THURSDAY, Oct. 29 (HealthDay News) -- Feeling stressed at work? If you're younger than 50, it might get worse -- at least for a while.

Researchers from the University of Nottingham in England report that stress levels peak when people reach their early 50s but start to dip as they move toward old age.

That's not necessarily good news, either: Work-related stress apparently stays with people into retirement.

The findings come from a new report that analyzed hundreds of research publications from the last two decades.

"Work-related stress is thought to be responsible for more lost working days than any other cause, and it is becoming clear that it is also one factor affecting older workers' willingness and ability to remain in the labor force," the report's lead author, Amanda Griffiths, a professor of occupational health psychology, said in a university news release. "Therefore, protecting tomorrow's older workers, as well as today's, will pay dividends as older workers will form a major part of tomorrow's workforce."

The researchers said their study attempted to fill a gap in research that had focused on workers as a whole and not tended to look at age groups in particular.

They found that people who are older than 50 to 55 could have less stress for several reasons: They might have retired already, gained seniority that offers more control over their work or opted for a less-stressful position.

"As we get older, people's priorities may also change," Griffiths said. "They often have caring responsibilities or wish to spend time with grandchildren and develop other interests. Their work and career may not be their primary drivers."

"Making work attractive and flexible, to allow older people to balance work and their other interests more easily, may be one very important step forward," she said.

More information

The American Institute of Stress has more about stress and health  .

THURSDAY, Oct. 29 (HealthDay News) -- Want to improve that osteoarthritis in your knee? New research suggests that regular Tai Chi exercise can reduce pain and help your knee function better.

"Tai Chi is a mind-body approach that appears to be an applicable treatment for older adults with knee osteoarthritis," Dr. Chenchen Wang, co-author of a study published in the November issue of Arthritis Care & Research, said in a news release from the journal's publisher.

In the United States, an estimated 4.3 million adults over 60 suffer from this form of arthritis. As many as half of American adults may develop symptoms by age 85, the U.S. Centers for Disease Control and Prevention reported recently.

Wang and colleagues from Tufts University School of Medicine recruited 40 patients, with an average age of 65, who had been diagnosed with knee osteoarthritis.

Half of the group took part in Yang-style Tai Chi sessions for an hour at a time, twice weekly over a period of three months. The Tai Chi session consisted of 10-minutes of self-message and review, a half hour of movement, 10 minutes of breathing exercises and 10 minutes of relaxing.

The other participants took two 60-minute classes per week for three months and learned about issues such as diet and nutrition, and treatments for osteoarthritis. They also stretched for 20 minutes.

Those who practiced Tai Chi had significantly less knee pain than the other group and also reported less depression, more physical function and better overall health.

"Our observations emphasize a need to further evaluate the biologic mechanisms and approaches of Tai Chi to extend its benefits to a broader population," Wang said.

More information

Learn more about osteoarthritis from the Arthritis Foundation  .

MONDAY, Oct. 12 (HealthDay News) -- The ability to perceive relationships between objects (visuospatial skills) may decline years before a person is diagnosed with Alzheimer's disease, a new study suggests.

It included 444 people who were dementia-free when they were enrolled in the study and underwent tests on a number of cognitive abilities, including visuospatial skills. The assessments were repeated at least once before the end of the study. After an average follow-up of 5.9 years, 134 participants had developed dementia. Of those, 44 underwent brain autopsies that confirmed they had Alzheimer's disease.

The researchers used data from the cognitive assessments to chart declines in various areas before participants were diagnosed with dementia. They found an inflection point (sudden change to a steeper slope of decline) in visuospatial abilities three years before clinical diagnosis of dementia.

Declines in overall cognition occurred the next year, while inflection points for verbal and working memory weren't seen until one year before diagnosis.

The findings appear in the October issue of the Archives of Neurology.

"There are several implications of this study," wrote David K. Johnson, of the University of Kansas, and colleagues. "Some of the earliest signs of preclinical disease may occur on tests of visuospatial and speeded psychomotor skills. Furthermore, the greatest rate of preclinical decline may occur on executive and attention tasks. These findings suggest that research into early detection of cognitive disorders using only episodic memory tasks, such as word lists or paragraph recall, may not be sensitive to either all of the earliest manifestations of disease or the most rapidly changing domain."

"In summary, converging longitudinal evidence suggests that after a sharp departure from the relatively flat course of normal aging, there is a preclinical period in Alzheimer's disease with insufficient cognitive decline to warrant clinical diagnosis using conventional criteria but that can be seen with longitudinal data from multiple domains of cognition and not just memory."

More information

The U.S. National Institute on Aging has more about Alzheimer's disease.