A single bad night’s sleep may be easier on a healthy older brain than a younger one, though regularly missing sleep still carries risks.
Sleep quality often declines with age, yet older adults can seem less affected by a single bad night than younger people. Understanding that apparent mismatch means looking at how the brain responds when sleep runs short.
A study from Simon Fraser University offers a possible explanation. After just three hours of sleep, certain connections in younger and older brains changed in opposite directions. The findings suggest that healthy older brains may adapt to acute sleep loss in ways that help preserve function, although the study measured brain activity rather than cognitive performance.
The research, published in Imaging Neuroscience, compared brain networks in younger adults ages 20 to 30 with those in older adults ages 65 to 75. Lead researcher Josh Neudorf, an affiliate member of SFU’s Institute for Neuroscience and Neurotechnology, says earlier research on the effects of poor sleep provided a reason to investigate the difference.
“Older adults tend to better handle the effects of poor sleep, whereas younger adults, as we know, have the common symptoms of decreased mood and cognitive ability following poor sleep,” says Neudorf.
“This study tries to get at the heart of this difference – how does the older brain react to lost sleep.”
How brain networks handle a short night
Brain connectivity describes how activity in different regions is linked. Stronger connections do not automatically mean the brain is working more efficiently. The arrangement matters, too. In a more modular network, regions are organized into groups, with relatively stronger connections within each group than between groups.
“What we found was quite striking in that older and younger brains actually responded in opposite ways to acute sleep loss.
“Certain connections in the brains of younger adults showed increased connectivity as a response to less sleep, while those same connections in the brains of older adults showed decreased connectivity.
“That decrease in connectivity promotes more efficient modular connectivity for the brain as a whole. In other words, the brain is acting in a more efficient way to maintain cognitive function. In contrast, the increased connectivity in younger brains suggests the brain is having to work harder to maintain function.”
Whether those network changes actually helped the older participants think or perform tasks better was not tested. The proposed benefit is an interpretation of the brain activity, consistent with previous research suggesting that older adults are often less impaired by a single night of poor sleep.
The reason for the opposite responses also remains open. One of several possible explanations is compensation, in which an aging brain reorganizes its networks and uses different strategies to maintain function.
“The quality of sleep starts to change and deteriorates somewhat in older adults,” says Neudorf.
“The theory of compensation is the idea that older brains adapt or compensate for those changes.”
Chronic sleep loss still harms health
Being able to adjust to an occasional short night would not make regularly missing sleep harmless. Researchers emphasize that good-quality sleep matters throughout life. Although the response to one or two nights of lost sleep may differ with age, chronic sleep loss is detrimental to brain health and cognitive ability. Its cumulative effects over a lifetime also have the potential to increase the risk of cardiovascular disease, hypertension, diabetes, weight problems, and colorectal cancer.
Dementia presents another concern. Study co-author Brianne Kent is an assistant professor of psychology, associate director of SFU’s Institute for Neuroscience and Neurotechnology, and Canada Research Chair in Translational Neuroscience and Dementia. Her research focuses on Alzheimer’s disease, the most common cause of dementia.
“A lot of sleep disruption could increase your risk of dementia,” says Kent.
“What we know is that there’s a protein called amyloid beta, which accumulates in the brain and causes these plaques in the brains of individuals who have dementia. Amyloid beta is this toxic protein, a waste product of your brain. These plaques accumulate for, on average, about 20 years before dementia starts.”
Sleep plays a role in how quickly that protein is removed, linking repeated sleep loss to a process that can unfold over decades.
She concludes, “During sleep, that protein is cleared out at a faster rate. So if you’re continuously missing sleep, then that protein and those plaques will accumulate at a faster rate. Not everyone who has poor sleep will get Alzheimer’s disease, but if you are somebody who has the predisposition for the disease, then missing sleep over time will drive the process.”
Reference: “Young and old adult brains experience opposite effects of acute sleep restriction on the functional connectivity network” by Josh Neudorf, Leanne Rokos, Kelly Shen, Brianne Kent and Anthony R. McIntosh, 18 June 2026, Imaging Neuroscience.
DOI: 10.1162/IMAG.a.1278
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