Jeri Solomon is a morning person but Jim, her husband of 11 years, is not. Early in their life, it caused a problem. "When we were planning our wedding, I wanted to have these big discussions at 8 a. m.,when I had been up for two hours and was fresh, but Jim would just be getting out of bed," says the 46-year-old designer from Melrose, Mass. "We ended up getting into many arguments because I thought he had no interest, when really he was just still half-asleep." The couple learned to work around their differences over the years, but their situation isn't uncommon, says Katherine Sharkey, professor at BrownUniversity. "More women tend to be larks, while men are like night owls ," she says. The question is:Why? The answer lies in each person's body clock. "The body clock is about 24 hours, thanks to Earth's 24-hour light-dark cycle," Sharkey says. "But some people have a longer natural cycle, and some are shorter." If yours is on the long side, you're more likely to be a night owl. If it runs short, you're probably an early riser. But your body clock can change over your lifetime. There's a developmental piece-school-age children are generally early birds, while teenagers tend to be night owls, and then as they age, adults gradually turn back into morning people," Sharkey says. Besides the clear problems with being a night owl if you have fl day job, "night owls tend to be more low-spirited, and have a higher dependence on coffee," Sharkey says. But the news isn't all bad. A recent study in Belgium found that night owls can stay more focused as the day goes on, compared with early risers. Morning people, however, also have advantages. "Larks generally sleep better, have more regular sleep, and have more flexible characters," Sharkey says. They also tend to be happier and feel healthier than night owls, according to a recent study from the University of Toronto. Jeri Solomon and her husband   _  .
tried to change each other's sleeping habits often argued about small things could not understand each other got up at different times