapt.”

A recent study published in the journal Current Biology determined that the body seems to adjust to higher burn rate by becoming more efficient, especially with exercise. This is called “energy compensation” and is not yet well understood. Generally, when your body burns through energy less efficiently, you are likely to die earlier and have a greater risk of disease. An inefficient metabolic system is like a car engine you rev too high: it wears out faster.

Richard Maurer comes from a family of long-distance runners. In college, he was obsessed with calories—what was and wasn’t working when he ran. The simple equation of calories in and out, the default presumption, didn’t actually seem to measure up. At the time, in the eighties, it was hard to find medical schools that taught nutrition (“Except the one in Loma Linda, and that was run by Seventh-day Adventists,” he said), so he wound up at the National College for Naturopathic Medicine, in Portland, Oregon. What was then fringe is now tacking sharply to mainstream.

“Every day we learn one thing less,” Maurer said. He cited a study of élite cyclists. They rode hard on a stationary bike and, when their muscles were spent, were given water on one occasion and a sweet drink like Gatorade on another, both of which they spit out without swallowing. The water spitters lagged behind, in terms of subsequent wattage produced. The taste of sugar had apparently tricked the brain into releasing energy that it had been hoarding for other functions. “In some ways, the bonk is a perception,” Maurer said.

In September, Sai Krupa Das, a scientist at the Jean Mayer U.S.D.A. Human Nutrition Research Center on Aging and a professor of nutrition at Tufts, sent me a Rand Corp. survey she and other clinicians use to get a sense of psychobiological energy. In one section, you are supposed to rate, on a scale of one to six, from “all of the time” to “none of the time,” your experience of the past four weeks:

Did you feel full of pep?
Have you been a very nervous person?
Have you felt so down in the dumps that nothing could cheer you up?
Have you felt calm and peaceful?
Did you have a lot of energy?
Have you felt downhearted and blue?
Did you feel worn out?
Have you been a happy person?
Did you feel tired?

All of the above? Is variability of mood more like H.R.V. or like blood sugar? It was hard to imagine a more subjective exercise. Das also sent me a link to the Web site of something called the Human Performance Institute, at Johnson & Johnson, which offered a survey that was a kind of screening for the “corporate athlete.” Who doesn’t love a self-evaluation? I aimed to be honest. The J. & J. verdict was that I was “disengaged”: “This suggests that significant obstacles stand in the way of fully igniting your talent and skill. To become an extraordinary performer, you must build significantly stronger energy management skills.” The corporate Olympics would have to go on without me.

Das didn’t have a test for the other kind of energy, the kind that one projects. “This kind of energy does exist, and people who have it generally do have that aura about them,” she said. “But it is certainly hard to measure. This energy is in large part physiological, too. There’s a genetic component, and a biological underpinning for cellular health that reflects in tissue health.”

Each day, I fixated on the data from my wearables, even as my resistance to change rendered them moot. I was more interested in adding exercise than in giving up my morning toast or evening whiskey. I sought the Whoop’s approval, if not that of its other evangelists. “I’ll invite you to join our group and help coach you,” Arnot wrote. “What’s your Whoop name?” Not telling. The Whoop’s version of what the Oura called “readiness” was “recovery,” also H.R.V.-based. For exercise, it emphasized “strain,” a more robust version of the Oura’s “activity” category. It rewarded a high heartbeat and a hard workout, and basically turned up its nose at long walks. It preferred sweat to steps.

And yet. The other day, an old friend passed through town from the Bay Area. We’d grown up across the street from each other and, in our fifth-grade production of “Alice in Wonderland,” had played Tweedledum and Tweedledee. We met up in Central Park, walked and talked for an hour—no secrets, at this age—and then said our fond farewells. I returned to the desk chair, energized.

That evening, I checked the data. The Oura ring, generous to a fault, gave me credit for burning two hundred and twenty-four calories. Ball don’t lie. The Whoop, though, had captured something else entirely. The readout from our meander suggested that I’d undergone my most gruelling physical trial not only since I got the device but in many years, possibly decades. It had me at nearly fifty minutes with an average heart rate above a hundred and fifty, plus twelve minutes above one-sixty-seven, with a high of one-eighty-five. Basically, according to the Whoop, I’d won the Tour de France and was now dead. Or the Whoop, for once, was mistaken: a glitch not in the matrix but in the watch.

Then there was a third possibility. My friend and I had had an excellent rapport on our stroll—a surge of groovy vibes and hearty laughter. Could this energy, the kind that is projected, perceived, and exchanged, yet purportedly impossible to measure, have somehow spun the monitor’s compass, like a poltergeist or a solar flare? Was my Whoop a spiritist? A line of Tweedledee’s came to mind: “Contrariwise, if it was so, it might be; and if it were so, it would be: but as it isn’t, it ain’t. That’s logic.” ♦