New mothers often joke that the lack of sleep they get during those first months with their newborn has taken years off their life. New research from UCLA suggests that joke may have some truth to it.
In a recent study of 33 new moms in the Los Angeles area, UCLA researchers found the biological age of women losing sleep in the first year after giving birth increased more than that of women who slept enough.
It's the first study to show biological aging in new moms, according to first author Judith Carroll, UCLA's George F. Solomon professor of psychobiology.
What Are Biological Age and Epigenetics?
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A person's "biological age," or epigenetic age, can be different from their regular chronological age.
Epigenetics, according to the CDC, is the study of how your environment, your behaviors, and the things you've experienced change the way your genes are expressed.
The DNA sequence, the genetic code of who you are, is not reordered. But your body may read that sequence differently based on the unique factors you experience, turning pieces of that genetic code "on" or "off."
It's the same natural process used by genes to decide whether a cell is a muscle, heart or nerve cell, the CDC says. The parts of the genetic code that make proteins in a muscle cell are turned on when your body grows muscles, while that same cell's genes will turn off the code used to grow a nerve cell.
As people age, different genes turn on and off over time.
"The process of biological aging is something that occurs over a lifetime," Carroll said, changing due to different factors that could range from UV exposure to diet. The process is seen to be a key factor for diseases that occur with age, she added.
That pattern of changes can also estimate how old a person is biologically, through methods like the algorithm designed by Steve Horvath, a professor of biostatistics at UCLA and co-author in the study.
The age estimates led UCLA researchers to conclude the sleep deprived new moms in their study were biologically older than moms who got enough sleep.
How Did Sleep Affect New Moms' Ages?
The researchers split the 33 participants into two groups. One got at least the CDC recommended amount of sleep each night, seven hours or more. The other group got between five and six-and-a-half hours of sleep each night.
Blood samples were taken from those mothers, and researchers used the blood to estimate the biological age of the participants.
The researchers found, one year after giving birth, the biological age of the sleep deprived new mothers was between three and seven years older than their chronological age.
The mothers participating in the study were between 23 and and 45 years old, and the effect was independent of their chronological age, Carroll said.
Those mothers also had shorter telomeres, "small pieces of DNA at the ends of chromosomes act as protective caps," in their white blood cells, a UCLA news release said. Shorter telomeres are "linked to a higher risk of cancers, cardiovascular and other diseases, and earlier death."
The period of time right after having children is known for lacking in good sleep, Carroll said. Her own experience and anecdotal evidence from her friends with children "was one of the bigger factors" leading to the research, as did her interest in the role of sleep in health.
"I have definitely lived through that, and thought it might have a pretty big impact biologically," she added.
She teamed up with co-author Christine Dunkel Schetter, professor of psychology and psychiatry who leads the Stress Processes and Pregnancy Lab at UCLA.
This study and others on postpartum mental health should incentivize support for new mothers so they can get enough sleep, Schetter said. That includes methods such as "parental leave so that both parents can bear some of the burden of care, and through programs for families and fathers," she said in the release.
What Do The Results of This Study Mean?
This study alone can't definitively state the link between sleep and aging in moms.
"It’s the first study, with a really small sample [size]," Carroll said. "We need to replicate this before we take it to the bank."
The study also can't explain whether the increase in biological age can be reversed.
"We don’t want the message to be that mothers are permanently damaged by infant care and loss of sleep," Schetter said in the release. "We don't know if these effects are long lasting."
Even so, the study moves sleep research into new territory. Future studies could look at how sleep deprivation affects fathers and others losing sleep to care for children, and at the social factors preventing moms from getting enough sleep now.
It also matches general findings from previous sleep research, which suggest less than seven hours of sleep each night has negative health effects.
"Sleep is important for overall health, and it needs to be considered as part of one of those lifestyle factors," just like exercise and diet, Carroll said.
That may be difficult for moms who work early shifts, work two jobs, or can't catch a break, which the authors recognize. But if they can, new moms should try and get as much sleep as possible, she emphasized. Sleep while the baby is sleeping, take naps when the moment comes, and ask family members to help if those moments aren't materializing.
"These are things that are really just critical that we can adjust societally" to make life for new mothers easier, Carroll said. In the meantime, "if they’re feeling like they need more sleep, look for opportunities to sleep."