Children spend about 40% of their childhood asleep. Those restorative hours of slumber are as important to a child’s health as nutrition and exercise, allowing the body and brain to flush out toxins, consolidate memories, release growth hormone, lower stress hormones like cortisol, as well as repair and replenish cells. Poor sleep can lead to excess weight gain, diabetes, learning and memory problems, daytime tiredness, moodiness, clumsiness and accidents, and trouble paying attention. Unfortunately, studies suggest that over the last century, the amount of sleep that children get has been declining.