Are you sitting right now? If you want to protect your brain, you should take a walk and make sure you go to bed early.
Regular exercise and about seven hours of sleep a night could protect brain health in the long term, according to a study published this Wednesday in the journal PLOS One. Long periods of sedentary lifestyle can increase the risk of dementia.
This is the latest data showing that people don’t need elaborate and expensive longevity tricks to maintain mental acuity as they age. According to the study, simple lifestyle changes could reduce a person’s risk of late-onset dementia by up to 25%.
About 1 in 9 people in the United States will develop Alzheimer’s disease, according to the Alzheimer’s Association, meaning a person’s overall risk is about 11%. With the suggested lifestyle changes, the average person’s risk is reduced to about 8%.
The reduction is “quite comparable to the effect size sometimes seen with medications for chronic diseases“said Akinkunle Oye-Somefun, a researcher at York University in Toronto, who led the study.
Breaking up prolonged periods of sitting had the greatest effect, according to the study.
“You don’t have to be perfect, but if you spend a lot of time sedentary during the day, getting a little exercise, even just a walk, will have a long-term benefit for your brain,” said Phillip Hwang, associate professor of epidemiology at Boston University School of Public Health, who was not involved in the study.
The researchers used data from 69 studies that included nearly 3 million people over eight decades. The average age of people in the studies was 67 years old, and they all lived in high-income countries, including the United States.
The studies — which followed people for at least a year, and in some cases up to 11 years — measured how sleeping, sitting and physical activity habits starting at age 35 affected dementia risk later in life. Seventeen of the studies focused on sleep: the sweet spot for brain health was seven to eight hours of sleep each night.
(Study suggests that the use of GLP-1 medications reduces the risk of depression and anxiety)
Sleeping less than seven hours increased the risk of dementia by 18%. Sleeping too much—more than eight hours a night—increased the risk of dementia by 28%.
The rest of the studies in the analysis investigated dementia risk and physical activity or sedentary behavior, such as sitting at work for hours on end. Together, the studies showed that sitting for more than eight hours a day increased the risk of dementia by almost 30%, while staying active regularly, even just taking a walk each day, reduced the risk of dementia by an average of 25%.
Moderate physical activity “offsets dementia risks even when other risk factors are present,” Oye-Somefun said.
Additionally, long periods of sitting can increase a person’s susceptibility to cardiovascular disease, diabetes and obesity, all factors that increase the risk of dementia.
However, “many people assume that physical activity counteracts the harm of sitting for long periods. This is not the case,” Oye-Somefun said. “We shouldn’t do just one of these things“We should do them all.”
In fact, exercising before work and then sitting for eight hours or more can negate some of the benefits of exercise for the brain, said Amal Wanigatunga, associate professor of Epidemiology at the Johns Hopkins Bloomberg School of Public Health, who was not involved in the research.
Exercise increases blood flow and oxygen to the brain
Breaking up long periods of sitting by standing or walking can improve cerebral blood flow, Wanigatunga said.
“The brain has very small capillaries, so if blood flow is reduced, especially in these very small pathways, that may be the basis of brain atrophy,” he explained.
Muscle contractions – which occur when the body moves – release a protein called brain-derived neurotrophic factor, or BDNF. This molecule enhances cognitive function, generates new neurons and improves the connections between them, especially in the hippocampus, the part of the brain that converts short-term memory into long-term memory, Wanigatunga explained.
Similarly, physical activity has been shown to reduce a peptide called beta-amyloid, which causes plaque buildup in the brain and may play a role in Alzheimer’s disease and dementia, Hwang said.
Exercise also reduces chronic inflammation in the brain, which hinders its ability to repair itself, Oye-Somefun said.
“Whatever the underlying cause of dementia, it appears that physical activity can have a beneficial impact on the brain,” Hwang said.
(This is recommended by experts to stop typhus cases in Los Angeles)
A recent study suggested that staying mentally active while sitting, such as solving a puzzle or knitting, could help keep the brain active even when leading a sedentary life.
While activities that stimulate the brain might make sitting for long periods of time less harmful than, say, watching TV, mental stimulation provides the brain with different protection than physical activity, so both are important, Oye-Somefun said.
Performing activities activates neural pathways in the brain, while exercise improves blood flow to the brain and causes muscles to contract, Hwang explained.
Both activities “contribute to brain health in their own way,” he said.
Sleeping too much or too little is linked to dementia
There are some science-backed hypotheses about sleep and dementia.
First, sleep allows the brain’s glymphatic system to remove waste, such as beta-amyloid, which accumulate during waking hourssimilar to how the lymphatic system removes waste from the rest of the body, Hwang explained. Spending adequate time in different phases of the sleep cycle, such as REM, can also help the brain consolidate memories.
The answer may also be much simpler: A good night’s sleep makes it easier to manage stress, eat right and get enough exercise, he said.
“If you get a good night’s sleep, you have the means, the clarity and the willpower to think about everything else, your activity and your diet,” said Wanigatunga of Johns Hopkins University. “You have to sleep no matter what, so try to improve that and then work on the rest of those habits.”
Finally, constant physical activity is more important than intense exercise.
“Once you’ve made it a habit, you can perfect it,” Wanigatunga said.
