Women's study finds longevity means getting just enough sleep

ScienceDaily (Oct. 1, 2010) — A new study, derived from novel sleep research conducted by University of California, San Diego researchers 14 years earlier, suggests that the secret to a long life may come with just enough sleep. Less than five hours a night is probably not enough; eight hours is probably too much.

A team of scientists, headed by Daniel F. Kripke, MD, professor emeritus of psychiatry at UC San Diego School of Medicine, revisited original research conducted between 1995 and 1999. In that earlier study, part of the Women's Health Initiative, Kripke and colleagues had monitored 459 women living in San Diego (ranging in age from 50 to 81) to determine if sleep duration could be associated with mortality.

Fourteen years later, they returned to see who was still alive and well.

Of the original participants, 444 were located and evaluated. Eighty-six women had died. Previous studies, based upon questionnaires of people's sleep habits, had posited that sleeping 6.5 to 7.5 hours per night was associated with best survival. Kripke and colleagues, whose 1990s research had used wrist activity monitors to record sleep durations, essentially confirmed those findings, but with a twist.

"The surprise was that when sleep was measured objectively, the best survival was observed among women who slept 5 to 6.5 hours," Kripke said. "Women who slept less than five hours a night or more than 6.5 hours were less likely to be alive at the 14-year follow-up."

The findings are published online in the journal Sleep Medicine.

Kripke said the study should allay some people's fears that they're not getting enough sleep. "This means that women who sleep as little as five to six-and-a-half hours have nothing to worry about since that amount of sleep is evidently consistent with excellent survival. That is actually about the average measured sleep duration for San Diego women."

Researchers uncovered other interesting findings as well. For example, among older women, obstructive sleep apnea (pauses in breathing during sleep) did not predict increased mortality risk. "Although apneas may be associated with increased mortality risk among those under 60, it does not seem to carry a risk in the older age group, particularly for women," Kripke said.

Co-authors of the study include Robert D. Langer of the Jackson Hole Center for Preventive Medicine; Jeffrey A. Elliot and Katharine M. Rex of the UCSD Department of Psychiatry; and Melville R. Klauber of the UCSD Department of Family and Preventive Medicine.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California -- San Diego, via EurekAlert!, a service of AAAS.

Note: If no author is given, the source is cited instead.

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Study confirms: Whatever doesn't kill us can make us stronger

ScienceDaily (Oct. 15, 2010) — We've all heard the adage that whatever doesn't kill us makes us stronger, but until now the preponderance of scientific evidence has offered little support for it.

However, a new national multi-year longitudinal study of the effects of adverse life events on mental health has found that adverse experiences do, in fact, appear to foster subsequent adaptability and resilience, with resulting advantages for mental health and well being.

The study, "Whatever Does Not Kill Us: Cumulative Lifetime Adversity, Vulnerability and Resilience," to be published in the forthcoming issue of the Journal of Personality and Social Psychology, is available on the website of the American Psychological Association.

It examined a national sample of people who reported their lifetime history of adverse experiences and several measures of current mental health and well being.

Authors are Mark Seery, PhD, assistant professor of psychology at the University at Buffalo; E. Alison Holman, PhD, assistant professor of nursing sciences, University of California, Irvine; and Roxane Cohen Silver, PhD, professor of psychology and social behavior and medicine at UC Irvine.

Seery, senior author of the study, says previous research indicates that exposure to adverse life events typically predicts negative effects on mental health and well-being, such that more adversity predicts worse outcomes.

But in this study of a national survey panel of 2,398 subjects assessed repeatedly from 2001 to 2004, Seery and co-researchers found those exposed to some adverse events reported better mental health and well-being outcomes than people with a high history of adversity or those with no history of adversity.

"We tested for quadratic relationships between lifetime adversity and a variety of longitudinal measures of mental health and well-being, including global distress, functional impairment, post-traumatic stress symptoms and life satisfaction," Seery says.

"Consistent with prior research on the impact of adversity, linear effects emerged in our results, such that more lifetime adversity was associated with higher global distress, functional impairment and PTS symptoms, as well as lower life satisfaction.

"However," says Seery, "our results also yielded quadratic, U-shaped patterns, demonstrating a critical qualification to the seemingly simple relationship between lifetime adversity and outcomes.

"Our findings revealed," he says, "that a history of some lifetime adversity -- relative to both no adversity or high adversity -- predicted lower global distress, lower functional impairment, lower PTS symptoms and higher life satisfaction."

The team also found that, across these same longitudinal outcome measures, people with a history of some lifetime adversity appeared less negatively affected by recent adverse events than other individuals.

Although these data cannot establish causation, Seery says the evidence is consistent with the proposition that in moderation, experiencing lifetime adversity can contribute to the development of resilience.

"Although we studied major lifetime adversity," he says, "there is reason to believe that other relatively mundane experiences should also contribute to resilience.

"This suggests that carefully designed psychotherapeutic interventions may be able to do so, as well, although there is much work that still needs to be done to fully understand resilience and where it comes from."

Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University at Buffalo, via EurekAlert!, a service of AAAS.

Journal Reference:

Mark D. Seery, E. Alison Holman, Roxane Cohen Silver. Whatever does not kill us: Cumulative lifetime adversity, vulnerability, and resilience.. Journal of Personality and Social Psychology, 2010; DOI: 10.1037/a0021344

Note: If no author is given, the source is cited instead.

View the original article here