Preschoolers have boundless energy and need plenty of exercise to burn it off. According to the National Association for Sport and Physical Education, preschoolers need at least two hours of exercise every day [source: The Children's Hospital]. If your preschooler is active, she'll sleep better, feel stronger, and be less susceptible to childhood obesity and diabetes.
Keep in mind that children often mimic their parents in terms of fitness. Fit parents tend to have fit children. Monitor your own physical activity levels to ensure that you're setting a good example.
There are two types of exercise for preschoolers: structured and unstructured. Structured play is planned activity, such as playground games (tag, hopscotch, etc.) or group sports. Structured play allows your child to develop her physical coordination while learning the basics of cooperation and teamwork. Unstructured, or free, play is when your child is left to do activities on her own, such as drawing, exploring, or playing with toys. By giving your child space, she is able to develop creativity, imagination and emotional strength. Give your child an even balance of both structured and unstructured play.
In all play, safety is essential. Preschoolers haven't completely developed their balance or coordination, and they haven't fully formed the basics of common sense. Put a helmet on them when they ride their tricycle, supervise them in parks and playgrounds, and be especially watchful when they swim in a pool.