One of the most wonderful things about being in midlife today is the sheer time it leaves us to reflect upon, adjust, or change our lives. In the year 1800, life expectancy for an American man was thirty-five years.

In 1900, the average life expectancy was forty-six years.

In 1950, it was sixty-nine.

Today, the average life expectancy for a man is seventy-six years old. So you literally could say that seventy-six is the new thirty-five.

Besides reminding us that we have much to be grateful for, these facts show that those of us who are actually in midlife are going through something that's truly unprecedented. Never in history have so many people at one time had to deal with what it really means to be, say, forty-five years old and know that you might very well still have half your life ahead of you. The uniqueness of that situation sheds light on the reason so many of us don't feel anywhere near as old as our chronological age. In fact, the other day, when I was speaking to a group of "twentys," I told them what fun it was for me to speak to people who are the same age as I feel. They laughed (the whippersnappers), but it was completely true.

Our feeling that way makes perfect sense, doesn't it? Because the model that we have in our heads of what it means to be fifty years old is the people our parents were—or, worse, the people their parents were—when they were fifty.

Our parents at fifty seemed a lot older than we feel at fifty. And I don't think it's just because men's hair was oiled and women's ratted—or that any of their wardrobes would be featured today on What Not to Wear. No, they seemed older because in every physical way our parents were older at fifty than we are or will be at the same age. And we know that's true because we know that overall their generation's life expectancy is lower than ours. (And they were modeling their midlife on what our grandparents were like at forty-five or fifty. To our parents, forty-five or fifty meant you were truly old.)

At fifty, I felt like I was just getting started—and I still feel that way today. And with a one-year-old, that's a very good thing indeed.

The bottom line is that by every possible measure we are simply not as physically or mentally aged as our parents or grandparents were when they were as old as we are now.

It's more than just a cliché. Sixty really is the new fifty. Fifty really is the new forty—and forty really is the new thirty.

And that means that all of us who are middle-aged today really are (whether boldly or not) going where no man has ever gone before.

And that can be a little disorienting.

Each man going through midlife right now will respond to that extremely personal journey in a way unique to himself. For some guys, midlife means watching their diet and joining a gym. For others, it means shaving their head, getting a tattoo, and trying to join their nephew's college fraternity. For some it becomes a time for "performance enhancing drugs" such as Viagra and Cialis. (I thank God for the advances in pharmacology such as these—well, and of course for those that do so much to fight other conditions, such as diabetes and psoriasis.) Most of us take the simpler route to midlife: We just start losing our hair and try to prevent parting what's left of it in a circle, or start combing it with a washcloth with the use of a "follicle enhancing" drug like Propecia or Rogaine.