On average, nearly 700 people die each year from extreme heat. It's the most serious threat to your outdoor summer workout, but there are ways to reduce the danger—if you're careful.
Heat stroke hits when your body's thermoregulatory system gets overwhelmed and fails in extreme temperatures. When this happens, it doesn't matter if you're running or walking: you're taking on heat faster than your body can release it.
"When you exercise in heat, there's a little competition happening inside your body," says Doug Casa, chief operating officer of the University of Connecticut's Korey Stringer Institute, named for the Viking football player who died in a 2001 team practice from heat stroke. Your muscles, heart, and skin each desperately want to maximize blood flow, and in extreme heat, they're forced to vie against one another for a finite amount of fluid. Muscles want to maintain performance, while the heart simultaneously strives to maintain ideal stroke volume without overworking itself.
Problems arise when the skin asks for more than its usual share, as it does when you exercise in heat. Your body only has four self-cooling methods: conduction, convection, radiation, and evaporation. "In 50-degree weather, the skin doesn't need much blood flow, and the muscles and heart can be happy," Casa says.
But when air temperatures range above your skin temperature—about 93 degrees—you instead absorb heat by the first three processes, and you're left only with sweat evaporation. Often that does the trick, but it taxes the body's limited fluid supply, particularly if you're dehydrated (for every one percent body mass lost from dehydration, your temperature rises about a degree).
In humid areas like the Southeast, the saturated air negates the water-vapor pressure gradient needed to evaporate your sweat, which means you're out of cooling options.
"Something's going to have to give," warns Casa. "Either you're going to lower your intensity, or you're going to have to somehow keep the sweat rate high." But that has its limits. Your body can handle the critical threshold temperature of 105.5 for around 30 minutes before cell damage ensues and internal organs begin to fail.
You might notice the onset of headache, dizziness, nausea, or excessive fatigue, but often there's no warning. "I had a heat stroke when I was 16, running the race of my life, and I felt nothing until my face planted on the track," Casa says.
Like edema victims on Everest, the only cure is retreat: back off the intensity and cool down with shade or a cold drink. Better yet, keep heat stroke at bay by hydrating, shedding layers, and relegating outdoor workouts to the cooler mornings or evenings. It's important, too, to acclimatize yourself to exercising in the heat with a slow transition over seven to ten days.
Even then, you'll never run a half marathon in 90 degrees as well as you will in 60, Casa cautions. "People still need to realize that they have to back off, and you can't have the same assumptions of how you're going to perform."
This canyon—in Glen Canyon National Recreation Area near the Arizona/Utah Border—housed a pool of water that was sheltered from any wind. The surface created a perfect mirror for the canyon walls lit by the late afternoon sun, which was rapidly descending towards the horizon. The lighting was changing every minute; at this time of day, you can sit in a single spot and take an evolving set of images of the same subject. Not all spectacular shots are obvious.
TOOLS: Panasonic DMC G3, 1/80 second, f/5.6, ISO 800
Haris Suleman had a goal: to become the youngest person to fly around the world in a single-engine plane in 30 days. Suleman and his father, Babar, were undertaking the trip in an attempt to raise $1 million in charity for Seeds of Learning, an organization that builds schools in Pakistan.
Tragically, the 17-year-old's trip—and life—were cut short when he and his father crashed Tuesday after leaving Pago Pago, American Samoa. There is no indication as to what caused the crash, according to the Federal Aviation Administration.
NBC News confirmed Suleman's body has been recovered, and authorities are still searching for his father. The duo started their journey on June 19 and planned to fly the 26,000-mile trip in exactly 30 days, with stops in 25 cities around the globe. The Sulemans were on the final leg of the flight, with stops planned for Hawaii and California, before arriving home in Plainfield, Indiana.
Suleman's sister, Hiba, posted a message on Facebook in honor of her brother and father.
I'd like to thank everyone for their support of my father and brother throughout this trip, as well as for the support given to my mom, brother, and myself as we waited for their safe return. Haris has been found; he did not make it. My father has not yet been found. Please pray that my dad is found alive and well. Also, hug your siblings and parents—tell them you love them, a hundred times. A thousand times. It will never feel like it's been said quite often enough.
World Cup fervor has settled in the Brazilian state of Ceara, but an unconventional partnership between the state, the U.S. government, and American small businesses will produce the country's next spectacle: Acquario Ceara, the largest aquarium in South America and the third largest in the world. The project might be the first example of a U.S. federal agency funding construction outside North America to create American jobs.
The aquarium, set to open in the city of Fortaleza in 2015, is being paid for almost entirely by the Export-Import Bank of the United States. The agency is financing construction through a $105 million direct loan it says supports 700 American jobs.
How? The Latin American branch of an Ohio design firm is designing Acquario Ceara, a metals firm in Missouri is constructing the blobist "crustaceo-exoskeleton," and a custom aquarium maker from Colorado is overseeing construction.
The project might seem like a win-win for all involved, but not so, Capps writes.
For one, if you build it, the 12 million expected annual visitors won't necessarily come. Fortaleza attracted only 219,430 international tourists to Brazil in 2010. Can the allure of one aquarium make up the difference? The aquarium might provide the next blow to the Bilbao Effect—the idea that constucting architectural spectacles brings in tourists, which paves the way for decadent cities. "An aquarium isn't a cultural facility, exactly—although this one sure looks like one, both in terms of design and the project's ostensible aim," Capps says.
Despite job creation for Americans, not everyone is happy stateside. Republican senator Mike Lee of Utah says the aquarium "erodes Americans' confidence in our markets and our system" with "taxpayer-backed loan guarantees to help American exporters."
Like fish in a fishbowl, everyone's watching Acquario Ceara, but only time will tell if the new aquarium will make a splash.