Middle-aged women are the most stressed-out people in the country

It's no surprise that people are stressed out these days. We're juggling our jobs, financial problems, and parenthood, our families and relationships and heath issues. But of all of the people in the United States, new research shows, one group stands out as the most stressed: women between the ages of 45 and 64.

According to data released today by the Gallup-Healthways Well-Being Index, women in that age range have the lowest well-being of any age group, regardless of gender. And experts suggest that the problem actually starts much earlier.

Women age 35 and up are more aware of their own mortality and less able to physically rebound from stress the way they used to, explains Thea Singer, author of "Stress Less: The New Science That Shows Women How to Rejuvenate the Body and the Mind". "We also have that 'sandwich' role, parenting our young children and caring for our aging parents."

Throw in our careers and a struggling economy, and those stress levels skyrocket.

Chalk some of it up to supermom syndrome and that elusive work-life balance. "We thought we could do everything, and do it really well," says Singer. "Then you get older, and you get to mid-life, and think, 'Maybe I'm not really doing any of that really well.' And that's another stressor." All of that stress takes a toll, not just mentally, but physically as well.

"Women that are excessively stressed have very high cortisol levels," Dr. Holly Thacker, director of specialized women's health at the Cleveland Clinic, told ABC News. "Many of them scrimp on sleep to put [first] all the dominions of work and home and care giving and everything else that they're doing for everyone else. So with not enough sleep, not enough time for exercise and good nutrition and high cortisol stress levels, you know it's a recipe for a metabolic disaster."

Not all stress is bad for you, though. "Acute stress-short term, intermittent stress, or 'challenge' stress-is actually good for us," Singer points out. That includes physical activity like exercise and even sex. The problem is when stress becomes constant, and you don't have a chance to recover.

Suggestions for stress-busting abound, but the bottom line is that women have to make a conscious effort to take better care of themselves.

"Like the old adage," Thacker says. "When you're flying on a plane, put your oxygen mask on first before you assist others."

Also on Shine: