Spark: The Revolutionary New Science of Exercise and the Brain

by John J. Ratey

getting to the gym, to keep from stewing in the trauma.

By activating the sympathetic nervous system through exercise, you break free from the trap of passively waiting and worrying, and thus prevent the amygdala from running wild and reinforcing the danger-filled view of what life is presenting.

You’re improving alternate connections, actively learning an alternative reality.

You learn that you can be effective in controlling anxiety without letting it turn into panic. The psychological term is self-mastery, and developing it is a powerful prophylactic against anxiety sensitivity and against depression, which can develop from anxiety.

In fact, all that most chronically anxious people want is not to be anxious.

two-thirds of the cases the problem started as preadolescent anxiety. What’s tragic here is that anxiety is relatively easy to treat, but it often goes undiagnosed in children—the anxious kids are sitting quietly at the back of the class, terrified. Nobody notices there is something wrong because these kids are well behaved. Meanwhile, the anxiety is wearing in negative patterns in their brains that can become entrenched and set these kids up for future problems.

Home visits

nobody really knows whether exercise can entirely replace medication. Our brains are just too complex.

The farther they get from their last panic episode, the less likely they are to have another panic episode. The same holds true for any brand and any degree of anxiety. The more your life changes, the more you engage with the world, the more likely you are to put the anxiety behind you for good. Exercise can have an even more dramatic effect on milder anxiety, the kind that isn’t bad enough for medication but is still troublesome.

physical activity alone helped tremendously, both in the moment and day to day, and it cleared the way for talk therapy to get at the underlying issues.

The court battle may continue for years, but she’s no longer overwhelmed by it, and exercise has been her best defense.

Depressing

antihistamine produced similar mood-elevating effects and spawned a class of drugs called tricyclic antidepressants.

exercise does for the brain. It counteracts depression at almost every level.

In Britain, doctors now use exercise as a first-line treatment for depression, but it’s vastly underutilized in the United States, and that’s a shame. According to the World Health Organization, depression is the leading cause of disability in the United States and Canada, ahead of coronary heart disease, any given cancer, and AIDS. About 17 percent of American adults experience depression at some point in their lives, to the tune of $26.1 billion in health care costs each year. It’s impossible to know how many people try to commit suicide, but, tragically, in the United States someone succeeds about every seventeen minutes. For this reason, and also because 74 percent of depression patients experience some other disorder—including anxiety, substance abuse, and dementia—it’s an urgent problem.

Two years later, I was off to medical school at the University of Pittsburgh, where I started my own daily psychoanalysis and steeped myself in the emerging brain science. Everyone at Pitt was already working on MHPG, so I settled for measuring lithium uptake into red blood cells as a possible way of identifying different mood problems. I also froze urine samples of patients with schizophrenia, which were then sent off to Linus Pauling at Stanford; learned how to program computers to conduct data analysis; and presented findings at a psychophysiology conference. Through my research, I was utterly caught up in the passion of trying to make psychiatry a “real” science.

Pitt

Dopamine is all about motivation and attention. Studies have shown that chronic exercise increases dopamine storage in the brain and also triggers the production of enzymes that create dopamine receptors in the reward center of the brain, and this provides a feeling of satisfaction when we have accomplished something. If the demand is there, the dopamine genes get activated to produce more, and the overall effect is a more stable regulation of these pathways, which are important to controlling addictions.

The MRI scans pointed toward a radical notion: that chronic depression may cause structural damage in the thinking brain.

The shutdown in depression is a shutdown of learning at the cellular level. Not only is the brain locked into a negative loop of self-hate, but it also loses the flexibility to work its way out of the hole. Redefining depression as a connectivity issue helps explain the wide range of symptoms people experience. It’s not just a matter of feeling empty, helpless, and hopeless. It affects learning, attention, energy, and motivation—disparate systems that involve different parts of the thinking brain.

Depression also affects the body, shutting down the drive to sleep, eat, have sex, and generally look after ourselves on a primitive level.

