The day my life changed, I sat on crinkly paper in a blue hospital gown. A surgeon had cut wide incisions to remove skin cancer—melanoma—in four places on my back and neck. I had 34 stitches taken out, and the scars were the length of a hand, but there was good news. I was healing. As far as the surgeon knew, the cancer hadn’t spread, and I thought the hard part was over.

　　Then, the surgeon delivered a blow.

　　A blood test showed I had a genetic mutation. The CDKN2A gene in all of us regulates cell division. Mine is faulty, which makes the risk of cancer returning high. While genetics will probably have the greatest influence on my health, managing environmental risks is important. Limiting sun exposure is my best shot at survival. The ideal amount of UV exposure for someone like me? None.

　　The walk home was long. I had trouble digesting what the surgeon had said. I have spent much of my life in the sun, but not for the tan. I am a climber, a runner, a paddler, and a skier. Moving through mountains, over lakes, and across snow is who I am.

　　I met my husband, Dave, while working for Outward Bound in Oregon. We fell in love in the desert, climbing, drinking cheap beer, and sleeping in the back of his Datsun wagon in Joshua Tree. We’ve since moved to the city, Toronto, and had two boys who are now teenagers, but we drag those boys outside every chance we get, in canoes, hiking boots, and on skis. Getting outside is more than what we love. It’s us.

　　Dave has a cheery disposition, but his smile dropped when he saw me walk in our front door. He put his arms around me, kissed my hair, and asked what happened at my appointment. I explained that while the surgeon had acknowledged it was impossible to avoid UV exposure altogether, he said I needed to aim in that direction. I saw my disbelief reflected in Dave’s face.

　　“I’m from California?” he said, as if there were a way to plead our case. I started thinking about all the time we’d spent outside together. I was 45 years old, with boys who still needed me, and our relationship might never be the same. Neither would I.

　　My dad died from melanoma, the most deadly kind of skin cancer, when he was 42 years old. His started as a spot on his arm when he was in his thirties. Back then, doctors didn’t know the genetic cause of the disease, the human genome had yet to be mapped. They did, however, understand the risks of the sun. My dad started wearing long sleeves, wide brims, and sunscreen to protect his skin.

　　Skin cancer is the most common kind of cancer in the United States. The American Academy of Dermatology estimates that one in five Americans will have it in their lifetime. Everyone is exposed to Ultraviolet (UV) radiation, a form of energy from the sun. And we need to be; our bodies use it to produce vitamin D. However, too much exposure to UV can damage the DNA in your cells, creating a misfire. The abnormal cells divide and spread.

　　Limiting sun exposure is my best shot at survival. The ideal amount of UV exposure for someone like me? None.

　　About a decade after the spot on my dad’s arm was removed, his cancer returned. It had found its way into his lymph nodes. My memories from that time are hazy, but I remember watching the effects of chemotherapy take hold. I went to his room to say good night and found a man who was bald, skeletal, frail—I wasn’t sure this was my dad.

　　He died when I was in fifth grade. Too young to cope, I shut down. I had trouble feeling anything for a long time.

　　I found sensation again on a month-long canoe trip in my early teens. Soon, I discovered climbing. I felt the highs and all the lows on a long trail, a slab of granite, or skiing on a glacier. As I gained experience, I took pride in my ability to respond to the elements, endure tough times, and keep going. In the wilderness, I came back to life.

　　A year after my operation, Dave and I took a trip into the backcountry in a canoe. We went to Algonquin Park, a wilderness area where I have led trips and traveled extensively, about three hours north of Toronto, Canada. The fall colors burst into a riot around us. The sky soared overhead. In my hands, the paddle felt like an old friend. The first J-stroke, a rounded pry that maintains the canoe’s forward momentum, felt incredibly elegant.

　　I wore a wide-brimmed hat, a long-sleeved shirt, and tons of sunscreen, but when Dave turned in the bow, he saw the reflection of the water dappling on my chin. It was late on an October afternoon, and the monitor on my phone showed a low UV index, but the water and the aluminum canoe were acting as reflectors.

　　Neither of us said anything, but we paddled to our campsite in silence. Given the risk, it wasn’t a smart place for me to be. In someone else, their natural immunity might stop cancer cells from duplicating. It’s much less likely in me. A year after our trip to Algonquin Park, I found melanoma in my eye. I had a gruesome operation to have it removed. Luckily it was superficial, but I’ve had more melanoma since. We were right to be worried about the exposure.

　　The trip became like a farewell, each graceful stroke an act of mourning.

　　We decided to try and swim at dusk. The UV was low, but the water was freezing. I chickened out, so Dave dove in for both of us. We wrapped in a blanket to watch the sunset from a rock. The giant orb in the sky slid down. It gave us light and warmth; it fueled the growth of our stunning surroundings, but it didn’t wield that power lightly.

　　The next morning, Dave pulled out the map of canoe routes. He pointed to a second set of lines on the map. Hiking trails ran in every direction through the park. I’d been too obsessed with my J-stroke to see them before. We started talking about how a different mode of travel might be safer. We could hike in the morning and evening, take a shady siesta, and choose routes covered by the canopy. In retrospect, I can’t believe I hadn’t thought of such a simple thing, but I had been looking in the wrong direction.

　　“What if this isn’t our last canoe trip,” Dave said, “but the first day we start backcountry hiking?” Before our eyes, the park opened up.

　　I could still take pride in how I responded to the elements, and my condition would be just another risk I had to manage. In the past, I had learned to be prepared—for a storm, for plunging temperatures, for an unexpected whipper while climbing. Now, Id have to prepare for UV exposure, too.

　　Now, the dark days of November are my favorite. If its raining, that means conditions are perfect, and I pull up my hood and head out. Dave and I hike in the mist, or at the crack of dawn, and often have the trails to ourselves. When the moon is full, on a clear night, I’ve had some of the best cross-country ski outings of my life. I love the coldest days in winter because they require every inch of skin to be covered. I swim with the boys at dusk—the colors of a sunset look like magic from the water. On a truly gloomy day, preferably when it’s drizzling, I’ll go out in a canoe. The elegance of a J-stroke still brings me to tears. I will never take it for granted.

　　Cancer has changed the range of what I can do. Now, the risks are much greater, but being near the edge has always sharpened my senses and trained my mind. I’m aware of the wonder in every moment I spend outside. I’ve never been so alive.