Sleep time and genetics interact to affect active life

Lifestyle and economic factors play an important role in shaping healthy ageing, but their effects can vary depending on your DNA, according to a new international study led by researchers at Adelaide University.

The study is the first of its kind to show that diet, exercise, sleep, smoking, education, work and social interactions all influence how we age, with varying effects depending on a person’s genes.

Researchers have focused on a key indicator of healthy aging, “inner potential”, which represents the sum total of all physical and mental energy used throughout life. This enables people to maintain healthy functioning and perform daily activities, such as personal care, household and living activities, and communication and recreational activities.

Using data collected from more than 13,000 participants in the Canadian Longitudinal Study on Aging (CLSA), they found that good health older age (higher internal strength) was associated with more physical activity, better diet, higher education, employment and social relationships.

On the other hand, low internal energy – or activity that has decreased with age – was associated with smoking and insufficient sleep time, including shorter and longer than recommended sleep.

“Intrinsic fitness, a hallmark of healthy ageing, is influenced by a complex interaction between genetics and environmental and lifestyle variables,” said lead author Associate Professor Azmeraw Amare, a researcher at Adelaide University’s School of Medicine.

Our findings suggest that genetic factors can influence the way lifestyle and lifestyle factors influence the dynamics, highlighting the interplay between genes and the environment that lead to healthy aging. “

Azmeraw Amare, Associate Professor, University of Adelaide

Both short and long sleep durations were found to be detrimental to healthy aging. The negative effect of short sleep was reduced among people with genetic advantages (carrying high genes for internal energy). On the other hand, the negative effect of sleeping for a long time for middle-aged people (45-64 years) was more visible, even though they had high genes for internal energy.

Following a Mediterranean-style diet and getting a higher education were very beneficial for long-term health, with consistent benefits even among people with a low genetic predisposition to internal stress.

“Genetic effects were more pronounced in middle age than in later life, suggesting that accumulated lifestyle and social exposure may play an increasingly important role in determining functional capacity as people age,” said first author Melkamu Bedimo Beyene, a PhD candidate at Adelaide University’s School of Medicine.

This is the first study to determine how interactions between genetics and lifestyle variables, such as diet quality, education level and sleep duration, are linked to inner strength.

“The good news is that some of these factors are changing. Our research findings can help create more ways to prevent and promote health for healthy aging,” said University of Adelaide Professor Renuka Visvanathan, who is an expert in Geriatric Medicine.

“By focusing on maintaining the ability to work rather than waiting for death to occur, we can better support autonomy and quality of life throughout adulthood and later life.”

The findings were published in The Textbooks in Gerontology: Biological Sciences.

The team now plans to evaluate clinical and community health strategies that focus on life-changing conditions, and hopes that this will promote long-term health and early intervention to prevent functional decline.

“Discovering how healthy aging processes are created during both biological life and lifelong exposure is important for developing policies that support functional capacity in older adults,” said Professor John Beard, Irene Diamond Professor of Productive Aging at Columbia University.