Study Finds Biological Link Between Stress, Rapid Aging

The "first direct link between stress and aging" has been identified by researchers from the University of California-San Francisco and colleagues, helping explain why people who undergo long-term emotional strain are more prone to physical illnesses and accelerated aging, the Washington Post reports. For the study, published online Tuesday in the Proceedings of the National Academy of Sciences, researchers studied 39 women ages 20 to 50 who were experiencing prolonged stress while caring for a child with a serious chronic illness, such as autism or cerebral palsy. Those women were compared with 19 similar women whose children were healthy. The researchers examined structures within cells called telomeres, which are located at the ends of chromosomes. They analyzed white blood cells taken from participants' blood samples (Stein, Washington Post, 11/30).

Telomeres become shorter each time a cell divides, so they "effectively mark a cell's biological age," according to the San Jose Mercury News (Landhuis, San Jose Mercury News, 11/30). As part of the natural aging process, the telomeres eventually become so short that cells can no longer divide, and they die, which results in the outward physical manifestations of aging.

The researchers found that the longer a participant had been caring for a sick child -- and thus had been under stress -- the shorter her telomeres. In addition, the mothers who had been under the most stress had lower levels of an enzyme called telomerase, which helps rebuild telomeres and staves off the aging process; telomerase levels naturally decline with age. Mothers under the most stress also had higher levels of oxidative stress, which is a process in which free radicals in the body damage DNA, including telomeres.

In addition, the researchers found that people's perception of their level of stress was a key factor. Women with the highest levels of perceived stress had telomeres equivalent to someone 10 years older when compared with women who had the lowest levels of perceived stress. The researchers speculate that chronically elevated levels of stress hormones, such as cortisol, damage the telomeres and other genes in the body and reduce telomere levels (Washington Post, 11/30).

"Chronic stress appears to have the potential to shorten the life of cells, at least immune cells," lead researcher Elissa Epel of UCSF said, adding, "This is the first time that psychological stress has been linked to a cellular indicator of aging in healthy people" (Los Angeles Times, 11/30). She said, "The findings emphasize the importance of managing life stress, to take it seriously if one feels stressed, to give your body a break and make life changes that promote well-being" (Perlman, San Francisco Chronicle, 11/30). Future studies will focus on whether stress-relief techniques, such as meditation and yoga, can slow the rate of telomere aging, the Mercury News reports (San Jose Mercury News, 11/30).

In a commentary accompanying the study, Robert Sapolsky of Stanford University, said, "This is a real landmark observation. This is a huge interdisciplinary leap ... a great study." Dennis Novack of Drexel University College of Medicine added that the study "demonstrated that there is no such thing as a separation of mind and body -- the very molecules in our bodies are responsive to our psychological environment" (Washington Post, 11/30).

NBC's "Nightly News" on Tuesday reported on the study. The segment includes comments from Epel (Bazell, "Nightly News," NBC, 11/30). The complete segment is available online in Windows Media.

In addition, NPR's "Day to Day" on Tuesday included an interview with Rob Stein from the Washington Post about the study (Chadwick, "Day to Day," NPR, 11/30). The complete segment is available online in RealPlayer.