Obesity may lead to heat-related problems, officials say

It's a good thing Houston is one of the country's slimmest cities, eh? Otherwise, the streets might be littered with the immobile bodies of obese people struck down by the heat — you see, obese people are at high risk for heat-related illnesses, health officials say. Time to hit the treadmill!

Though heat warnings have long focused on children, the elderly and the socially isolated — people who don't get outside much? — non-fatal heat exhaustion can be a big problem for the overweight, whose layers of fat serve as insulators that keep body heat from escaping in hot weather (though that's not such a bad thing in the winter). What's more, because the body cools itself by circulating blood to dissipate heat through the skin, obese people's hearts must pump blood much harder on hot days. Overweight people are also prone to sweating more, which means they can become dehydrated more quickly than other people.

Though all those are things to keep in mind, scientists still aren't sure of the exact correlation between obesity and heat-related complications and death: George Luber, an epidemiologist with the CDC, said no one's sure yet at what level of obesity a person becomes at high risk from heat. Luber did note that a recent CDC report looking at 1,200 heat-related deaths between 1999 and 2003 found cardiovascular disease was a major factor in 57 percent of the deaths and diabetes was a major factor in 3 percent — both conditions that tend to affect the obese. "Obesity kind of represents several risk factors rolled into one," Luber said.