Study links stable sleep patterns to successful aging

A study reveals that stable, moderate sleep patterns are linked to better health in older adults, while inconsistent or short sleep trajectories pose risks to physical, cognitive, and social well-being.

Study: The association between sleep duration trajectories and successful aging: a population-based cohort study. Image Credit: Shutterstock AI

A recent study published in the BMC Public Health journal explored how different sleep duration patterns relate to ‘successful aging’ among older adults in China. The study emphasized that both sleep duration and consistency are important factors for healthy aging outcomes. Their findings indicate that increased and short sleep patterns are linked to a lower probability of successful aging, emphasizing the critical nature of monitoring sleep changes among older and middle-aged adults.

Background

The population of people over 60 worldwide is expected to rise from 12% in 2015 to 22% in 2050. China, in particular, has a rapidly increasing aging population, projected to reach 397 million and account for 28% of the population by 2040. Its life expectancy (77.6 years on average) is far greater than its healthy life expectancy, which is only 68.4 years.

High sleep variability impacts aging: Not only do shorter and longer sleep durations affect aging outcomes, but greater fluctuations in sleep duration over time are also linked to lower odds of successful aging.

Successful aging is defined as living longer while maintaining cognitive and physical health, social engagement, and mental well-being while remaining free of major diseases. Less than 16% of older adults in China achieve this compared to significantly higher rates in South Korea and Japan. Promoting successful aging in the Chinese population requires identifying modifiable risk factors.

Both excessive and insufficient sleep have been linked to adverse outcomes like depression, cognitive decline, and mortality. However, prior studies have shown mixed results related to the links between successful aging and sleep duration, with one study in China finding associations between short sleep and lower odds of successful aging and another in the United States suggesting that long sleep may reduce the likelihood of aging healthily.

Previous studies have not accounted for long-term changes in sleep duration over time, focusing instead on sleep duration measured at a single point. Persistent short sleep is associated with higher risks of mortality, dementia, heart disease, and type 2 diabetes, but the relationship between sleep patterns over time and successful aging has not been explored.

About the Study

Mental and physical health effects: Consistently short sleep patterns may elevate cortisol levels and inflammation, which can accelerate age-related health issues such as cognitive decline and muscle loss.

In this study, researchers investigated how different sleep duration patterns related to successful aging among older and middle-aged Chinese adults and how monitoring these patterns could inform public health strategies.

The study used data collected using longitudinal surveys administered between 2011 and 2020, designed to be representative of adults over 45 across China. The final analysis included 3,306 participants who were disease-free at baseline and over 60 in 2020.

The total sleep duration of participants was calculated by combining sleep at night and naps during the day using self-reported data on sleep habits. Sleep patterns reported in 2011, 2013, and 2015 were analyzed to ascertain the trajectory of sleep habits.

Researchers defined successful aging based on five criteria, including the absence of chronic diseases like heart disease, cancer, and diabetes; independent physical functioning for daily activities; cognitive functioning; minimal depression symptoms; and social well-being through engagement in social activities like community events or games.

The analysis used a latent class mixed model to classify participants’ sleep duration trajectories into distinct patterns and employed logistic regression models to estimate the odds of successful aging for different sleep trajectory groups. The analysis was adjusted for factors such as body mass index (BMI) and lifestyle factors, including physical activity, drinking and smoking, income, education, residence, marital status, sex, and age.

Findings

The median age of the 3,306 participants was 60, and nearly half were female. Over nine years, 81% had no major chronic diseases, but only 13.8% met the criteria for successful aging.

Researchers identified five sleep patterns: short stable, increasing, decreasing, long stable, and normal stable. The group with normal stable sleep patterns showed the highest successful aging rates, at 18.1%. Normal stable and long stable sleep patterns were more favorable for successful aging, while short stable, increasing, and decreasing sleep patterns were associated with lower odds of successful aging. Notably, the decreasing sleep trajectory was not statistically significant, likely due to the sample size.

Sleeping less than seven hours was also found to reduce the odds of successful aging, and participants with high variability of sleep duration also had lower chances of successful aging. These findings were consistent across different groups, including weight classes, smoking and alcohol intake, sex, and age.

Conclusions

Researchers showed that a consistent, normal, stable sleep pattern is the most favorable trajectory for successful aging. Chronic short sleep may elevate stress hormones (like cortisol) and increase inflammation, which can raise the risk of age-related diseases. Long-term sleep issues may be tied to mental and cognitive declines, sarcopenia (muscle loss), and disrupted metabolism. Gradual increases in sleep duration could indicate health issues like sleep apnea or depression, which also affect successful aging.

Importantly, these findings support the concept that consistency in sleep is as critical as duration for positive aging outcomes. They suggest that persistent sleep deficits or progressively increasing sleep duration are barriers to successful aging, highlighting the importance of dynamic sleep monitoring as a preventive measure.