BALTIMORE — Poor sleep in midlife might have consequences for psychological well-being years later, especially in women, a new study suggested.

In a longitudinal analysis of participants in the MIDUS study, sleep problems reported in midlife were associated with poorer psychological well-being nearly a decade later. The association remained significant among women but not among men after adjusting for demographic, health, and baseline psychological factors.

“Sleep problems are sometimes viewed as a normal part of aging, but our findings suggest they may have important long-term implications for psychological well-being,” lead author Fumiko Hamada, MA, a doctoral student and sleep researcher in the School of Aging Studies at the University of South Florida in Tampa, Florida, told Medscape Medical News.

“Sleep problems experienced repeatedly over days, weeks, and years could gradually influence psychological well-being if they are not addressed,” Hamada noted.

The study was released on June 2, ahead of presentation on June 17 at the SLEEP 2026.

Sleep’s Long Reach

Age-related changes in sleep are well documented, and previous research has shown an association between poor sleep and depressive symptoms.

“However, we wanted to broaden the focus beyond depression and examine psychological well-being,” Hamada said.

She also noted that women’s health has historically been underrepresented in research, prompting an investigation into whether biological sex influences the relationship between sleep and long-term well-being.

The researchers examined data from 574 adults who participated in MIDUS surveys conducted in 2005-2006 (baseline) and again in 2013-2017 (follow-up). Participants had a mean baseline age of 51 years, and 55% were women.

Sleep quality was measured using the Pittsburgh Sleep Quality Index, while psychological well-being was assessed using a validated questionnaire encompassing domains such as autonomy, environmental mastery, personal growth, purpose in life, positive relationships, and self-acceptance.

In the unadjusted model, more sleep problems reported at baseline were associated with lower psychological well-being at follow-up in both men and women (P < .001), although the association was stronger in women.

In adjusted models, poorer sleep remained significantly associated with worse psychological well-being among women, whereas the relationship was no longer statistically significant among men.

Although the study was not designed to identify mechanisms underlying the sex differences, “the most likely explanation is that sex differences in both biological and social factors shape the relationship between sleep problems and psychological well-being,” Hamada said, noting that more research is needed.

Underappreciated Contributor to Well-Being

A key aspect of the study is the long view on the impact of sleep, said Amy Mechley, MD, a lifestyle and family medicine physician based in Cincinnati, who was not part of the research.

“In clinical practice, we often think about poor sleep as causing next-day fatigue, irritability, or reduced focus,” Mechley told Medscape Medical News. “This study reinforces that sleep health may also be tied to emotional resilience and psychological well-being years later.”

Women in midlife often face overlapping biological, psychological, and social stressors that can make sleep disruption more consequential, she noted.

“When sleep is chronically impaired, the body has fewer opportunities to regulate stress physiology, inflammation, appetite, glucose metabolism, and emotional processing. Over time, that can erode psychological well-being,” Mechley said.

Sleep remains an underappreciated contributor to emotional well-being, affecting diet, physical activity, social connection, and overall mental and physical health, she said.

"When sleep is impaired, every other health behavior becomes more difficult to sustain,” said Mechley, adding that many people do not allow enough time for sleep.

“There remains a widespread misconception that most adults can function optimally on 5-6 hours of sleep per night. The evidence consistently shows otherwise,” she said. “Most adults require 7-9 hours of sleep on a regular basis, and while people may adapt to feeling tired, they generally do not adapt to the cognitive, emotional, metabolic, and physiologic consequences of chronic sleep restriction.”

The study received no commercial funding. Disclosure information for study authors is available in the original study publication. Mechley disclosed serving as chair on the board of directors for the American and International Boards of Lifestyle Medicine.