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Article Excerpt
This is an extract from Sunshot: Peril and Wonder in the Gran Desierto, just-published in the Southwest Center Series by the University of Arizona Press.
DEVIL'S DRIVEWAY
A friend and I planned to walk El Camino del Diablo in August. That translates to "the Devil's Highway" and 130 miles of searing, grand desert between Sonoyta, Sonora, and Yuma, Arizona. Undocumented immigrants, primarily from Mexico and Central America, pass through this blazing desert on their journey north--and every summer some die here. A hundred and fifty years ago, other pioneers braved the same highway. They were not always successful, either. Our hike would study the effects of heat stress out there by subjecting our own bodies to it.
But I got anxious and conducted a preliminary experiment. A warm-up test, so to speak. This seemingly crazy investigation was done at home in Tucson. In a closed automobile. It will live in lore as "la Calzada del Diablo." The Devil's Own Driveway.
This was the preview, the economy version of the full hike. Forget the backpack and long trail. The laboratory was sitting right there in front of the house: a shiny car in the bright June sun. All I needed was to gather a squad of thermometers and some basic medical gizmos to measure vital signs.
The modern car is a greenhouse of glass. Solar energy enters but can't leave. While this principle serves nicely to warm one's buns in winter, it torches them in summer. I knew that temperatures and pressures inside a closed car on a hot day could braise bare skin, crack dashboards, and even explode windows.
Even so, I readied my experiment with a few goodies, and at 10:00 a.m. sharp I popped into the car parked in my driveway and closed its doors. The doors had stood open for over an hour, and although the outdoor and shaded temperature was only 92 degrees, the car's interior was 98 degrees. No sweat. I had a giant-sized iced cola, a good book, and a radio. I was set for the rest of the day. Baseline pulse was sixty-two, blood pressure 118/78, respiration nine, and oral temperature 97.2 degrees. All systems were within normal parameters of operation.
Within the first seventeen minutes, I began to sweat, especially where the sun hit my bare legs. The inside temperature had risen to 114 degrees, while outside it was still 92 degrees. By 10:25 I had polished off a dozen pages of the book. The mercury had risen to 118 degrees, and my own stats had started to flutter. Pulse was up by sixteen, temperature by 0.4 degrees, and respiration by three. Though I was sitting still, my body acted as if it were working 25 percent to 33 percent harder.
Heat shimmered off the car's brown hood. The metal clipboard and even the paper on it were hot to the touch. A meat thermometer on the dash read 130 degrees. My shirt was soaked and I dripped onto the pages. By 10:42 sweat poured from my forehead and arms. Two minutes later I started to fidget and could no longer concentrate on reading. My hair was soaked. "This is only morning," I thought. "What'll the afternoon be like?" I drank some soda but wasn't really thirsty.
At 10:47 I began to feel my pulse throughout my head and chest. It was up to 92. Breathing was now twenty, and my temperature had warmed to 99.2 degrees. Blood pressure read 124/84. And I was sitting, not exercising. One thermometer was off its scale at maybe 126 degrees, and the dash gauge read 145 degrees. At 11:01, a headache sprouted, and I found myself subconsciously draping a towel over my exposed legs. I hadn't noticed, but my socks and cutoff jeans were soaked, too. Reading was out of the question. I couldn't keep the sweat off my glasses, so I tossed the book into the backseat.
At 11:09 my scalp started to itch, and a minute later I stared down the temptation to open the door. By then I knew that the experiment wouldn't last into the afternoon. By 11:15 my nose began to run uncontrollably. Sweat coursed from...
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