Your Brain on Nature

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It controls depression, improves athletic performance, helps battle cold, flu and cancer and has been shown to speed recovery time after sickness. A new medical marvel?

Nope. Just the great Canadian outdoors.

Ironically enough, as scientists increasingly find links between our well being and spending time in nature, fewer and fewer of us are actually doing it.

Last year, the David Suzuki Foundation found that 70 percent of 13 to 20-year-olds are outside less than an hour each day. Meantime, says the renowned Kaiser Foundation, those same kids are spending a whopping seven and a half hours a day on entertainment media.

“The overall message is that we’ve turned our backs on the potential benefits of nature,” observes Alan Logan, co-author with Harvard Medical School’s Dr Eva Selhub of Your Brain on Nature: The Science of Nature’s Influence on Your Health, Happiness and Vitality (Wiley). “Research going back decades have shown that even something as simple as a walk in the forest has health benefits. That really is the bottom line.”

Get outdoors.

Want to sharpen your mind, boost your immune function or de-stress? Find a forest.

According to Japanese research by Chiba University and the Nippon Medical School, the relatively recent practice of shinrin-yoku (‘forest air bathing’), or a walk through trees, does more than pass the time. Scans have shown that after just 20 minutes, blood flow in the brain actually changes to a state of relaxation.

And it can improve immune function, too. Blood tests by Nippon Medical School researcher Qing Li revealed that a day trip to the forest actually increased the number of natural killer (NK) cells the body produces to battle infection and made them more active for up to a week later.

Perhaps less surprising is how nature can improve mood. In work by Dr Marc Berman at Toronto’s Baycrest Rotman Institute, depressed adults showed marked improvements not only in mood, but memory function as well.

So how does it work? Researchers are still debating that, but Berman says it’s partly to do with how our attention operates. Whether we’re focused on natural surroundings or not, our involuntary attention—the one that gently registers bird song, wind in leaves or the smell of fresh earth—actually revitalizes a fatigued mind. Plus, you don’t even have to enjoy it to have the benefits.

In his research, patients took walks in June and in January. They didn’t enjoy the mid-winter stroll as much—no surprises there—but they still experienced improved memory and mood.

Part of the answer might also come from the trees themselves. While they can’t talk, they do communicate with us through chemical secretions called phytoncide, which scientists have known about since the 1800s. Recently, experimental studies have shown that phytoncide can lower the production of stress hormones, reduce anxiety and increase pain threshold, while inhaling aromatic plant chemicals increases the antioxidant defense system in the human body, Logan says. And they can be cancer-protective: Nippon Medical School studies found a correlation between the amount of forest around you was compared to cancer mortality rates. In other words, the more forest, the lower the rates of lung, breast, uterine, prostate, kidney and colon cancers.

Screen save those nature photos.

Far from the forest, scenes of natural beauty also have a profound impact. According to Logan, brain scans comparing how we react to urban versus natural images are markedly different. “When you view the image of nature, the area of the brain associated with emotional stability and love would become more active. In contrast, the urban images activated the flight or fight centres.”

Even viewing the outdoors from inside can be beneficial. In the 1980s, pioneering researcher Dr Robert Ulrich examined a decade of medical records of patients who had gallbladder surgery at a Pennsylvania hospital. Some patients were wheeled into recovery rooms with a park view; others had a window facing a wall. “The outside view was significantly associated with fewer days in hospital,” says Logan, “fewer complications and lower amounts of negative comments on charts by nurses.”

Get a plant.

Not only do indoor plants filter air and beautify your environment, they’re good for your mood, too. Just having a plant within view reduces anger, anxiety, depressive thoughts and fatigue by 40 percent and stress by 50 percent over three months, says a 2010 study by the University of Technology, Sydney. Just don’t overdo it: University of Illinois scientists testing how indoor plants affect productivity got some surprising results when they put participants into rooms with no vegetation, 10 potted plants or 22 plants. Amazingly, those in the lushly vegetated room felt the best, but they performed even worse than those with no plants.