Part of every day at Lextended day is going outdoors, except in more extreme weather conditions. We find the children are happier when we do and most have a real drive to be outside. This is also a great opportunity for unstructured, imaginative play, gross motor skills, and opportunity for social and emotional development.
Most research I see is in support of increased outdoor time. This article shares a number of theories.
More on potential effects on asthma an ADHD here