Ironically, I think this is precisely why exercise has yet to be embraced as a medical treatment. It doesn’t simply raise serotonin or dopamine or norepinephrine. It adjusts all of them, to levels that, we can only presume, have been optimally programmed by evolution. The same goes for exercise’s effect on BDNF, IGF-1, VEGF, and FGF-2, which provide the building material and oversight for the construction of new connections and neurons.

ADHD stems from a malfunction of the brain’s attention system, a diffuse linkage of neurons that hitches together areas controlling arousal, motivation, reward, executive function, and movement. Let’s take one element of the attention system: motivation. While it’s true that people with ADHD “just need to get motivated,” it’s also true that, like every other aspect of our psychology, motivation is biological. What about the child who can’t pay attention in class but can sit perfectly still for hours playing a video game?

I tell my patients a more helpful way to think of ADHD is as an attention variability disorder; the deficit is one of consistency.

Experts estimate that just over 4 percent of American adults—that’s thirteen million people—have ADHD, which is not to say that the remaining 96 percent of the population is completely free of attention problems.

shaking their legs, doodling, fiddling.

often adopt the role of class clown if they’re having trouble with school.

Many of them are socially adept,

People with ADHD will do anything not to stand in line and can explode if they’re made to wait.

Paradoxically, one of the best treatment strategies for ADHD involves establishing extremely rigid structure. Over the years, I’ve heard countless parents offer the same observation about their ADHD children: Johnny is so much better when he’s doing tae kwon do. He wasn’t doing his homework, and he was angry, difficult, and problematic; now his best qualities have come out.

the amygdala is responsible for assigning emotional intensity to incoming stimuli before we’re conscious of it, and then sends it along for higher processing. In the context of ADHD, the amygdala determines the “noticeableness” of things. An unregulated amygdala is what feeds the tantrums or blind aggression in patients with ADHD, and their oversensitivity to excitement can lead to panic attacks. Sometimes excitability is a positive—people with ADHD can get so enthusiastic about something that they energize a roomful of people. (Holding the attention of others is no problem for those with ADHD.)

Dopamine also carries signals to the nucleus accumbens, or reward center, which is where Ritalin, amphetamine-dextroamphetamine (Adderall), and the active agents of other stimulants—from coffee to chocolate to cocaine—end up. The reward center needs to be sufficiently activated before it will carry out its important duty of telling the prefrontal cortex that something is worth paying attention to. It engages the prioritizing aspect of executive function, and this is a central component of motivation.

Dopamine works like transmission fluid: if there’s not enough, as is the case in people with ADHD, attention can’t easily be shifted or can only be shifted all the way into high gear.

ADHD is a huge but largely undiagnosed issue for the reservation kids because the incidence of the disorder among Apaches seems to be much higher than for the general population.

These are the rare, worst-case examples of what can happen to people who completely lose control of their behavior. And while the lives of those addicted to hard drugs such as crack or heroin or crystal meth look drastically different than the lives of those who use or abuse drugs without being hooked, the same principles apply to their brains. Which is to say that the lessons of Odyssey House apply to anyone who struggles with self-control, including those who think of themselves as having addictive personalities. Scientists are now characterizing behavior such as gambling, compulsive shopping, and even overeating in the same biological terms they use to explain substance abuse. The common denominator is an out-of-control reward system, which some people are born with and some people develop.

All the things people become addicted to—alcohol, caffeine, nicotine, drugs, sex, carbohydrates, gambling, playing video games, shopping, living on the edge—boost the dopamine in the nucleus accumbens.

“Dopamine is involved in this wanting, but it’s not involved in liking.”

the very core systems that have evolved to mediate survival,” says Robinson. “They activate the system in ways it was never meant to be activated.” The National Institute on Drug Abuse now defines addiction as a compulsion that persists in spite of negative health and social consequences.

