How does South Florida's warm climate affect your health?

Here's a cold, hard fact: No matter how long you live in South Florida, your blood will not thin out and make you sensitive to chilly weather.

On the one hand, if you move from a cold to a warm climate, you might lose some fat because your body will no longer need as much insulation. You also will be less prone to get the winter blahs because of all the sunshine in these parts — yet that sunshine also can increase your chance of contracting skin cancer.

You'll be more likely to develop sinus problems because of all the air conditioning in South Florida homes and buildings. And, if you're one of those who leaves the windows open, you might not sleep as well in the subtropical heat.

Thinner blood, however, "is absolutely a myth," said Dr. Bruce Lenes, medical director of Community Blood Centers of South Florida, noting that blood thickness isn't influenced by temperature. He said people simply adjust — mentally and physically — to a new climate.

"It's just a matter of getting used to the warm," he said.

Martin Zenor, of Boca Raton, said when he moved to South Florida 16 years ago, he used to wear T-shirts and shorts in the winter, even when it was cool outside.

"Now I bundle up with layers if it gets colder than 60," said Zenor, who grew up in Iowa. "I complain about the cold to family and co-workers, particularly this winter and last winter."

It's forecast to get cold again Saturday night and Sunday morning, with temperatures falling into the mid- to upper 40s. But it should be short-lived, with near-normal readings Monday and Tuesday.

While warmer temperatures don't thin out blood, living at high altitude does, Lenes said. That allows people who live in the mountains to function with less oxygen in their blood.

Otherwise, the only other physiological change of moving to a warm climate is that people tend to lose fat, a process that takes a couple of years, said Dr. Charles Rouault, president of Community Blood Centers of South Florida.

Conversely, he said, mammals that live in arctic regions develop a layer of fat to insulate against the cold. The fat is created when cold prompts estrogen to bind with fat cells, which then multiply.

"That's why whales and walruses are fat," he said.

Blood aside, people usually sleep better in cooler temperatures. The reason: The body's temperature decreases in sleep, and a cool room aids that process, experts say.