Exercise turns out to be the closest thing to a wonder drug that self-control scientists have discovered.

Heart rate variability is such a good index of willpower that you can use it to predict who will resist temptation, and who will give in.

Heart rate goes up, and variability goes down. The heart gets “stuck” at a higher rate—contributing to the physical feelings of anxiety or anger that accompany the fight-or-flight response. In contrast, when people successfully exert self-control, the parasympathetic nervous system steps in to calm stress and control impulsive action. Heart rate go

When people are under stress, the sympathetic nervous system takes over, which is part of the basic biology that helps you fight or flee.

Your heart speeds up a bit when you inhale: buh-dum buh-dum buh-dum. It slows down again when you exhale: buh-dum buh-dum buh-dum. This is good. This is healthy. It means that your heart is getting signals from both branches of your autonomic nervous system: the sympathetic nervous system, which revs the body into action, and the parasympathetic ne

The single best physiological measurement of the pause-and-plan response is something called heart rate variability—a

The goal is not to paralyze you in the face of internal conflict, but to give you freedom. By

Instead of speeding up, your heart slows down, and your blood pressure stays normal. Instead of hyperventilating like a madman, you take a deep breath. Instead of tensing muscles to prime them for action, your body relaxes a little.

To help the prefrontal cortex, the pause-and-plan response redirects energy from the body to the brain.