Early to bed helps girls handle stress.

• Position: Your Life - Brief Article

Being in bed by 9 p.m. makes youngsters better able to respond to stress than those who stay up later, according to a Brown University, Providence, R.I., study of 138 third-grade girls, ages eight and nine, residing in New York City. Researchers measured their levels of the stress hormone cortisol, blood pressure, and perceptions in relation to three stressful tasks during a home visit.

"Kids typically encounter all sorts of stressors in their lives," indicates Vincent F. Capaldi, the study's lead researcher. "If you are able to cope with stress, you are better able to learn and less prone to illness."

The pupils completed a block design task that challenged their intellect, applied a cold compress to their foreheads that mimicked physical stress, and had a conversation with their mothers on a topic about which they disagreed. The girls chose the topic from a list of issues such as manners, telephone calls, actions with siblings, behavior toward the mother, going to church, and taking care of tapes and compact discs.

Levels of cortisol were measured at the beginning of the interview and after each stressful task. Those with earlier bedtimes registered a greater initial spike and steeper decline in cortisol when faced with stress, compared to girls with later bedtimes. That strong response suggests girls with earlier bedtimes have a better-regulated...