Children who exercise less during the day take longer to fall asleep at night, according to new research.
Every hour of inactivity is worth an additional three minutes that a youngster stays awake for, experts from the Monash University in Melbourne, Australia, and the University of Auckland in New Zealand said.
The research analysed the sleeping and exercise habits of 519 children born in 1996 and 1997 and followed up when they were seven. It was published in the journal Archives of Disease in Childhood.
It took the children an average of 26 minutes to fall asleep. The majority of them had dropped off within 40 minutes but some took nearly three hours.
Activity monitors were attached to the children so the scientists knew how much exercise each child had taken in their day-to-day lives.
Those who participated in more vigorous sorts of exercises were able to fall asleep much faster than those with sedentary lifestyles.
The research also showed that the children who were quicker to fall asleep also slept for longer.
The researchers said: ‘This study emphasises the importance of physical activity for children, not only for fitness, cardiovascular health and weight control, but also for sleep.’