“Exercise has a direct brain connection, when you consider what it actually does. What we tend to overlook are the feedback loops that connect the brain to every cell in the body. Therefore when you throw a ball, run on a treadmill, or jog along the shore, billions of cells are "seeing" the outside world. The chemicals transmitted form the brain are acting the way sense organs do, making contact with the outside world and offering stimulation from that world.This is why the jump from being sedentary to doing a minimal amount of exercise - such as walking, light gardening, and climbing the stairs instead of taking the elevator - is so healthy. Your cells want to be part of the world.”

“Barry L. Jacobs and colleagues from the neuroscience program at Princeton University showed that when mice ran every day on an exercise wheel, they developed more brain cells and they learned faster than sedentary controls. I believe in mice.”

“God has given us more than fourteen billion cells and connections in our brain. Why would God give us such a complex organ system unless he expects us to use it?”

“The tragedy is that every brain cell devoted to belief in the supernatural is a brain cell one cannot use to make life richer or easier or happier.”

“Courage is about learning how to function despite the fear, to put aside your instincts to run or give in completely to the anger born from fear. Courage is about using your brain and your heart when every cell of your body is screaming at your to fight or flee - and then following through on what you believe is the right thing to do.”

“When cells are no longer needed, they die with what can only be called great dignity. They take down all the struts and buttresses that hold them together and quietly devour their component parts. The process is known as apoptosis or programmed cell death. Every day billions of your cells die for your benefit and billions of others clean up the mess. Cells can also die violently- for instance, when infected- but mostly they die because they are told to. Indeed, if not told to live- if not given some kind of active instruction from another cell- cells automatically kill themselves. Cells need a lot of reassurance. When, as occasionally happens, a cell fails to expire in the prescribed manner, but rather begins to divide and proliferate wildly, we call the result cancer. Cancer cells are really just confused cells. Cells make this mistake fairly regularly, but the body has elaborate mechanisms for dealing with it. It is only very rarely that the process spirals out of control. On average, humans suffer one fatal malignancy for each 100 million billion cell divisions. Cancer is bad luck in every possible sense of the term.”