Sleeping well is an essential part of our longevity. Sleep protects our mental and physical health across our lifespan. And a routine of plentiful, restful sleep helps to keep in check many of the forces that accelerate the biological aging process.
During sleep, the body undertakes significant cellular repair and rejuvenation, the brain eliminates harmful waste and toxins. Our nervous system moves into low, resting, gear, stress hormones drop to their lowest levels, and our immune system reboots. Our cognitive and psychological health benefits from the memory processing, the hormone production and regulation, and the cellular renewal that all take place during sleep.
When we don’t get enough consistent, high-quality sleep, we miss out on the full impact of sleep’s deeply restorative powers. Poor sleep increases inflammation, which is a powerful driver of biological aging and a significant factor in age-related disease, from heart disease to cancer to neurodegenerative diseases. Poor sleep—even a single night of it—appears to directly affect the aging of our cells and increase the activity of genes that drive cellular aging.
We still have so much to learn about how sleep can affect aging. One area of research that’s received a lot of attention over the past decade is the relationship between sleep and a significant marker of biological age: telomere length.
If you haven’t heard of telomeres, you’re not alone. Telomeres are DNA material found within our cells, and the condition of telomeres—specifically, the length of telomeres–can provide important indications about our biological age. As a growing body of research shows, there are strong links between telomeres and sleep.
What are telomeres?
Telomeres are structures of DNA that sit at the ends of our chromosomes. Chromosomes, as you’ll recall from high school biology, are strands of bundled up DNA found inside our cells. Chromosomes help to ensure that DNA is passed along correctly as cells divide and replicate, making new cells to replace old cells that have worn out their useful lifespan.
Telomeres function as a protective cap for chromosomes, helping to avoid damage to DNA and to keep DNA information intact.
Telomeres are an important marker for biological age. Here’s why.
When cells divide and replicate, the telomeres at the end of our chromosomes divide, too. Over time, telomeres become shorter. Shorter telomeres offer less protection for the DNA within our chromosomes and contribute to the aging of cells. Shorter telomere length is associated with higher mortality risks, and with greater risks for chronic and serious disease, including cardiovascular disease, type 2 diabetes, Alzheimer’s disease, and cancer.
Telomeres shorten gradually as we age. But there are a range of factors that appear to influence telomere length, either accelerating the shortening of telomeres, or helping to preserve their length over time. These factors include:
- Weight and BMI (obesity, and larger waist circumference, are linked to shorter telomere length)
- Physical activity levels
- Lifestyle habits, including smoking
Sleep is another factor that appears to have significant influence over the length of telomeres.
The relationship between sleep and telomere length
When we talk about sleep, we’re talking about a whole range of elements that comprise our sleep, including how much we sleep, how well we sleep, when we sleep, how consistent our sleep schedules are, how aligned our sleep-wake patterns are with our chronotype. All of these factors—and the presence of clinical sleep disorders—appear to affect telomere length.
Sleep duration. A growing body of research has shown links between sleep duration—the amount of sleep we get at night—and telomere length. Broadly speaking, longer sleep has been associated with longer telomere length, in a number of different populations, including people with and without chronic health conditions, in both men and women, and across different age groups.
A 2019 study examined data from the Women’s Health initiative on more than 3,000 post-menopausal women and found that every hour of additional sleep beyond 5 hours, telomere length was significantly longer. The researchers found that on average, women who slept less than 7 hours a night had telomere length that was equivalent to women who were 2 years older.
Some research has also found that shorter sleep duration is linked to shorter telomeres in children.
Age as a factor in the relationship between sleep and telomere length is one of the big questions that scientists are examining closely. Some studies of mixed-age populations suggest the relationship between sleep and telomere length may be different at different points across our lifespan. For example, one study found that longer sleep duration was linked to longer telomere length in women younger than 50, but not in women older than 50. Other recent research found that longer sleep duration was associated with “younger” telomeres among older adults, but found no relationship between sleep duration and telomere length in middle-aged adults. And this 2016 study found that insomnia was linked to shorter telomeres in older adults (aged 70-88), but not in adults younger than 70.
Sleep quality. In most of the studies that have investigated links between sleep quality and telomere length, scientists have found that poor sleep quality is associated with shorter telomere length. These studies include groups of men and women, and both middle aged and older adults.
However, some research has reported finding no link between sleep quality and telomere length, even while finding an association between sleep duration and telomere length.
In some (but not all) of the research that looks at sleep quality and telomere length, the participants’ sleep quality is measured by taking information from the sleepers themselves. This self-reported sleep data is subjective—it’s a self-assessment, rather than an objective measurement. Self-reported data is valuable, but one of the ways we will come to a stronger understanding of the relationship between sleep and telomeres is by more research that evaluates that relationship using objective measurements of sleep quality, including time spent in the different stages of sleep, and the number of awakenings that take place throughout the night.
