ParkRx aims to provide 'prescription for wellness' by getting more people outside

ABC News is taking a look at solutions for issues related to climate change and the environment with the series, “The Power of Us: People, The Climate, and Our Future.”

A community health initiative that partnered with the National Park Service has doctors writing a "prescription" for wellness by getting more people outdoors.

"When I look across our medical system and the ability of doctors to use all the tools that they can — our parks prescription program is probably a key to that," National Park Service Director Chuck Sams told ABC News. "Getting [people] outside into the national parks, or any park for that matter, so that they can enjoy and get through recovery, so that they can reduce their stress level, so that they can center and focus on their own personal well-being — you can't ask for a better program."

ParkRx is part of the NPS "Healthy Parks, Healthy People" effort to encourage wellness through visits to the country's 429 national parks and other green spaces.

Founded in 2013 by the Institute at the Golden Gate and the National Recreation and Parks Association (along with NPS), the ParkRx "park prescription" program has since swept across the nation.

"ParkRx is a great movement by wonderful physicians around the country trying to motivate — also to get their patients into nature," cardiologist and ParkRx advocate Dr. David Sabgir told ABC News. "The benefits are amazing. It lowers our cortisol, which lowers our blood pressure, lowers our heart rate, makes our hearts healthy and mentally just being [outside] is incredible."

Research has shown that spending time outdoors can benefit your mental and physical health in a number of ways.

Exposure to sunlight can help build vitamin D, improving immune health and muscle function, according to the Harvard T. H. Chan School of Public Health. The American Psychological Association also notes time spent outdoors can create improvements in mood, cognitive function and overall well-being, among other impacts.

Sabgir is the founder of Walk with a Doc, one of dozens of ParkRx programs across the country. The program encourages patients to get outside and walk.

He sat down with ABC News medical correspondent Dr. Darien Sutton to discuss the program in Rock Creek Park, a National Park in Washington, D.C.

"I love Walk with a Doc," Sabgir said. "Physical activity is so important for our health. And, I was failing at motivating my patients to get out, so one day, I just said, 'how about if you join my family and I at the park?' And next thing we know, it's just been a ride of a lifetime."

Sabgir said walking 150 minutes a week, or 20-25 minutes per day can provide patients with the physical and mental benefits walking has to offer.

"And if you miss a day, it's okay," he added. "The key is just sticking with it."

"And I always think about this — walking versus running," Sutton said. "Do I have to be extra — exert myself beyond or can I just simply walk?"

"Walking really gets it done," Sabgir said. "Running gets it done a little faster, but you get all the benefits from walking and it's lower impact."

Walk with a Doc board member Chaun Hightower told ABC News that, for her, "walking is medicine."

"For me, it's a form of medicine. I use walking to sort of help me decompress from work — and taking care of a family keeps you super busy," Hightower added. "And when I get outside and I start walking, it just feels freeing — like the weight of the world starts to fall off of me when I have a chance to walk."

Sams echoed the benefits of spending time in the National Parks, calling them "America's crown jewel."

"England has its crown jewels. We have the national park system," he said. "Sometimes there's the question between nature and nurture, but you get both when you actually go into a national park. You become inspired. You become relaxed. It has so many benefits of learning our history, our culture, and also just interacting with the flora and fauna."

April 22 is Earth Day, a global celebration of the environment, and a part of National Park Week in the U.S.

ABC News' Youri Benadjaoud contributed to this report.