Mismatched sleep patterns can be more than an inconvenience - they can actually affect the quality of your marriage, says a researcher at Brigham Young University.

Jeffry H. Larson, an associate clinical professor at BYU, said couples whose sleep patterns are mismatched - where one is a "night person" and the other prefers mornings - have less satisfaction in marriage than couples who have the same sleep-wake patterns."The matched people had higher marital satisfaction, higher marital adjustment, they spent more time talking and doing things together and they argued less frequently," Larson said.

Mismatched couples in the study had more arguments, spent less time in serious conversation or shared activities and had less frequent sexual intercourse.

"They're constantly missing each other," Larson said. "Their energy levels are different, their comings and goings are different and when they feel like interacting is different."

Past studies on "circadian," or 24-hour rhythms, have shown that most people can classify themselves as morning or night people.

Morning people prefer physical and outdoor activities and find their energy peaks early in the day. Night people experience energy peaks in mid-afternoon or late evening and prefer quiet activities at home.

The BYU study, conducted by Larson, BYU faculty member Russ Crane, and Craig Smith, a member of the University of Nebraska faculty, was based upon a sampling of 150 couples from Utah, Montana and Alabama.

Larson said he is convinced that sleep-wake patterns can be significant factors in a relationship and at times can cause clashes between partners. But he said they're not as significant as other factors that might affect the marriage. "It's a less important consideration than other background or personality factors, like communication skills, background, religion, values or the ability to solve problems."

Larson, who works as a counselor in BYU's Counseling and Development Center and teaches in the department of family sciences, said many couples live with the situation through compromising, taking turns on each other's schedules.

"In some cases, the morning person can take an afternoon nap. Some couples take turns staying up late or going to bed early. With good communication skills and a willingness to compromise, most couples can learn to adjust to their different rhythms."