In announcing her "Let's Move" initiative, First Lady Michelle Obama said that when she was young, "we spent hours running around outside when school got out. You didn't go inside until dinner was ready." That's the childhood many of us remember, but the seven hours and 38 minutes kids today spend in front of electronic media leaves little time for outdoor play. No wonder our children's health is being jeopardized. Let's move outdoors and encourage our kids to Be Out There ( Lack of outdoor time has been linked not only to increased obesity, but depression, stress, diabetes, ADD and poor performance in the classroom. It's time parents took advantage of an old-fashioned, low-cost remedy to our children's obesity problem. Let's fling open the back door and let kids do what comes naturally, running around in green spaces and making friends with nature. Leave those unwanted pounds behind a tree, in a stick fort, under a slimy rock or on top of that big boulder that looks like Sponge Bob Square Pants. KEVIN COYLE, RESTON, VA.;