Frederick Brown wakes up at 7 a.m. - eager, alert and ready to go.
His wife, Cynthia LaJambe, on the other hand, is a classic night owl.
"You've heard of the night owls and the larks, I imagine? The larks twitter in the morning and drive the owls crazy," he says.
"So when I finish the morning paper, my wife comes down, and she's going for her coffee and I'm trying to say, 'Hey, you know what's in the paper this morning?,' she says, 'Not interested.' At night when I'm getting ready for bed, she says, 'You know, I found an interesting research article that you might want to consider,' and I say, 'Wait, no. I'm slowing down. I'm ready for bed.'"
The owl-lark mismatch doesn't get much attention in romantic comedies and online dating profiles, but maybe it should.
While some people in established relationships, including Brown, an associate psychology professor at Penn State University, sing the praises of owl-lark love, morning birds and night owls who are just starting to date should recognize that they really are out of sync in a significant way, according to Susan Krauss Whitbourne, a psychology professor at the University of Massachusetts at Amherst.
"Most people joke around about that, but they don't really take it seriously," says Whitbourne, who says that mismatched sleep schedules are a legitimate deal breaker for some new couples.
For those who decide to proceed, she recommends openly acknowledging the issue, telling your significant other when the timing of shared activities isn't working for you, and working out couple times that are good for both of you.
"It's like finances, or family, or taste in movies - it's one of those areas that couples have to negotiate," Whitbourne says.
Brown, a sleep researcher who, together with LaJambe, has collected 20,000 surveys on morning and evening sleep patterns, says that about 25 percent of Americans are moderate to extreme morning people and about 25 percent are moderate to extreme night people. The remaining 50 percent are in the more flexible "day type" category.
Brown advises new lark-owl couples to allow night people to be night people and vice versa.
He and his wife have a pact to not talk to each other the first and last hour or two of the day, and he says he doesn't miss her during their out-of-sync times.
"We have such full lives, and we enjoy each other so much (when we're together)," he says.
Brown suspects it isn't easy to change your schedule for someone with the opposite sleep pattern. There's evidence that we're genetically predisposed to be larks or night owls, he says, and the limited data collected so far suggest it's very difficult to change your times of optimal functioning.
You can get a night owl to get up early for work or exercise, in other words, but you can't necessarily get him to perform as well as he would at 1 a.m.
Whitbourne is more optimistic about your ability to change your sleep patterns.
"People injure their arm and have to learn to use the other hand," she says. "Our brains are very adaptive. We can train ourselves to do almost anything within reason."
For her, the key question is: How much sleep are you getting? It should be seven or eight hours a night, she says, whether you're a lark, an owl, or a lovebird who is attempting a new sleep schedule.
SIDEBAR: Changing your sleep patterns
Psychology professor Susan Krauss Whitbourne offers tips for lovebirds aiming to change wake-up times so they're more in sync with each other:
Gradually move your bedtime forward or back, making sure to get seven or eight hours of sleep.
Wind down before bedtime and put away your digital devices.
Make your bedroom a work-free zone.
Avoid caffeine late in the day.