Sometimes the best medicine for children is a big dose of playing outdoors.

Remember mom’s medicine for boredom and bad behavior? “Go outside and play!” An exciting field of research, called the neuroscience of nature, validates that Dr. Mom was right. Enjoying the health effects of a walk in the woods or playing in the park is especially therapeutic in this modern age.

Nowadays, many children sit indoors in front of a screen for entertainment, and they are feeling the effects — weakened immune system, mood problems and childhood obesity. Modern-day kids have a green-grass deficiency. What medicine do they need? The great outdoors! The sights and sounds of nature both relax the mind and invigorate the body. The colors, the movement and the fresh air are just what the doctor ordered.

A tale of two kids

Gracie grows up green. Since her bed faces the window she wakes up to the sights and sounds of nature. Her bedroom is flowered with plants and kid-playing scenes on the wallpaper. And smart Dr. Mom enforces the “go outside and play” prescription when Gracie needs a little perk up. Tom the Techie, on the other hand, is glued to a screen most of the day and doesn’t enjoy mom’s medicine of “go outside and play.” Unlike Gracie, Tom is more likely to eventually fall victim to the ailments of a new illness coming into the doctor’s dictionary, the sitting disease. Movement in the great outdoors, or what Japanese neuroscientists term “forest bathing,” is one of the best medicines for growing brains and bodies.

In my medical office I practice what I call the pills-skills model of health care. Parents are asking for less prescription pills and more self-help skills for their children. This mindset prompts your doctor to shift from a medical mindset into more of a self-help mode, from what the doctor prescribes to what the doctor advises. One of my top medicines that I prescribe: Move more.

How nature heals

On your way to your nature walk suppose you went by your neighborhood neurologist and got wired with cameras (called functional MRIs) that peer inside your brain to reveal what’s going on in there as you are walking outside. Here’s a list of some of the fascinating health effects neuroscientists have discovered from a simple walk in nature: decreased heart rate, more relaxed blood pressure, increased happy hormones, decreased stress hormones, mellower moods, stronger immune system, and fewer fearful thoughts.

Neuroscientists dub the beauties of nature “visual valium.” The insightful statement “it’s pleasing to the eyes” also applies to the brain since the eye is simply an extension of the brain. A reminder I often say during my nature walk is: “Eye feel good.”

Imagine inside your body and brain you have command centers full of dials, which are adjusted and set just right for your physical and mental well-being. These dials are interconnected by chemical lines — hormones— that enable each system to communicate with the others. When you walk outside the eye- brain says to the heart: “Relax, you don’t need to beat so hard and fast.” Then it says to the intestinal dials, “Gut, feel good!” Movement helps every organ of the body work more efficiently.

Why movement is the best medicine

Brisk movement causes blood to flow faster over the surface of the endothelium, a layer of cells lining the interior surface of blood vessels, and your body’s largest endocrine organ. If you were to open all your blood vessels and spread them out flat, your endothelium would cover the surface area of several tennis courts. Each cell of the endothelium is its own endocrine organ, filled with “microscopic medicine bottles” that release health-promoting substances into the bloodstream at just the right time, in the right amount, with no harmful side effects — and they’re free. The fast- moving blood creates an energy field called shear force, which releases a natural biochemical called nitric oxide. Nitric oxide acts as a biochemical key to open your pharmacy and dispense the medicines you need. The more you exercise, the more your endothelium gets used to the extra blood flow.

Science agrees. In a revealing study, boys labeled ADD were divided into two groups: One got an extra 20 minutes a day of “prescribed” vigorous exercise; the other group didn’t. Compared with the “sitters,” the “movers” showed remarkable improvement in their ADD, especially in their ability to sit still and focus.

Here’s my wish for a healthy school program. Let’s call it: “no child left (on their) behind!”

Bill Sears, M.D., is a father of eight and the author of 42 books on family health, including The Healthiest Kid in the Neighborhood.A practicing pediatrician for over 40 years, he is an Associate Clinical Professor of Pediatrics at the University of California, Irvine, School of Medicine. Dr. Sears is a fellow of the American Academy of Pediatrics (AAP) and a fellow of the Royal College of Pediatricians (RCP).