How Sleep Changes as We Get Older (and Why)

by Martin Reed Patient Advocate

A 2017 study published in the journal Sleep argued that little is known about how sleep changes over the course of our lives. This prompted researchers to investigate how sleep changes among adults over 20 years and to try and determine what factors influence these changes.

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Study participants

Researchers collected data on participants in five separate rounds between 1987 and 2012. The study included adults who had participated in at least four rounds of data collection. This led to a total study population of 3,695 adults.

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How sleep data was collected and categorized

In each round, participants were asked how many hours of sleep they got over a 24-hour period. Those who slept for six hour or less were defined as short sleepers, those who slept for between seven and eight hours were defined as moderate sleepers, and those who slept for nine hours or longer were defined as long sleepers. Sleep quality was measured based on the Pittsburgh Sleep Quality Index.

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Health and lifestyle data

Researchers also collected data on age, marital status, education level, work status, smoking status, alcohol consumption, and caffeine consumption. Participants also reported their physical activity levels and health histories.

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Measuring sleep duration over 20 years

The study found that just over half (56 percent) of participants enjoyed persistent moderate sleep duration over 20 years. Three percent lived with persistent short sleep duration, while only one percent lived with persistent long sleep duration.

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How sleep duration changed over 20 years

Forty percent of participants experienced a change in their sleep duration over the 20-year period. Seventeen percent became short sleepers, 10 percent became moderate sleepers, nine percent became varying sleepers, and four percent became long sleepers.

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Risk factors for shorter sleep

The study revealed that those who began to get less sleep as time went on were more likely to be unemployed or blue collar workers. Those who were persistent short sleepers were more likely to be male, 30 years or over, and unmarried.

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Persistent short sleep duration linked to poor sleep quality

Perhaps unsurprisingly, those who did not have a persistent moderate sleep duration over 20 years were more likely to complain about sleep quality. At the end of the 20-year period, 58.4 percent of persistent short sleepers reported frequent nighttime awakenings and 44.3 percent reported finding it difficult to fall asleep after awakening.

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The decline in sleep duration

This study found that sleep duration changed for nearly half of all participants and more than one in six participants became short sleepers over the course of 20 years. Its authors suggested that today’s 24/7 "switched-on" society may be partly to blame. However, previous studies that have set out to investigate this theory have reported mixed results. So, what’s going on?

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Changes in sleep may be entirely natural

As pointed out by the authors of the study, sleep duration naturally becomes shorter as we get older and this is part of the natural aging process. Our circadian rhythm tends to get weaker as we age and additional health issues (and medications) can also affect sleep. Since this study followed participants over 20 years, it likely captured these natural age-related changes in sleep.

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The importance of good health and exercise

Perhaps the most interesting finding of this study was its identification of poor self-rated health and leisure-time physical inactivity as being consistently linked to almost every change in sleep. This emphasizes the importance of good health and exercise on long-term sleep duration and sleep quality.

Martin Reed
Meet Our Writer
Martin Reed

Martin is the creator of Insomnia Coach, an eight-week course that combines online sleep education with individual sleep coaching. His course helps clients improve their sleep so they can enjoy a better life with more energy and start each day feeling happy, healthy, rested, and refreshed. Martin also runs a free sleep training course that has helped over 5,000 insomniacs. He holds a master’s degree in health and wellness education and studied clinical sleep health at the University of Delaware.