BAKERSFIELD, Calif. -- According to a study published in Archives of Disease in Childhood, around one in six parents says that he or she has a child who finds it difficult to get to sleep.

Researchers studied the daytime activity and sleep patterns of hundreds of 7-year-olds by giving them activity monitors to wear for 24 hours.

They found that children with the highest levels of activity during the day fell asleep the most quickly at night.

But every hour spent in sedentary activity increased the time it took the children to fall asleep by an average of three minutes. In addition, children who took longer to fall asleep slept for shorter amounts of time.

The study points to the importance of activity not only for physical fitness but also for healthy sleep, which is critical for many aspects of well-being, including overall brain health.