Sleep timing, circadian rhythms, and chronotype. This particular area of research of the sleep-telomere relationship hasn’t gotten a lot of attention, to date. But it’s an important one, where I hope we’ll see some real focus in future studies. There is some preliminary evidence that later bedtimes and delayed circadian rhythms may be associated with shorter telomere length. Delayed circadian rhythms are individual rhythms that are out of sync and tilt significantly toward wakefulness later into the evening. Delayed circadian rhythms are common in people of all different chronotypes, thanks to factors such as stress, overloaded daily schedules, and excessive and prolonged nighttime exposure to artificial light.
This 2019 study from The Netherlands found that delayed circadian rhythms were strongly linked to shorter telomere length, over a 6-year study period. Late sleep onset—falling asleep later in the evening—was also linked to shorter telomeres. The researchers found some interesting and potentially important information about chronotype. In this study, late chronotype in adulthood was linked to shorter telomeres, over the 6-year timeframe. (Late chronotypes are those with a biological preference for evenings, the Wolves among us.) In assessing chronotype, the study found that very early chronotype was linked to less reduction in telomere length, compared to intermediate (aka, middle of the road) chronotype.
Sleep apnea and other sleep disorders. There is a strong emerging connection between shorter telomeres and obstructive sleep apnea, a serious sleep disorder that is characterized by episodes of interrupted breathing and significantly fragmented sleep. OSA itself is strongly linked to higher mortality risks, accelerated biological aging, and risks for serious disease, including cardiovascular disease, type 2 diabetes, and cancer. OSA deprives us of sound sleep, reduces the body’s supply of oxygen, elevates inflammation and oxidative stress, which contribute to the aging and dysfunction of our cells.
This 2019 study of 672 men and women (ages 44-84) found OSA was linked to significantly shorter telomeres. When scientists compared telomere length in people with severe OSA to people without sleep apnea, they found a dramatic difference: People with severe OSA had telomeres that indicated, on average, a 10-year acceleration of cellular aging.
A number of studies have also found links between insomnia and telomere length. In some research, the connection between insomnia and shorter telomeres has appeared only in older adults, age 70 and older. But we don’t know nearly enough yet about this relationship to know whether older adults are uniquely vulnerable.
Given what we know, to date, about the associations between sleep quantity, sleep quality and telomere length, it is not surprising to see serious sleep disorders linked to accelerated shortening of telomeres.
What does this research mean for you? Telomeres offer vital protection to our cells over our lifespan. The connections between telomere length and sleep are a powerful indication of the role sleep plays in longevity. We know sleep is an important factor in longevity and helps to slow the pace of biological aging. But we are still at the relatively early stages of understanding exactly how sleep affects the biological mechanisms of aging, including the aging of our cells.
What you can do
Meet your sleep needs, consistently. Most adults need between 7-9 hours of sleep a night. Individual sleep needs vary. But most adults aren’t getting sufficient rest on a routine basis. Use my bedtime calculator to determine the sleep routine that fits your daily schedule, and stick to it, night after night.
Ensure your rest is…actually restful. It’s not just the duration of your sleep but the quality that matters to longevity. Practice the fundamentals of sleep hygiene: sleeping on a consistent schedule, setting limits on caffeine, sugar, and alcohol, tending to stress, setting up a bedroom that supports your healthy rest, and keeping that bedroom clean to optimize your sleep.
Address any potential sleep disorders. The associations between telomere length and OSA are preliminary, but suggest that there’s a real connection between the two. For health in the here and now and longevity down the road, don’t wait to talk with your health care provider about any issues you’re having with your sleep. Remember, problems with daytime energy levels, productivity, and performance can often be signs of a sleep disorder that’s undiagnosed.
Beyond sleep, there are other lifestyle habits and strategies that are associated with preserving the length of telomeres. Integrating these practices to your daily life will also help your sleep.
Exercising regularly. Regular exercise is associated with longer telomeres, and it’s an association that appears to become more significant with age. Making exercise part of your daily routine and working to keep daily exercise a part of your life over the long-term is an important investment in longevity—and sleep.
Maintain a healthy weight. Obesity has been strongly linked to shorter telomeres. There’s promising research showing that losing weight may lengthen telomeres.
Eating for longevity. Studies show that diets that emphasize vegetables, beans, whole grains, nuts, seaweed, fish and seafood, and limit sugar, meat, and processed foods are associated with longer telomeres. These dietary habits align with the foods that are most helpful to sleep.
Sleep is far more than a tool to elevate your productivity and your quality of life in the here and now. It is also an investment in your long-term future, your health and well being for years to come. This research reveals how deeply your sleep, on a nightly basis, can affect your biology at the cellular level. That knowledge is worth taking to heart and putting into practice, making your sleep a top priority.
Michael J. Breus, PhD, DABSM
The Sleep Doctor™