A radioactive bunker in the bowels of the hospital
August 24, 2022Call for Aid for the Financing of Feasibility Studies of Health Innovations_ 2022
August 26, 2022
The work analyzed the evolution of 150.000 65-year-old people over a decade. Other less passive behaviors, such as using the computer, are instead associated with better mental health
Tracking hundreds of thousands of older people shows that those who watch more television are more likely to suffer from dementia. However, the same does not happen if what they do is use the computer, a less passive mental behavior. This research, which highlights the benefits of physical activity, shows that being sedentary is not bad for the brain in itself: it depends on what you do while sitting.
Science has accumulated enough tests that connect mental health with physical activity, especially when cognitive decline lurks as we age. In the same way, lack of exercise favors the appearance of coronary heart disease. among the most sedentary. But the connection between a sedentary lifestyle and dementia has not yet been established categorically. Now, one of the largest studies conducted to date looks at this relationship.
Researchers from several universities in the United States have compared the mental health status of 146.651 seniors when they had an average age of 64,5 years with their situation a decade later. In that period, 3.507 of them (about 2,5%) were diagnosed with dementia. The study participants, obtained from an impressive public health tool (the British database UK Biobank) completed a series of questionnaires to find out their physical activity and the time they spent sitting, either watching television or in front of the computer (excluding working hours).
Sports and seniors
The results of the comparison, recently published in the scientific journal (PNAS), show that once other variables are controlled (sex, previous illnesses, smoking, work, age, etc.), physical activity appears related to a lower probability of developing any type of dementia. The result confirms previous studies that have linked sport and mental health also in the elderly. In April, for example, a job with several thousand Americans showed how physical exercise appeared related to a lower incidence of Alzheimer's. But that research also mentioned performing demanding cognitive tasks as part of a diet for good brain aging.
The strong point of this new study is that it reveals a consistent relationship between a sedentary lifestyle and mental health, but not just any sedentary lifestyle. The questionnaires asked participants how many hours a day they spent watching television or in front of a computer screen. What they have observed is that the more time spent sitting in front of the television, the greater the likelihood of having dementia after a decade of follow-up. The percentage increase in risk rises to 40%. But the same does not happen with computers: the probability of developing dementia in this case drops to 20%.
David Raichle researches the impact of physical activity on human health and well-being at the University of Southern California and is the lead author of the study published in (PNAS). Raichlen emphasizes that it is no longer worth condemning a sedentary lifestyle without differentiating what one is doing, even if one is sitting. But he also recognizes that it is not easy to know why the computer is better than television. “We know that cognitive demand can have benefits for the brain, and it is possible that computer use during leisure time is cognitively demanding in a way that offsets the risks of sitting too much,” he says in an email.
To confirm this, adds Raichlen, “both a more detailed investigation of the mechanisms and the design of interventions to determine causal relationships” would be needed, since their study “can only really detect associations.” The relationship between a sedentary lifestyle and lower energy consumption and muscle metabolism is evident, but it is not so easy to know how it affects cognitive deterioration beyond the metaphor of training the brain.
Neutralize the TV
A few weeks ago, neuroscientists from German Center for Neurodegenerative Diseases They published the partial results of a work still in progress. They performed brain imaging on 2.500 people wearing an accelerometer to record their physical activity. They found that those who performed more physical exercise tended to have greater volume in critical areas such as the hippocampus, the memory control unit. Although the sample included adults under 65 years of age, the protective mantle of sport was more marked in those over 70 years of age.
The researchers of this work also investigated the relationship between physical activity and sedentary lifestyle (television or computer). They wanted to know if the first modulated or reduced the risk caused by the second. Taking as a reference the group of people with greater physical activity and less time in front of the television, they saw a clear pattern in which those who spent more hours watching television had a greater risk of dementia, regardless of the intensity of physical exercise, although it decreased slightly in those who did sports intensively. “We see that physical activity reduces the risk of dementia, but it does not completely neutralize the risks associated with watching television,” Raichlen says.
According to data from the World Health Organization, Alzheimer's and other dementias affect nearly 50 million people worldwide, around 5% of the world's elderly population. Everything indicates that the numbers will increase due to increased life expectancy and aging. The prevalence of different types of dementia, almost negligible among those under 60 years of age, increases with age and explodes among those who reach 85-90 years of age, a group in which half have mental problems. Hence the urgency in determining whether or not there is a healthy sedentary lifestyle for the brain.
Different sedentary lifestyles
For neuropsychologist David Bartrés-Faz, professor at the University of Barcelona and associate researcher at the Guttmann Institute, Raichlen's research published in (PNAS) seems very relevant. “This is one of the largest samples following 60-year-old people without dementia for 12 years,” says this expert in mental health and cognitive impairment. What is most important to him is the distinction between different ways of being sedentary. “A sedentary lifestyle had been linked to cognitive decline and increased mortality, but now the relationship is not so clear,” he says. However, what Bartrés-Faz values most about the study is that the protective effect of physical exercise does not affect the risk of dementia from watching so much television. “If you spend hours in front of the television, the risk is not reduced if you then go to the gym for an hour. It's good to go to the gym, but you should also stop watching TV,” recalls the principal researcher at the Barcelona Brain Health Initiative.
However, Bartrés-Faz sees some limitations to the research. The main one is that they did not carry out a baseline study of the cognitive state of each participant at the beginning of the research. And that leads to the risk of reverse causality: “There is the possibility that those who watch more television have greater cognitive impairment or lower skills that make them choose a more passive activity, such as watching television,” she highlights.
The researcher at the Barcelona Biomedical Research Institute (IIBB-CSIC) Coral Sanfeliu is also pleased that we are beginning to differentiate between one type of sedentary lifestyle and another and gives a great example: “Even if you are at the other end of life, “The school is sedentary.” And she agrees with the authors of the research: “Being in front of the computer is not the same as being in front of the television. In the residences, technological tools are already beginning to be taught to combat cognitive decline.” Ella sanfeliu ends the comparison with schoolchildren: “Children who do more physical activity improve their school performance, concentration or their maturation process. You have to combine both things, exercise and an active sedentary lifestyle.”
Fuente: El País
