Resume: Not getting enough sleep can negate the cognitive benefits of regular exercise.
Researchers studied cognitive function over 10 years in nearly 9,000 English people aged 50 and older. They found that those who were physically active but slept less than six hours had faster cognitive decline.
Therefore, after ten years, their cognitive function resembled less physically active peers.
- The study showed rapid cognitive decline in physically active individuals in their 50s and 60s who slept less than six hours a night.
- For older participants (70 years and older), the cognitive benefits of exercise were maintained despite short sleep.
- The findings highlight the importance of considering sleep and physical activity together for cognitive health.
Regular physical activity may protect against cognitive decline as we age, but this protective effect may decrease for people who don’t get enough sleep, according to a new study by UCL researchers.
The study, published inThe Lancet Healthy Longevity, looked at cognitive function over 10 years in 8,958 people aged 50 and over in England. The research team investigated how different combinations of sleep and exercise habits can affect people’s cognitive function over time.
They found that people who were more physically active but had short sleep — less than six hours on average — generally showed faster cognitive decline, meaning that after 10 years their cognitive function was similar to peers who were less physically active.
Lead author Dr Mikaela Bloomberg (UCL Institute of Epidemiology & Health Care) said: “Our study suggests that we may need adequate sleep to reap the full cognitive benefits of physical activity. It shows how important it is to consider sleep and physical activity together when thinking about cognitive health.
“Previous studies examining how sleep and physical activity can be combined to influence cognitive function have been mostly cross-sectional – focusing only on a snapshot – and we were surprised that regular physical activity is not always enough to counteract the long-term effects. .of sleep deprivation on cognitive health.”
The study found, in line with previous research, that sleeping between six and eight hours per night and higher levels of physical activity were associated with better cognitive function.
Those who were more physically active also had better cognitive function, regardless of how long they slept at the start of the study. This changed over the 10-year period, with more physically active short sleepers (less than six hours) experiencing faster cognitive decline.
This rapid decline was true for the over-50s and over-60s in this group, but for older participants (aged 70 and older), the cognitive benefits of exercise seemed to be maintained despite short sleep.
Co-author Professor Andrew Steptoe (UCL Institute of Epidemiology & Health Care) said: “It is important to identify the factors that may protect cognitive function in middle age and later in life, as they may serve to extend our cognitively healthy years. and, for some people, delay a diagnosis of dementia.
“The World Health Organization already identifies physical activity as a way to maintain cognitive function, but interventions should also consider sleep habits to maximize long-term benefits to cognitive health.”
For the study, the researchers used data from the English Longitudinal Study of Aging (ELSA), a nationally representative cohort study of the English population.
Participants were asked how long they slept on an average weeknight and were split into three sleep groups: short (less than six hours), optimal (six to eight hours), and long (more than eight hours).
They were also scored based on the frequency and intensity of self-reported physical activity and divided into two groups: more physically active (the top third of the scorers) and less physically active (the other two thirds).
Cognitive function was assessed based on an episodic memory test (asking participants to recall a list of 10 words, both immediately and with a delay) and a verbal fluency test (asking participants to name as many animals as possible in one minute). .
The researchers adjusted for a number of confounding factors, such as participants who have previously taken the same cognitive test and are therefore likely to perform better.
They also excluded people with self-reported dementia diagnoses and those whose test scores indicated cognitive impairment, so that behavioral changes associated with preclinical Alzheimer’s disease (such as sleep disturbances) did not inadvertently affect the results.
In terms of study limitations, the researchers relied on participants self-reporting their sleep duration and physical activity. The next steps, the researchers said, may be to replicate the results in more diverse study populations, examine more cognitive domains and more domains of sleep quality, and use objective measures such as a wearable physical activity tracker.
financing: The research was funded by the UK Economic and Social Research Council.
About this news about movement, sleep and cognition research
Author: Mark Greaves
Contact: Mark Greaves – UCL
Image: The image is credited to Neuroscience News
Original research: Open access.
“Joint Associations of Physical Activity and Sleep Duration with Cognitive Aging: Longitudinal Analysis of an English Cohort Study” by Mikaela Bloomberg et al. Lancet healthy longevity
Joint associations of physical activity and sleep duration with cognitive aging: longitudinal analysis of an English cohort study
Physical activity and sleep duration are key factors associated with cognitive function and dementia risk. How physical activity and sleep interact to influence cognitive aging has not been well studied. We aimed to examine the associations of combinations of physical activity and sleep duration with 10-year cognitive trajectories.
In this longitudinal study, we analyzed data from the English Longitudinal Study of Aging collected between January 1, 2008 and July 31, 2019, with follow-up interviews every 2 years. Participants were cognitively healthy adults aged at least 50 years at baseline. Participants were asked about baseline physical activity and nighttime sleep duration. At each interview, episodic memory was assessed using immediate and delayed recall tasks and verbal fluency using an animal naming task; scores were standardized and averaged to produce a composite cognitive score. We used linear mixed models to examine independent and joint associations of physical activity (lower physical activity or higher physical activity, based on a score that accounts for frequency and intensity of physical activity) and sleep duration (short duration). [<6 h]optimal [6–8 h]or long [>8 h]) with cognitive performance at baseline, at 10 years of follow-up, and rate of cognitive decline.
We included 8958 respondents between 50 and 95 years of age at baseline (median follow-up 10 years [IQR 2–10]). Lower physical activity and suboptimal sleep were independently associated with poorer cognitive performance; short sleep was also associated with faster cognitive decline. At baseline, participants with higher physical activity and optimal sleep had higher cognitive scores than all combinations of lower physical activity and sleep categories (e.g., difference between those with higher physical activity and optimal sleepin return forthose with lower physical activity and short sleep at baseline age of 50 was 0.14 SDs [95% CI 0·05–0·24]). We found no difference in baseline cognitive performance between sleep categories within the higher physical activity category. Those with more physical activity and short sleep had faster cognitive decline than those with more physical activity and optimal sleep, so their scores at 10 years were proportional to those who reported low physical activity, regardless of sleep duration (e.g., cognitive performance at 10 years follow-up). -up between those with more physical and optimal sleep and those with lower physical activity and short sleep was 0.20 SDs [0·08–0·33]; the difference between those with more physical activity and optimal sleep and those with less physical activity and short sleep was 0.22 SDs [0·11–0·34]).
The cognitive benefit at the onset of more frequent, higher-intensity physical activity was insufficient to ameliorate the more rapid cognitive decline associated with short sleep. Exercise interventions should also consider sleep habits to maximize the long-term benefits of exercise for cognitive health.
British Economic and Social Research Council.
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