Then sometime in the middle decades -- perhaps as men hit their mid-30s and approach 40, or sometimes 50 -- the river changes. It no longer flows quite so smoothly, quite so fast. Knees give out during a squash game. Hair gives out, well, every time a comb runs through it. And men begin to think that, beyond the next bend, the end of the river waits. They can't see it yet, but they know that it's there.
This, for many men, marks a turning point, not just physically but in the mind as well.
"You realize half of your life is over," says screenwriter Bruce McKenna, 44, who just moved from Los Angeles to Santa Fe, N.M. "I found myself thinking seriously about what to do with the rest of it. I hit 42, 43, and I was more worried about my kids, about them growing up" -- his children are 13, 11 and 8 -- "about wanting to spend more time with them. I worried about working myself to an unhealthy degree, and I worried about finances. So I decided to leave L.A. Not only is Santa Fe cheaper, but L.A. is just not an easy town to be middle-aged in. In my business, you're old if you're 30."
Health, like so much else for men in midlife, is in flux, and men like McKenna are reacting to it. Bodies and mind-sets are changing. Physically, men pack on more pounds around the middle during these years, and report more chronic, nagging illnesses. At the same time, men increase their efforts to improve their well-being. Use of vitamins goes up, as does moderate and vigorous exercise, according to one of the largest studies ever done of middle age: a survey of 7,000 people called Midlife Development in the United States. The health portion of that survey was published in 2004 as a book, "How Healthy Are We?"
"We begin seeing our bodies start to deteriorate, and that's just a reality we have to cope with," says David Almeida, a psychologist at Pennsylvania State University and one of the study investigators.
But men at midlife actually seem well prepared to cope. Men in their 40s seem better able to "recalibrate" than do men in their 20s, says Almeida. They feel they can make adjustments and change for the better. They reach out to others more, and are less focused on themselves. In fact, men in midlife report fewer daily stresses than do women or younger men, according to the midlife development study.
The "midlife crisis" so often portrayed in the media -- a period of emotional tumult and strain, when men get divorced, buy a red Corvette, sleep with women half their age and get hair and pectoral implants -- is actually quite rare, researchers say. Instead, most men in their 40s are people like McKenna, adjusting to a changing situation with sensitivity and good judgment. "The midlife crisis notion is pretty much a dead duck," says Michael Kimmel, a sociologist at the State University of New York at Stony Brook and author of the book "Manhood in America." "It's a myth."
It certainly seems like a myth to Los Angeles resident Marty Sokol, 38, who produces reality shows for MTV and owns Club Chico, a nightspot in Montebello. "When you're in your 20s, you think a lot about what other people think of you. Now what's really important to me are my responsibilities to myself, to my employees, and to my community."
Sokol says he does a lot of things now that he wouldn't have dreamed about a decade ago. He meditates every day. He eats a healthful breakfast: granola, yogurt, flax and things high in antioxidants. "In my 20s that would more likely to have been an Egg McMuffin." He also exercises three times a week at a local gym, focusing on stretching more than strength-building.
For Thomas Henderson, 44, a former lab technician at the University of North Dakota in Grand Forks, family and fitness came together.
"Yeah, I started feeling a few more twinges, maybe some arthritis, maybe carpal tunnel coming on ... You start to wonder if these are harbingers of bigger problems," he says. "So I decided to start swimming." His two kids were in the Boy Scouts "and doing a lot of water activities. To supervise them, I needed to swim better myself. I started last year, and I was really a floundering beginner. Now I'm up to 1,000 yards a session, three or four times a week." He's still got a bit of a belly, "the ol' Buddha," but he doesn't obsess about it.
Henderson also made some other changes. He went back to school, starting a doctoral program in microbiology. Working in other people's labs, he was dependent on their ability to get grants. "But with a PhD I could get my own money for research, or a teaching position." That sense of flexibility and independence is important to him as he goes forward in life, he says, and it's important for his family.
This doesn't mean that every man at midlife is Mr. Maturity. "We probably all know someone who bought the little red sports car, dumped his wife, and all that," says Sam Cochran, a clinical psychologist at the University of Iowa and editor of the scientific journal Psychology of Men & Masculinity. "I just don't think there are that many of them." He does admit that when he goes to the gym "I see guys who are middle-aged and driving themselves too hard. They get kind of obsessive with the machines.... It's like they're trying to stop all the aging."
Adds McKenna: "One of the most terrifying things about getting older is fearing the loss of sexual potency. And all these magazines, like GQ, FM and Playboy, play off that fear." The glorification of youth, and linking it to celebrity and success, can give aging men the heebie-jeebies. "I have this one friend, a wealthy, powerful guy, and he's started driving a Ferrari, going to a lot of Vegas strip shows, and he's in the gym every morning at 6:30. I think he's kind of a joke."
But it's the minority who are driven to extremes by these worries. Only 10% of men are swirling in midlife turmoil, according to an estimate by psychologist Orville Brim, director of the midlife development study. The rest are following the river, trying to stay out of the rocks and enjoying the ride.