Spark: The Revolutionary New Science of Exercise and the Brain

by John J. Ratey

It turns out that moving our muscles produces proteins that travel through the bloodstream and into the brain, where they play pivotal roles in the mechanisms of our highest thought processes.

brain-derived neurotrophic factor (BDNF). Whereas neurotransmitters carry out signaling, neurotrophins such as BDNF build and maintain the cell circuitry—the infrastructure itself.

Learning requires strengthening the affinity between neurons through a dynamic mechanism called long-term potentiation (LTP).

But guess what? They do grow back—by the thousands. Not until scientists became handy with advanced imaging tools that enabled them to peer into the brain did they find conclusive evidence, which was published in a seminal 1998 paper. It came from an unlikely source. Cancer patients are sometimes injected with a dye that shows up in proliferating cells so that the spread of the disease can be tracked. Researchers looked at the brains of terminally ill patients who had donated their bodies to science and found that their hippocampi were packed with the dye marker, proof that neurons were dividing and propagating—a process called neurogenesis—just like cells in the rest of the body. With that, they formalized one of the biggest discoveries in neuroscience.

Exercise spawns neurons, and the stimulation of environmental enrichment helps those cells survive.

During exercise, BDNF helps the brain increase the uptake of IGF-1, and it activates neurons to produce the signaling neurotransmitters, serotonin and glutamate. It then spurs the production of more BDNF receptors, beefing up connections to solidify memories. In particular, BDNF seems to be important for long-term memories.

VEGF gets to work building more capillaries in the body and the brain. Researchers suspect that one way VEGF is vital to neurogenesis is its role in changing the permeability of the blood-brain barrier, prying back the fence to let other factors through during exercise.

Now you know how exercise improves learning on three levels: first, it optimizes your mind-set to improve alertness, attention, and motivation; second, it prepares and encourages nerve cells to bind to one another, which is the cellular basis for logging in new information; and third, it spurs the development of new nerve cells from stem cells in the hippocampus.

Cognitive flexibility is an important executive function that reflects our ability to shift thinking and to produce a steady flow of creative thoughts and answers as opposed to a regurgitation of the usual responses. The trait correlates with high-performance levels in intellectually demanding jobs. So if you have an important afternoon brainstorming session scheduled, going for a short, intense run during lunchtime is a smart idea.

Learning the asanas of yoga, the positions of ballet, the skills of gymnastics, the elements of figure skating, the contortions of Pilates, the forms of karate—all these practices engage nerve cells throughout the brain. Studies of dancers, for example, show that moving to an irregular rhythm versus a regular one improves brain plasticity. Because the skills involved in these activities are unnatural forms of movement, they serve as activity-dependent learning of the sort that made Hebb’s rats smarter and that Greenough showed made synapses bushier.

Nobody else is around, and they feel safe in his presence. He has already determined how far they can sprint before coming to exhaustion, and—this is the clever part—Johnsgard marks off that distance from the main door of the mall, and then has them sprint from his side toward the mall. The idea is that they reach the height of their fear in a state of full physical arousal, without the panic. If they feel a panic attack coming on, they are instructed to stop, turn, and walk back to him. They run toward fear and walk toward safety.

One of the hurdles to conquering depression is that the disorder encompasses such a broad array of symptoms, most of which all of us experience at some point. Who doesn’t feel grouchy, irritable, pessimistic, lethargic, apathetic, self-critical, or melancholy on occasion?

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 and sends you looking for more alcohol. That’s how a problem at work or a fight with a lover can cause a relapse.

What she did was get an indoor bike trainer of the type used by serious cyclists to hone their balance and stamina—you pedal on free-spinning drums, acutely aware of the possibility that you could slip off and careen across the room. I’m not sure how Zoe settled on this extremely challenging form of exercise, but it has worked out tremendously well. The balance and precision required to ride on the rollers engages the entire attention system, from the motor centers of the cerebellum and basal ganglia to the reward center and prefrontal cortex. “At first I hated to do it because it doesn’t bring you anywhere,” she says. “Now I’m very handy on it, and it’s beneficial because it makes me concentrate as well as exercise. It’s exciting because you don’t want to fall down.”

For someone with a negative body image, shifting the focus from the body to the brain can provide a powerful new sense of motivation.

Good phrase

In fact, there was no opponent. All of the participants were subjected to the noise—which kept getting louder—half of the time. As the volume increased, the women with depleted tryptophan aggressively cranked up the volume, lashing out at their imaginary opponent. The study concluded that lowering the precursor to serotonin in healthy women increases their tendency toward aggressiveness. “They were much more likely to retaliate than women with normal levels of serotonin,” says Alyson Bond, who conducted the study. “They behaved in a similar way to habitually aggressive people.”

The major implication is that exercise not only keeps the brain from rotting, but it also reverses the cell deterioration associated with aging. More than likely, what Kramer’s scans show is how exercise improves the brain’s ability to compensate. “Let’s say the prefrontal cortex isn’t functioning quite up to par,” he explains. “You might be able to recruit other areas of the cortex to do the task in a different way. One way to think about the increased volume is that it might turn back the clock in terms of how well the circuits function to do different things.”

This really underscores the idea that if you’re not busy living, your body will be busy dying.

Interesting

“An idle mind is the devil’s workshop.”

diet, exercise, and staying mentally active.

As for what you do eat, there are certain foods that activate cellular repair mechanisms, as I mentioned in chapter 3. Cumin, garlic, onions, and broccoli, for instance, all contain toxins meant to keep pests at bay, but the levels are low enough that they trigger a beneficial stress response. The same holds true for free radical–fighting foods such as blueberries, pomegranates, spinach, and beets—it’s the toxins as well as the antioxidants that ultimately lead to cellular repair. Green tea and red wine are beneficial in the same way.

You can find omega-3s in deep-water fish such as salmon, cod, and tuna, or you can take a daily supplement that contains 1200 mg of eicosapentaenoic acid (EPA) and 200 mg of docosahexaenoic acid (DHA)—the two key omegas. Vitamin D is being recognized not only for its importance in strengthening bones but also as a measure against cancer and Parkinson’s. I would recommend 1000 IU (international units) of vitamin D and for women, 1500 mg of calcium. I would also recommend taking vitamin B with at least 800 mg of folate, which improves memory and processing speed.

In his book Racing the Antelope: What Animals Can Teach Us about Running and Life, biologist Bernd Heinrich describes the human species as an endurance predator. The genes that govern our bodies today evolved hundreds of thousands of years ago, when we were in constant motion, either foraging for food or chasing antelope for hours and days across the plains. Heinrich describes how, even though antelope are among the fastest mammals, our ancestors were able to hunt them down by driving them to exhaustion—keeping on their tails until they had no energy left to escape. Antelope are sprinters, but their metabolism doesn’t allow them to go and go and go. Ours does. And we have a fairly balanced distribution of fast-twitch and slow-twitch muscle fibers, so even after ranging miles over the landscape we retain the metabolic capacity to sprint in short bursts to make the kill. Today, of course, there’s no need to forage and hunt to survive. Yet our genes are coded for this activity, and our brains are meant to direct it. Take that activity away, and you’re disrupting a delicate biological balance that has been fine-tuned over half a million years. Quite simply, we need to engage our endurance metabolism to keep our bodies and brains in optimum condition. The ancient rhythms of activity ingrained in our DNA translate roughly to the varied intensity of walking, jogging, running, and sprinting. In broad strokes, then, I think the best advice is to follow our ancestors’ routine: walk ...