Dramatic swings in temperature this week help us to realize why weather can make us sicker and crazier.
Biometeorology -- the study of weather's impact on living organisms including humans -- uses different terminology but concludes that weather itself, but specifically dramatic shifts in weather, can impact physical and even mental health.
The good health news? Experiencing such horrible stretches of weather better prepares us for what National Weather Service meteorologist Lee Hendricks said is a strong likelihood of another cold snap this winter. The so-called polar vortex, blamed for the sub-zero temperatures, could send us into another mental and physical vortex before spring.
"It's a huge swing physiologically," Jennifer Vanos, a biometeorologist and assistant professor of atmospheric science at Texas Tech University, said about Tuesday's record low of minus 9 degrees Fahrenheit sandwiched by unseasonable highs in the 50s. "People were not prepared. Physiologically, adapting is a tough thing to do when you are used to certain weather day after day."
But if another cold snap occurs, "people will be prepared," she said, especially for those 20 and under who never experienced such sub-zero temperatures. "They will know what to do, how to dress, and it won't be as stressful."
Long airplane rides usually are necessary for such swings in temperature. It's like flying round trip from Myrtle Beach, S.C., to the Yukon.
The Associated Press reported 21 deaths nationwide from the cold snap, most in the Midwest.
The normal high locally for early January is 36 degrees with a low of 21. In the week ending Saturday, if the forecasted high of 52 holds true, the region will have experienced a 61-degree swing. Last Monday alone saw a temperature swing of 57 degrees -- 50 to minus 7, Mr. Hendricks said.
Along with potential dangers of extremely low temperatures, including hypothermia, frostbite and blood vessel constriction leading to heart attacks, quick shifts in barometric pressure, high or low, represents an unsuspected health villain.
Ms. Vanos said people are most comfortable with barometric pressure of 30 inches of mercury (inHg). When it rises to 30.3 inHg or higher, or drops to 29.7 or lower, the risk of heart attack increases. High barometric pressure constricts blood vessels, which hinders blood flow, while low pressure expands blood vessels, making it more difficult for the heart to pump blood. The highest prevalence of heart attacks occurs within 24 hours of swings of that magnitude in barometric pressure, she said.
"That effect is strongest in the fall and winter," she said.
It's not yet known whether the rate of heart attacks increased this week.
Jack Boston, senior meteorologist at AccuWeather.com, said barometric pressure rose from 29.77 inHg at 7 a.m. Monday to 30.36 inHg by 7 a.m. Tuesday.
Ms. Vanos, among others, says changes in barometric pressure also cause headaches, migraines, arthritis, joint pain, and sinus and inner-ear problems.
But in an unexpected seasonal twist, Mississippi State University meteorologist Grady Dixon said suicide rates drop during the winter. The peak season for suicides is June, he said, but the reason remains a mystery.
"Usually the thing people are most interested in or surprised to hear is that while people have depression in the cold, dark winter months, suicides around the globe, with no exception, most commonly occur during the late spring and early summer," he said. "It's the broken-promises effect. If you are clinically depressed and have seasonal affective disorder, you expect spring to be better. But if you are clinical ill, you probably won't get better in the spring when you expect to feel better. It's not a weather effect but the lack of a weather effect that causes the suicide."
January does bring the year's highest mortality rate, likely due to higher rates of infections, including influenza deaths and other weather impacts on people, especially the elderly.
The National Weather Service said temperatures will climb to the lower 40s today, then to the low 50s on Saturday before dropping back to the low 40s on Sunday. The weekend will feature drizzle, rain, freezing rain and snow, which won't accumulate, with total precipitation of a half to three-quarters of an inch.
Mr. Hendricks said this winter's weather extremes are occurring because we're in a transition between el nino and la nina weather patterns, which are nearly yearlong weather trends involving the heating and cooling of the north and northeastern Pacific Ocean.
Despite the temperature extremes, with more likely to come, winter highs and lows will average near normal by winter's end. We've also had more than double the normal snowfall for the season, with 30.3 inches through Wednesday, as compared to the normal of 13.5, he said.
Temperatures are expected to return to normal by Wednesday.
Weather and climate psychologist Alan E. Stewart of the University of Georgia said men and women react differently to severe weather.
Women are more cautious than men. Maximizing reproduction requires caution, with a slight tendency for expectant mothers to spend their final trimester during late spring and summer months before giving birth in August or September. Winter weather historically has posed harsh challenges for moms and babies to stay warm, find food and avoid infections.
CDC statistics showed that 9 percent of all babies in 2010 were born in August with 7.5 percent born in February. OK, the numbers aren't dramatic, but the trend holds.
Men are a different story.
"Men take more weather-related risks than women, including driving across roadways that have water flowing, or being outside during thermal extremes, or not taking cover when thunder is heard and lightning is seen, or not sheltering when there's word from the National Weather Service of a storm or tornado," said Mr. Stewart.
David Templeton: firstname.lastname@example.org or 412-263-1578.