For seven years, Gail Ennis has been spending up to three hours a day behind the wheel of her Subaru, commuting between her law office in Washington, D.C., and her home on Gibson Island, Md. What she's gotten out of the 100-mile daily round trip is sciatica — a shooting pain down one leg — and a lack of time for exercise.

"It's just too much and getting worse every year," Ennis said.

Besides taking time away from family, a long commute can be harmful to your health.

Researchers have found that hours spent behind the wheel raise blood pressure and cause workers to get sick and stay home more often. Commuters have lower thresholds for frustration at work, suffer more headaches and chest pains, and more often display negative moods at home in the evenings.

Carpool passengers also deal with what they call "Mustang neck" or "Beetle neck" — the contortions they make to wedge themselves into the back seats of certain cars.

In cities where grueling commutes are a way of life, drives can be as much as an hour each way on a good day — and there aren't many good days. As a consequence, more drivers will probably suffer the health effects of a commuter lifestyle, researchers and doctors said.

"You tell someone they need to exercise or go to physical therapy, but how can they? They leave at 5 a.m. and get home at 7 or 8 at night," said Robert Squillante, an orthopedic surgeon in Fredericksburg, Va., who has treated patients for back pain and other commuting-related problems.

Constant road vibrations and sitting in the same position for a long time is bad for the neck and spine, he said, and puts special pressure on the bottom disc in the lower back, the one most likely to deteriorate over the years.

Raymond Novaco, a professor at the University of California-Irvine Institute of Transportation Studies who has researched commuting for three decades, found a correlation between traffic congestion and negative health effects such as higher blood pressure and stress.

Novaco's research team measures the blood pressure and heart rate of commuters shortly after they arrive at work and again two hours later.

Commuters also fill out detailed questionnaires on their home and work lives. "The longer the commute, the more illness" and more illness-related work absences occur, he said.

"If you're driving an hour-and-a-half each way twice a day for 30 years, the consequences don't catch up with you at 32, they catch up in your 50s," said Jerry Deffenbacher, a professor of psychology at Colorado State University, who uses a computerized driving simulator to test the connection between traffic congestion and anger. "Like smoking, it wouldn't be immediately obvious."

Novaco's research showed that long solo commutes are especially tough on women, who generally "had more responsibility for getting family up and running and were significantly more likely to report being rushed to get to work," he said.

Squillante said some of his surgery patients have said the best thing about a back operation was the forced hiatus from their daily commute during recovery.

Patients are desperate for solutions and swear by certain types of car-seat pillows or jury-rigged lumbar supports, Squillante said, though he knows of no sure-fire solution.

Robert Cervero, chairman of the Department of City and Urban Planning at the University of California-Berkeley, has studied the relationship between the design of communities and physical activity. Rising rates of obesity and some types of diabetes contribute to the problems facing commuters, he said. But so, too, do the lifestyle choices — and land-use decisions — that result in long commutes.

Caryn Hutson, who works for a Washington property firm, leaves her "dream home" in Haymarket, Va., some 40 miles away, at 5:30 a.m. and gets home at 6:30 p.m. — if traffic cooperates.

"It's just tiring," Hutson said. By midweek, "I'm running on fumes. That's the biggest toll. It's not enough sleep."