A study found that people who regularly get together with friends and family reduce their risk of early death, in other words, people who get together regularly with their loved ones live longer on average. On the other hand, people who never get visited by friends or family members were found to be at greater risk of early death, even if they live with their families. The results suggest that some social connections have a greater impact on health than others.
There were previous studies that found that social isolation had a negative impact on health or that examined the relationship between social connections and the risk of death. However, there was little information about the impact of connections on life expectancy. Hamish Foster and his team at the University of Glasgow in the United Kingdom collected data on socialization and loneliness from more than 450,000 people aged 38-75 living in the UK. The individuals completed a one-time physical health assessment form and a survey measuring five different types of social connections between 2006 and 2010. The survey asked how often they felt lonely, confided in someone close, were visited by friends or family, and attended weekly group activities. It also asked whether the participants lived alone. The researchers then followed up with the participants to determine how many had died as of 2021.
After adjusting for factors such as age, gender, physical activity level, socioeconomic status, and chronic health conditions during the statistical analysis, the researchers determined that all five types of social connections affected life expectancy. Visits from friends and family were found to have the greatest effect. On average, people who were never visited by friends or family had a 39 percent higher risk of death during the study period than those who were visited daily by loved ones. The findings found that even those who did not live alone had a 25 percent higher risk of death during that time period if they were not visited by family or friends. Participating in weekly group activities did not eliminate this effect.
The fact that the effect is valid even for those who do not live alone is thought to be related to relationship quality. For example, for someone who does not live alone, if the relationship quality with the person they live with is low, being visited by loved ones may become even more important on their life expectancy. On the other hand, there was no difference in the risk of death during the time period in which the study was conducted between being visited by loved ones monthly, weekly or daily. Therefore, according to the researchers, even monthly visits may be sufficient to reduce this risk.
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Is 8 Hours of Sleep Necessary for a Healthy Brain?
Extensive animal studies have shown that at night, the brain's cleaning system speeds up, clearing it of toxic compounds linked to Alzheimer's disease, such as beta-amyloid. Studies of large groups have also found that people whose sleep durations are unusually short or long have worse health outcomes, including memory loss and brain shrinkage, a hallmark of Alzheimer's. Studies have only been able to identify correlations between sleep duration and health, but it has not been possible to say whether insufficient sleep causes a health problem. Such data could be obtained through a randomized study, but it would be almost impossible to do so because not many people would be willing to change their sleep habits for any length of time in the name of science, says Anders Fjell of the University of Oslo in Norway.
It shows that the brain's cleansing system is buffed, thus removing toxic compounds linked to Alzheimer's disease, such as beta-amyloid. Studies on large groups have shown that people with unusually short sleep durations also experience health problems such as memory loss and brain shrinkage, one of the hallmarks of Alzheimer's. It has been determined that worse conditions including Studies can only detect correlations between sleep duration and health, but it cannot be said whether insufficient sleep causes a health problem. Anders Fjell of the University of Oslo, Norway, said such data could be obtained in a randomized trial, but there are not many people willing to change their sleep habits for any length of time in the name of science.
Fjell and his team have now sought to investigate further with a series of studies using brain volume as a parameter for brain health. First, they looked at brain volume in relation to sleep duration over time, using existing data from about 47,000 people. Here, the highest brain volume was associated with 6.5 hours of nightly sleep. The team then conducted another analysis, following nearly 4,000 people for up to 11 years. In this case, there was no connection between sleep duration at the beginning of the study and brain shrinkage during this time. Fjell says the result in the first analysis could be explained by brain shrinkage causing sleep disruption, or alternatively, people with naturally smaller or larger brains, for example, may tend to sleep less for an unknown reason.
The researchers also conducted a third analysis of nearly 30,000 people using genetic data collected in one of the studies. This analysis revealed that those who were genetically predisposed to short or long sleep durations did not have smaller brain volumes compared to those who slept for more normal durations. Taken together, these results challenge the idea that not getting enough sleep shrinks the brain, Fjell says.
Although Fjell does not recommend that anyone deliberately change their sleep habits as a result of the findings, he does believe that there is a lot of natural variation in people's innate sleep needs and that—as long as conditions allow—the brain will make sure that "enough sleep is being had." In other words, he thinks that we have a homeostatic drive for needed sleep.
The team's conclusions are unlikely to convince everyone. The key measure of brain health is neuron density, not total brain volume, says Matthew Walker, a professor of neuroscience and psychology at the University of California at Berkeley, who recommends that people get 8 hours of sleep a night. Walker also notes that the most important measure of sleep quality is not the total amount of sleep people get, but rather how much time they spend in deep sleep, when brain waves are slowed down. Walker's view also supports the discovery of a waste-clearing system in the brain called the glymphatic system by neuroscientist Maiken Nedergaard of the University of Rochester, New York. Clearance of amyloids in the brain is intensified during deep sleep.
However, Fjell points out that deep sleep usually occurs in the first four hours of the night. He also emphasizes that it is not clear whether more sleep would make this cleansing process easier. Nedergaard says the study is significant because of the finding that greater brain volume is associated with just 6.5 hours of sleep per night. What is surprising is that the optimal sleep duration is currently shorter than recommended.