We know from studies in animals and humans that cocaine, for one, damages nerve cells in the prefrontal cortex and even reduces gray matter.

who used her jump rope to fend off the stress-induced urge to drink wine in the middle of the day. The biology of stress ties in with addiction in that withdrawal puts the body in survival mode. If you suddenly quit drinking, for instance, you’re turning off the dopamine spigot and the hypothalamic-pituitary-adrenal axis gets thrown out of balance. The intense unpleasantness of withdrawal lasts for only a few days, but your system remains sensitive for much longer. If you’re in this delicate state and come under further stress, your brain interprets the situation as an emergency

left her

A NATURAL HIGH Some would debate whether Zoe was addicted to marijuana, but there’s no question she was dependent on it. She had all the signs of chemical dependency, including the physical and emotional irritability of withdrawal. Studies in rats show that if they get used to a chronic dose of tetrahydrocannabinol (THC)—the active compound in marijuana—and then are deprived of it, the brain floods the system with corticotropin-releasing factor, which activates the amygdala and thus the entire stress system. The rodents experience shaking, tremors, and twitchy movements that peak about forty-eight hours after the last dose. Indeed, Zoe felt like a rat in a cage when she went through detox: along with the physical symptoms, the shutdown of the dopamine system brought on intense feelings of depression and anxiety. The way exercise blunts the symptoms of withdrawal is by calming the amygdala and boosting dopamine.

We’ve been on the case of the runner’s high for three decades, and in the last few years the focus has expanded beyond endorphins to include endocannabinoids, a class of neurotransmitters. Endocannabinoids are to THC as endorphins are to morphine—substances produced in the body that elicit the same effect as a drug. Likewise, they both dull pain.

THC binds to specialized receptors in the brain. These receptors didn’t evolve for us to enjoy marijuana, obviously, so there had to be some natural substance the body produces for them. What they found were the neurotransmitters anandamide and 2-arachidonoylglycerol (2-AG). It turns out that marijuana, exercise, and chocolate all activate these same receptors in the brain.

Dean Karnazes, the forty-four-year-old Californian who has appeared on 60 Minutes, The Tonight Show, and countless magazine covers for his mind-bending feat of running fifty marathons in fifty days (in fifty different states). He also ran 350 miles without stopping. Only slightly less impressive to me is that over the past fifteen years, the longest period he has gone without exercising is three days. “I had the flu,” Karnazes recalls. “I was still sick, but I finally said, Screw it, I need to bust out a run.” For starters, his streak says something about the formidable strength of his immune system.

How much exercise you need depends, of course, on how severe the habit is. But I would say thirty minutes of vigorous aerobic exercise five days a week is the bare minimum if you want to root out an addiction.

A lot of people assume that an addict’s real problem is just a lack of motivation. On one level, this is true, but what very few people recognize is that motivation is a function of brain signals, and that those signals depend on reliable messengers and intact nerve pathways. When we look at addiction as a neurological malfunction rather than as a moral failure, it suddenly takes on the form of something that can be fixed. It’s certainly not an easy task, but it’s a lot easier when we use exercise as a tool, one with great versatility.

! Home visits Framing a crisis

Exercise is particularly important for women because it tones down the negative consequences of hormonal changes that some experience, and for others, it enhances the positive. Overall, exercise balances the system, on a monthly basis as well as during each stage of life, including pregnancy and menopause.

The average woman has four hundred to five hundred menstrual cycles in her lifetime, each one lasting four to seven days. If you add them all up, it comes out to more than nine years—a long time for women who suffer premenstrual syndrome (PMS).

The subject was hotly debated by the medical experts who decide what should be included in the Diagnostic and Statistical Manual and what each condition should be called. PMS has been renamed in various editions of the DSM, and in 1994 the entry was changed from the inscrutable late luteal phase dysphoric disorder (LLPDD) to premenstrual dysphoric disorder (PMDD).

gonadotropins,

They found that the brains of women with the diagnosis had an impaired ability to “trap” tryptophan in the prefrontal cortex, thus limiting the production of serotonin, which helps regulate mood and behavior such as angry outbursts.

“It’s almost like I’m in a fog before my period,” she says. “I could take my ADHD medication, and it won’t do a damn thing. Exercise helps clear my head.”