Frank Poole worked out at a gym and hiked around his Mississippi home carrying a weighted pack for months in preparation for his trip to the Grand Canyon.
But it wasn't long after Poole started hiking on a popular Grand Canyon trail that he was struggling to breathe. Several hours later, he was in a northern Arizona hospital, where doctors determined the 75-year-old Poole had suffered a heart attack.
"I never suspected I was having a heart attack," Poole said recently from his home in Oxford, Miss. "I just thought it was the heat and extra exertion, the altitude and things like that. I was just so naive."
At the Flagstaff Medical Center — northern Arizona's only Level I trauma center, and the place where Poole was treated — officials have a name for the spring and summer months when many tourists travel to the canyon. They call it "Grand Canyon Season."
Emergency workers at the park and hospital officials know they'll start seeing more people with injuries or those who, like Poole, didn't know they had underlying health conditions that surfaced during the strenuous hikes at the canyon.
The canyon lures millions of people each year with its colorful landscape, immense size, and awe-inspiring geology. But it presents obstacles that can leave even experienced hikers emerging sore and fatigued, including scorching heat during summer months, an altitude of 7,000 feet, and steep, rocky, winding trails.
"There's a million ways you can hurt yourself down there," said Lon Ayers, who works in the park's backcountry office.
The last few weeks have illustrated that.
In late April, an Ohio man fell 60 feet when he was peering over the edge of the canyon and lost his balance. Two days later, two teenagers and a young man who were swimming in the Colorado River at the bottom of the canyon were swept away and drowned. Another injury occurred when a mule lost its footing on a trail, fell and rolled over the passenger it was carrying.
Falls, fatigue, extreme temperatures and horseplay at national parks around the country lead to nearly 3,600 search and rescue operations each year, according to 2007 figures. The park service also responds to 16,000 emergency medical calls a year for anything from abrasions to twisted ankles, heat stroke and cardiac arrest, said Dean Ross, NPS branch chief of emergency services in Washington, D.C.
Rangers at the Grand Canyon perform more rescues than at any other park, including 300 helicopter rescues a year, said Ross.
People who come prepared, bringing plenty of snacks and water, and who pace themselves and listen to their bodies fare the best.
"Don't be afraid to try it, (but) take it easy," said Dave Florence of Green Bay, Wis., who recently completed a 40-mile, five-day hike at the canyon.
But hikers don't always heed warnings from rangers and on signs posted around the canyon.
Allan Widener of Louisville, Ky., recently took the Bright Angel trail just off the canyon's South Rim. After a park staff member strongly recommended that Widener not head down without water, the hiker quipped that, "I don't drink water, I drink Coke."
On the way back from his 1½ mile hike, leaning against the canyon wall in a shady spot, the 48-year-old said he wished he'd had something to drink.
Park rangers say they generally encounter three types of people hiking in the canyon. There are the strong-headed ones, usually in their teens and 20s who have an invincibility complex and will go against recommendations. Others are excited and unprepared but willing to change plans if needed.
Then there are people like Albert Shank, who are prepared and generally stick to plans they've made, but sometimes get in trouble because of circumstance or because they made a bad decision, said Marc Yeston, deputy chief ranger.
Shank was about 28 miles into what was supposed to be a 42-mile rim-to-rim run in April when his legs started cramping and his body refused to keep down any food or water. He nearly collapsed on a park bench and spent several hours having saline pumped into his body before he was able to walk out of the canyon.
The Arizona State University faculty associate, who often runs distances longer than marathons, had plenty of water, energy bars and peanut butter and jelly sandwiches but not enough electrolytes or salty food.
"That was a rookie mistake, and I'm not a rookie," he said. "I learned that no matter how good of shape you're in, the canyon is something you need to respect, and dehydration will take you down."
What can be deceiving at the Grand Canyon is that the temperature at the South Rim, where 90 percent of all visitors go, is about 20 degrees cooler than at the bottom. And while most trails lead hikers up a mountain before the downward descent, it's the opposite at the Grand Canyon.
"It's a unique set of circumstances," Ayers said. "People from all over the world need to at least hear it from somebody on what to expect. People who have never hiked the Grand Canyon before expect it to be a walk in the park."
Some hikers do undertake extraordinary preparations. But other times, rangers say they aren't sure what people were thinking. They've seen a man in a business suit carrying a briefcase full of water bottles, a man playing a tuba and people hiking without shoes or in flip-flops.
"It all stems from a lack of preplanning and knowledge of these trails," said Ian Buchanan, a seasonal park worker who advises people on smart hiking. "A lot of people get the sense that it's Disneyland when it's an environmental park."
This time of year, 30 percent of the heart patients at Flagstaff Medical Center are brought in from the canyon with conditions such as valve and rhythm problems, and heart disease and blockages.
Since the hospital started its open heart surgery program in 2004, there has been at least one month where all heart attack patients came from the Grand Canyon, said Gigi Sorenson, the hospital's cardiopulmonary services director.
"You just get used to it," she said. "And now when tourist season kicks in, you just start to expect when they call and say they're coming from the canyon."
Poole, who had three clogged arteries, was the hospital's first open heart surgery patient after his heart attack at the canyon in 2004. He said his general good health, the exercise he did in preparing for his trip and willingness to seek help spared him from a more serious problem.
He hasn't had any complications with his heart since the surgery. "My heart's in good shape now," he said.