Dr. John Ratey, co-author of the ground-breaking ADD/ADHD book, Driven to Distraction, presents evidence in SPARK that exercise tempers these disorders
Regular exercise can raise levels of dopamine and norepinephrine, and improve functioning of brain systems that regulate impulse, memory and attention
It’s easy to get distracted in today’s world. It’s become so full of information, noise, and interruptions that all of us feel overwhelmed and unfocused at times. The amount of data in the world is doubling every few years, but, according to Dr. John Ratey, our attention system, like the rest of the brain, was built to make sense of the surrounding environment as it existed ten thousand years ago.
The attention system doesn’t claim a central address in the brain. Rather, it’s a diffuse web of reciprocal pathways that begins at the locus coeruleus, the arousal center, a part of the brain stem, and sends signals throughout the brain to wake it up and cue our attention. The network engages such areas as the reward center, the limbic system, and the cortex; more recently scientists have included the cerebellum, which governs balance and fluidity. It turns out that there’s a lot of overlap between attention, consciousness, and movement.
Exercise raises the baseline levels of dopamine and norepinephrine
The attention circuits are jointly regulated by the neurotransmitters norepinephrine and dopamine, which are so similar on a molecular level that they can plug into each others’ receptors. These are the chemicals targeted by ADHD medications. And of the many genes correlated with the disorder, scientists focus on the ones that regulate these two neurotransmitters. Broadly speaking, the problem for people with ADHD is that their attention system is patchy; they describe it as discontinuous, fragmented, and uncoordinated — problems that can stem from a dysfunction with either of these neurotransmitters or in any one of the brain areas in the system.
The good news is that with regular exercise we can raise the baseline levels of dopamine and norepinephrine by spurring the growth of new receptors in certain brain areas, notes Dr. Ratey in his book SPARK. In the brain stem, balancing norepinephrine in the arousal center also helps.
The prefrontal cortex also bears responsibility for ADHD and again, studies have shown that exercise has a positive influence on the functioning of this area as well. The prefrontal cortex is the home of working memory, which sustains attention during a delay for a reward, and holds multiple issues in the mind at once. If working memory is impaired, we can’t stay on task or work toward a long- term goal because we can’t keep an idea in mind long enough to operate on it or to ponder, process, sequence, plan, rehearse, and evaluate consequences.
The relationship between movement and attention
It’s not simply a matter of whether the signals get through to capture our attention, but how fluidly that information travels. This is where the attention system ties in with movement and thus exercise: the areas of the brain that control physical movement also coordinate the flow of information.
The cerebellum is a primitive part of the brain that for decades was assumed to be involved only with governing and refining movement. When we learn how to do something physical, whether it’s a karate kick or snapping our fingers, the cerebellum is hard at work. The cerebellum takes up just 10 percent of the brain’s volume, but it contains half of our neurons, which means it’s a densely packed area constantly buzzing with activity. But it keeps rhythm for more than just motor movements: it regulates certain brain systems so they run smoothly, updating and managing the flow of information to keep it moving seamlessly. In patients with ADHD, parts of the cerebellum are smaller in volume and don’t function properly, so it makes sense that this could cause disjointed attention.
Exercise tempers ADHD is by immediately increasing the neurotransmitters dopamine and norepinephrine. When we exercise, particularly if the exercise requires complex motor movement, we’re also exercising the areas of the brain involved in the full suite of cognitive functions. We’re causing the brain to fire signals along the same network of cells, which solidifies their connections.