You may have heard that exercising helps prevent a number of diseases, including Alzheimer’s. Sleeping well is also good for your health. But, after all, how can moving the body help the brain? And what does a good night’s sleep have to do with dementia?
All over the world, research is trying to explain how the acquisition of healthy habits prevents Alzheimer’s disease. These studies are all the more important in a context where there is still no treatment capable of reversing the disease, which affects 55 million people worldwide.
To first noticeable manifestations Alzheimer’s disease is memory loss: the brain has trouble forming new memories, and it’s common to forget everyday tasks like where you kept your keys or the apartment number where you live.
It is possible that the person who suffers from the dysfunctions does not realize that he has memory problems. At this time, family members usually notice that something is wrong and ask for help. The doctor then does clinical tests and even imaging tests to confirm Alzheimer’s disease.
For the patient’s family, it seems that the disease was diagnosed early, after all, soon after the first manifestations they asked for help. Not quite: it is likely that the biological mechanisms at the origin of the disease had already been at work for years.
“The onset of symptoms does not mean the onset of the disease,” explains Sergio Ferreira, professor at the Institutes of Biophysics and Medical Biochemistry at the Federal University of Rio de Janeiro (UFRJ). “The alterations in the brain of the Alzheimer patient begin 20, 30 years before the first symptoms. There are phases of the disease with molecular changes, in the functioning of synapses, neurons and it accumulates. iceberg.”
In the not-too-distant future, scientists believe that a person in their 40s may begin to monitor, through tests, signs in the brain that indicate a risk of having Alzheimer’s disease. But if today there is no medicine that cures the disease, what is the advantage of having this diagnosis? For scientists, it is increasingly clear that, until treatments are discovered, we must focus on prevention.
A report published by a committee of scientists in the journal The Lancet, two years ago, showed that 12 factors, such as physical inactivity, hypertension and alcohol abuse, are linked to about 40% of cases of dementia, including Alzheimer’s disease. Eliminating negative habits does not guarantee that a person will never get Alzheimer’s disease, but it lowers the risk and can help delay the disease. And it’s good for both public health and individuals.
“What is understood today is that in any age group it is valid to adopt measures that reduce the risks. If I have never done physical activity and I’m 65, it’s worth starting regular physical activity as a strategy to improve health, mental health and reduce risk (dementia)“, explains Paulo Caramelli, professor at the Federal University of Minas Gerais (UFMG) and member of the advisory board of the International Society for the Advancement of Research and Treatment of Alzheimer’s Disease.
He is coordinating one part of a multicenter study that aims to show how drug-free interventions can lead to cognitive improvement in older adults. A similar survey in Finland, among people aged 60 to 77, showed, in just two years, that the group of older people who participated in physical activities, brain “training” and cardiovascular monitoring had a cognitive improvement.
From mood to hormone: how physical activity affects the brain
Aerobic physical activities such as running, swimming, cycling and dancing help control diabetes and high blood pressure – two risk factors for Alzheimer’s disease. In addition, they improve mood and, consequently, depression. Today, we already know that depression is also linked to Alzheimer’s disease (it can be a risk factor or a manifestation that precedes the appearance of the first clear signs of dementia).
Long-term research that has followed volunteers for years suggests that moderate to vigorous physical activity (not just walking around the mall; you have to sweat) is associated with a reduced risk of dementia.
And that’s not all: there also seems to be an effect of physical activity directly on the brain. One of the most important research on this subject was carried out in 2019 by scientists linked to the Federal University of Rio de Janeiro (UFRJ). They found that physical exercise promotes release of a protective hormone in the brain: irisin.
Research has shown that irisin is reduced in the brains of patients with Alzheimer’s disease and that by giving irisin to mouse models with the problem it is possible to restore the animals’ memory. “Our bet is that irisin strengthens synapses,” says Ferreira.
Keeping Your Blood Pressure Under Control: Fewer Strokes and More Oxygen
The report published in the magazine The Lancet recommended that middle-aged people in their 40s keep their systolic blood pressure below 130 mm Hg to reduce the risk of dementia, including Alzheimer’s disease. For reference, the ideal systolic pressure is 120 mm Hg and diastolic pressure is 80 mm Hg (usually translated as 12 by 8).
The studies published so far establish a clear link between hypertension and increased brain problems. One, with 8,600 participants in the UK, showed that a systolic blood pressure of 130 mm Hg or more in people aged 50 was associated with an increased risk of dementia.
“Those with a more serious cardiovascular condition, for example hypertensive patients, are at higher risk of cerebrovascular lesions, strokes or small ischemic or hemorrhagic lesions,” explains Caramelli. Such damage directly affects brain cells.
In addition, explains the professor, people with hypertension have a change in the system of passage of substances from blood vessels to brain cells. “If it corrects hypertension, it decreases this dysfunction of the blood-brain barrier and improves brain function.”
Finally, those who do not treat high blood pressure are at risk of heart failure – problems with the functioning of the heart muscle reduce, for example, the amount of blood that reaches the brain. The organ is deprived of adequate irrigation and oxygenation.
Sleep time is associated with “cleaning” the brain
How sleep is linked to dementia and, more specifically, Alzheimer’s disease is still being studied. It is clear, however, that cardiovascular health generally benefits from quality sleep. For most people, 7-8 hours a night is enough.
Studies have also shown that sleep disturbances are associated with the deposition of beta-amyloid protein in the brain and an increase in tau protein (two substances considered to be markers of Alzheimer’s disease). Also, while we sleep, brain activities responsible for fixing memories occur.
Another aspect that has been studied is the role of glial cells, a lesser known cellular system that supports neurons. They work like “dustbins” for the brain, sweeping up toxic substances – and they work best at night, which is all the more reason for take care of sleep.