Good sleep quality and good mood lead to good working memory with age
May 11, 2019
Science Daily/University of California - Riverside
A team of psychologists has found strong associations between working memory -- a fundamental building block of a functioning mind -- and three health-related factors: sleep, age, and depressed mood. The team also reports that each of these factors is associated with different aspects of working memory.
Working memory is the part of short-term memory that temporarily stores and manages information required for cognitive tasks such as learning, reasoning, and comprehension. Working memory is critically involved in many higher cognitive functions, including intelligence, creative problem-solving, language, and action-planning. It plays a major role in how we process, use, and remember information.
The researchers, led by Weiwei Zhang, an assistant professor of psychology at the University of California, Riverside, found that age is negatively related to the "qualitative" aspect of working memory -- that is, how strong or how accurate the memory is. In other words, the older the person, the weaker and less precise the person's memory. In contrast, poor sleep quality and depressed mood are linked to a reduced likelihood of remembering a previously experienced event -- the "quantitative" aspect of working memory.
"Other researchers have already linked each of these factors separately to overall working memory function, but our work looked at how these factors are associated with memory quality and quantity -- the first time this has been done," Zhang said. "All three factors are interrelated. For example, seniors are more likely to experience negative mood than younger adults. Poor sleep quality is also often associated with depressed mood. The piecemeal approach used in previous investigations on these relationships -- examining the relationship between one of these health-related factors and working memory -- could open up the possibility that an observed effect may be influenced by other factors."
The researchers are the first to statistically isolate the effects of the three factors on working memory quantity and quality. Although all three factors contribute to a common complaint about foggy memory, they seem to behave in different ways and may result from potentially independent mechanisms in the brain. These findings could lead to future interventions and treatments to counteract the negative impacts of these factors on working memory.
Research results appear in the Journal of the International Neuropsychological Society.
The researchers performed two studies. In the first study, they sampled 110 college students for self-reported measures of sleep quality and depressed mood and their independent relationship to experimental measures of working memory. In the second study, the researchers sampled 31 members of a community ranging in age from 21 to 77 years. In this study, the researchers investigated age and its relationship to working memory.
"We are more confident now about how each one of these factors impacts working memory," Zhang said. "This could give us a better understanding of the underlying mechanism in age-related dementia. For the mind to work at its best, it is important that senior citizens ensure they have good sleep quality and be in a good mood."
https://www.sciencedaily.com/releases/2019/05/190511083929.htm
Sleeping Well at 100 Years of Age: The Secrets to Healthy Longevity
May 2, 2010
Science Daily/American Academy of Sleep Medicine
A study in the May 1 issue of the journal Sleep is the first to examine sleep issues in a large sample of exceptionally old adults, including nearly 2,800 people who were 100 years of age and older.
Results show that about 65 percent of the sample reported that their sleep quality was good or very good, and the weighted average daily sleep time was about 7.5 hours including naps.
Surprisingly, the oldest adults aged 100 and above were 70 percent more likely to report good sleep quality than younger participants aged 65 to 79, after controlling for variables such as demographic characteristics, socioeconomic status and health conditions. Men were 23 percent more likely than women to report sleeping well.
Adults aged 80 and over tended to have a sleep duration that was either shorter or longer than adults aged 65 to 79, which was primarily due to deteriorating health. Controlling for health conditions showed that participants who were 100 years of age and older were less likely than the youngest elders to sleep for five or fewer hours per day, but they were almost three times more likely to sleep for 10 hour or more.
http://www.sciencedaily.com/releases/2010/05/100501013521.htm
Healthy Adults May Need Less Sleep as They Age
February 2, 2010
Science Daily/American Academy of Sleep Medicine
A study in the Feb. 1 issue of the journal Sleep suggests that healthy older adults without sleep disorders can expect to have a reduced "sleep need" and to be less sleepy during the day than healthy young adults.
Results show that during a night of eight hours in bed, total sleep time decreased significantly and progressively with age. Older adults slept about 20 minutes less than middle-aged adults, who slept 23 minutes less than young adults. The number of awakenings and the amount of time spent awake after initial sleep onset increased significantly with age, and the amount of time spent in deep, slow-wave sleep decreased across age groups. Yet even with these decreases in sleep time, intensity and continuity, older adults displayed less subjective and objective daytime sleep propensity than younger adults.
Furthermore, two additional nights involving experimental disruption of slow-wave sleep led to a similar response in all age groups. Daytime sleep propensity increased, and slow-wave sleep rebounded during a night of recovery sleep. According to the authors, this suggests that the lack of increased daytime sleepiness in the presence of an age-related deterioration in sleep quality cannot be attributed to unresponsiveness to variations in homeostatic sleep pressure. Instead, healthy aging appears to be associated with reductions in the sleep duration and depth required to maintain daytime alertness.
"Our findings reaffirm the theory that it is not normal for older people to be sleepy during the daytime," said principal investigator Derk-Jan Dijk, PhD, professor of sleep and physiology at the University of Surrey in the U.K. "Whether you are young or old, if you are sleepy during the day you either don't get enough sleep or you may suffer from a sleep disorder."
The study was conducted at the Clinical Research Centre of the University of Surrey and involved 110 healthy adults without sleep disorders or sleep complaints; 44 were young (20 to 30 years), 35 were middle-aged (40 to 55 years) and 31 were older adults (66 to 83 years). After an eight-hour baseline sleep test, subjects were randomized to two nights with or without selective slow-wave sleep disruption by acoustic stimuli, followed by one recovery night. Nighttime sleep was evaluated by polysomnography, while sleep propensity was assessed using the Multiple Sleep Latency Test (MSLT) and the Karolinska Sleepiness Scale.
During the baseline night, mean objective total sleep time decreased from 433.5 minutes for young adults to 409.9 minutes for middle-aged adults and 390.4 minutes for older adults. Average minutes of slow-wave sleep decreased from 118.4 minutes for young adults to 85.3 minutes for middle-aged adults and 84.2 minutes for older adults. Mean number of minutes spent awake after initial sleep onset increased from 21 for young adults to 49.9 for middle-aged adults and 70.7 for older adults.
Objective daytime sleepiness measured by the MSLT decreased with age. When asked to lie in a comfortable position on the bed and try to fall asleep, young adults fell asleep in an average of 8.7 minutes, compared with 11.7 minutes for middle-aged adults and 14.2 minutes for older adults.
The authors noted that the cause of the age-related reductions in slow-wave sleep and sleep need still must be established. Related factors could include alterations in reproductive hormones or changes in the brain. They added that the study did not address sleep propensity during the evening hours, when it is possible that older adults may be sleepier than young adults.
According to the authors, the study also has implications for the treatment of insomnia in older adults, who may be unaware of their reduced sleep need. Therefore, sleep restriction, which leads to increased homeostatic sleep pressure, may be a successful behavioral therapy for insomnia in healthy older adults.
http://www.sciencedaily.com/releases/2010/02/100201091632.htm