Melissa Lem

Canada’s Green prescription initiative: a history-making quest in a natural paradise

Melissa Lem’s first job as a practising physician was in northern British Columbia. There she was, a newly minted rural family doctor in her twenties, providing full-service primary care, delivering babies in the middle of the night, and managing critically ill patients in a rural emergency room surrounded by forest, bears and mountains. 

As an adult, nature remained that safe place where she felt she belonged and would go to de-stress, a connection that had grown steadily since childhood. And it was after beginning work as a family physician that it “snowballed.” 

Dr. Melissa Lem, MD, CCFP, FCFP, is Director of PaRx, Canada’s national nature prescription program, powered by the BC Parks Foundation. She will give a presentation during the III Ibero-American Summit Nature, Health and Well-being.

Nature was where I felt safe, where I went to find solace when I was stressed as a child. I grew up in a majority white neighborhood in Toronto and didn’t always feel like I belonged: I was bullied on the school ground, and on the sidewalk, because there really weren’t many people who looked like me. 

“I found that it was in my father’s traditional Chinese vegetable garden, in the park down the street, in the ravine, or in the trees and the bushes on the edges of the school ground where I felt like I belonged.

“My favorite National Park is probably Pacific Rim National Park Reserve, on Vancouver Island. When I was in residency, training to be a family physician, I remember walking onto the beach for the first time and seeing the end of it disappear into the mist. Just a feeling of expanse. And the bullwhip kelp, this massive, long seaweedit was a magical experience. You can’t help but feel awe when you’re in an environment like that. 

“I was a rural family physician in Northern BC, where I was suddenly surrounded by more nature than I’d ever really experienced in my life. I was a new graduate running the emergency room, delivering babies in the middle of the night. I loved it, because whenever I would have a stressful shift or a long day at work, immediately I would go into the hospital garden or walk across the road to hike up a beautiful mountain. I could see mountains out my front window and bears walking across my driveway.” 

Green Prescription

“Back in Toronto I realized, listening to the streetcars and looking at all the glass and concrete, the reason I felt stressed was because I was missing nature. And I thought, this intuitive sense I have can’t be real unless it’s backed up by randomized control trials and research. So I sat down at my computer and hundreds of studies popped up.

“I thought, I didn’t learn about this in medical school. I haven’t heard other doctors talking about the health benefits of nature. I need to make it my mission to communicate this to the public, to my colleagues, so everyone knows that they can de-stress, and get healthier when they spend time in nature. And it just snowballed from there. In 2018 I began collaborating with the BC Parks Foundation—the official charitable partner to BC Parks—and with the support of their dedicated and creative staff, and the credibility and authority of a major nature-focused organization, we were able to launch PaRx, Canada’s national nature prescription program, together. 

How “much” nature to prescribe?

“In our program we have a standard recommendation that you spend at least 2 hours in nature each week, at least 20 minutes each time. And these targets are based on studies that came out in 2019. One of them showed that people who spent more than 120 minutes in nature each week reported significantly better health and well-being.

“The 20 minutes recommendation comes from another study in 2019 that showed that between the 20 and 30 minute mark is when your drop in cortisol, or stress hormone, is the fastest.

“What’s great is that you can reap those health benefits whenever you feel like you’ve had a meaningful experience in nature. You don’t have to be on a deserted beach, or in the middle of the forest, or on the side of a mountain.

“You can find nature in your garden, in a neighborhood park, walking with friends along a trail or by the beach. It’s very self defined”.

Open minds: the fourth pillar of health

“We need to open our minds and be willing to accept a new mode of practice. Even though nature prescriptions were named one of the top eight global wellness trends in 2019, obviously it’s not mainstream across the world yet, but it is evidence based. It does improve patients’ health. And we should be seeing it as the fourth pillar of health, just as important as a healthy diet, exercise, and sleep in maintaining a healthy lifestyle. 

“At the III Ibero-American Summit I’ll be speaking about the evidence behind the health benefits of nature, the theories behind why nature is so good for our brains and bodies, and also describing our nature prescription program and some of the successes it’s had around the world and in Canada.

“Prescribing nature is an effective planetary health intervention: you protect what you love. And people who are more connected to nature are also more likely to engage in other pro-environmental behaviors, like recycling, like energy conservation, and advocating for climate action. So it also builds a body of people who are more connected to nature, aware of how important the planet is for our health and will also be motivated to protect it.

“We have over 7,000 registered prescribers in Canada, which I think is amazing just a year and a half after our first launch. If you’re a Canadian licensed healthcare professional, you can register to prescribe at”. 

Nature prescription, a “shocking” progress in health

“The patient I remember best is a woman who had moved from Europe, and was suffering with anxiety and depression.. During our first appointment,I asked her how much time she was spending outside, and she said, I’m afraid to spend time outdoors because the parks are more crowded than I’d like. Though I do remember I felt much better when I used to hike back home.” This was during COVID lockdown.

“I initially prescribed her medication, as she had asked. And then, following up during our second appointment after PaRx had launched, I asked ‘How would you feel if I wrote you a prescription for nature? At least 2 hours a week, at least 20 minutes each time, and maybe spending time with friends outside because it’s much safer than being inside. And she said, 'Okay, I’ll try that’. And I gave her her nature prescription.

“I still remember the words she said to me a month later: ‘I’m shocked at the progress I’ve made. I’m less anxious. I’m going outside and connecting with friends, and I feel so much better. Thank you. I think this is just what I needed.’

“I think in this case, it was probably a combination of medication, plus the permission to go outside, the permission to prioritize nature as an essential part of her lifestyle, that made the difference.”


Ph: Courtesy Melissa Lem

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