When we go for a walk, the heart pumps faster, circulating more blood and oxygen not just to the muscles but to all the organs—including the brain. Many experiments have shown that after or during exercise, even very mild exertion, people perform better on tests of memory and attention. Walking on a regular basis also promotes new connections between brain cells, staves off the usual withering of brain tissue that comes with age, increases the volume of the hippocampus (a brain region crucial for memory), and elevates levels of molecules that both stimulate the growth of new neurons and transmit messages between them.
Because we don’t have to devote much conscious effort to the act of walking, our attention is free to wander—to overlay the world before us with a parade of images from the mind’s theatre. This is precisely the kind of mental state that studies have linked to innovative ideas and strokes of insight.
If you look at parts of the world where people live the longest, they aren’t doing intense daily cardio workouts, running or cycling countless miles, or attending bootcamps. They simply walk, stand, bend and squat more throughout the day, and do much of it outdoors. Nearly all of the health risks I see in my patients can be improved by walking more steps. Studies show that walking lowers blood sugar and triglycerides after meals, lowers inflammation, modestly lowers body fat, lowers stress and improves immunity, prevents falls in the elderly and increases longevity.