The Brain’s Stress Switch: Why We Procrastinate, Crave Crises, and Need Exercise

Alert Mode: Norepinephrine and Dopamine in Action
Your brain relies on two key neurotransmitters to snap into focus: norepinephrine first arouses attention, then dopamine sharpens and hones it. In people with ADHD, an imbalance here creates “stress junkies”—they need stress to concentrate. This drives procrastination: they wait until a deadline looms like the Sword of Damocles, unleashing norepinephrine and dopamine to finally tackle the work.

This need for pressure also explains self-sabotage. When life runs smoothly, ADHD brains stir up crises subconsciously, shooting themselves in the foot just to fuel focus.

The Stress Response: Epinephrine and Cortisol Team Up
Stress kicks off with epinephrine, which quickly converts glycogen and fatty acids into glucose to power muscles and brain. Cortisol follows more slowly through the bloodstream, acting as a metabolic traffic cop.

Cortisol signals the liver to release more glucose, blocks insulin in nonessential tissues, and makes the body insulin-resistant—ensuring fuel flows to fight-or-flight needs. It restocks energy by turning protein into glycogen and storing fat. Cortisol also triggers insulin-like growth factor (IGF-1) to fuel cells.

The brain guzzles 20% of the body’s glucose despite being just 3% of body weight, with no storage capacity. Cortisol keeps this steady supply flowing, but chronic stress starves thinking regions as the HPA axis hogs fuel.

Cortisol’s Double Edge on Memory
Cortisol isn’t all good or bad. A little strengthens memories; too much suppresses them; overload erodes neuron connections.

The hippocampus adds context (what, where, when) to memories, while the amygdala layers emotion (fear, excitement). Guided by the prefrontal cortex, the hippocampus calms the HPA axis—like recognizing a stick, not a snake.

Stress agents (cortisol, CRE, norepinephrine) bind receptors, boosting glutamate for faster hippocampal signaling. This enhances long-term potentiation (LTP), memory’s core mechanism, and builds proteins for bigger dendrites and synapses—cementing survival memories.

But excess cortisol blocks new, unrelated memories and access to old ones. That’s why panic makes you forget the fire exit—lines go down.

Modern Life vs. Stone Age Genes
Our ancestors burned far more energy: over 38% more per body mass than us, walking 5-10 miles daily just to eat. Today, even 30 minutes of exercise falls short of our genetic blueprint. Calorie intake has risen, but energy output plummets—we stockpile fat at desks because thrifty genes expect scarcity.

This mismatch evolved over millennia; our century of abundance hasn’t caught up.

Exercise: The Ultimate Repair Tool
Like muscles, neurons grow stronger through mild stress and recovery. Exercise breaks down tissues then activates repair, boosting resilience in body and brain. It sharpens adaptability, quick thinking, and stress handling—bridging our genes to modern life.

Source : Spark: The Revolutionary New Science of Exercise and the Brain byJohn J. Ratey,Eric Hagerman

Goodreads :https://www.goodreads.com/book/show/721609.Spark

Read the Previous Article in the Series :