WE ARE ALL born physically and mentally soft. A baby zebra can get up and run on the Serengeti plains fifteen minutes after birth. It takes us more than a year to do the same. Most of us live in a country and grow up in families that afford us the luxury that when we are hot, we turn on an air conditioner, and when we are cold, we turn on a heater. That is not the case in most parts of the world. It just happens to be the case where we live, and for those fortunate enough to have the financial ability, where we vacation. We are born physically and mentally soft, and many of us remain soft throughout our lives. Then, so long as we have talent, we still do well. Many people do. However, to do great, to summit Mount Everest, or achieve whatever goals we set for ourselves, we must get comfortable being uncomfortable. We must inoculate against stress.

Mentally tough people understand that the more adversity they face, the greater their toughness. Just as every fall we get a flu shot—a small dose of the flu that helps our immune systems against the greater virus—we must do the same with stressful situations and adversity. We must find ways to inoculate ourselves against both. To do so, we must get comfortable being uncomfortable. We must get outside our comfort zone. If you find public speaking stressful, then take a public speaking course that forces you to speak in front of large groups. If making a cold call stresses you out, make a cold call. If a group fitness class frightens you or makes you uncomfortable, go take one. By doing so, we gain confidence, and because we gain confidence, we feel decreased levels of stress.

Therefore, in moments that many people might feel are extremely stressful, mentally tough people, who have stress-inoculated themselves, simply won’t feel the same level of stress as those who haven’t. They don’t have to be incredibly mentally tough in those situations that others find extremely adverse or stressful, because they find the same situation much less so.

As discussed earlier, after every Marine Corps (and most military) operations, units conduct a full debrief of the operation. At one, a pilot was telling another member of his squadron how everything was “screwed up” with the refueling of the aircraft and how the corresponding stress of it caused major issues for him. His teammate stopped him in midsentence and said, “That wasn’t stressful! If you want to know stress, come to my house for dinner tonight and eat with my wife and eight kids. Then you will know stress!”

Dinner every night with his eight children had stress-inoculated that pilot so that his airplane not being refueled was just not that stressful. He was still able to stay aware of the environment and accomplish the mission. He was mentally tough. Admittedly, both pilots are probably mentally tough people. To do what they do requires it. However, when planes weren’t being refueled, the pilot who stress-inoculated himself at dinner every night didn’t require as much mental toughness as the pilot who hadn’t.

This is true for all of us. We must stress-inoculate ourselves. If we don’t have eight children all under the age of twelve, we must seek out adverse situations that force us outside of our comfort zone. Doing so increases our confidence and lessens the level of stress we feel when faced with adversity in the future. Like the pilot who’s the father of eight children, we won’t need to draw on great stores of mental toughness because we won’t find the stressful situation that stressful.