There are activities that have been shown to be especially beneficial for people's health for various reasons: they improve balance and flexibility, strengthen bones, keep weight under control, protect joints, and even improve memory performance.
Now, an article published in 'Frontiers in Neuroscience' by Brazilian researchers affiliated with the Federal University of São Paulo (UNIFESP) and the University of São Paulo (USP) suggests that a widely known type of training can prevent Alzheimer's, or at least delay the onset of symptoms; which makes it a simple and affordable therapy for Alzheimer's patients.
Researchers have observed that including resistance exercises in the sports routine helps prevent or, at least, delay the onset of Alzheimer's. Although older people and people with dementia are unlikely to be able to do long daily runs or other high-intensity aerobic exercise, this activity has long been the focus of most scientific studies on Alzheimer's.
In order to observe the neuroprotective effects of this practice, researchers from the Departments of Physiology and Psychobiology of UNIFESP, and from the Department of Biochemistry of the Institute of Chemistry of USP (IQ-USP), carried out experiments with transgenic mice with a mutation responsible for the accumulation of beta-amyloid plaques in the brain. This protein accumulates in the central nervous system, impairing synaptic connections and damaging neurons, all characteristic of Alzheimer's.
During the study, financed by FAPESP, mice were trained to climb a 110-cm ladder with an 80° inclination and 2 cm between rungs. Tail loads corresponding to 75, 90 and 100 percent of their body weight were attached to them. The experiment mimicked certain types of resistance training performed by humans in gyms.
At the end of a four-week training period, blood samples were taken to measure plasma levels of corticosterone, the mouse hormone equivalent to human cortisol; increasing levels in response to stress increases the risk of developing Alzheimer's.
Hormone levels were normal (the same as those found in the control group made up of animals without the mutation) in the exercise-trained mice, and analysis of their brain tissue showed a decrease in the formation of beta-amyloid plaques.
"This confirms that physical activity can reverse the neuropathological changes that cause the clinical symptoms of the disease," says the first author of the article, Henrique Correia Campos.
"We also observed the behavior of the animals to assess their anxiety in the open field test -- which measures avoidance of the central area of a box, the most stressful area -- and found that resistance exercise reduced hyperlocality to levels similar to controls among mice with the Alzheimer's-associated phenotype", pointed out the co-first author of the article and researcher at the IQ-USP Neurosciences Laboratory, Deidiane Elisa Ribeiro. Agitation, restlessness, and wandering are common early symptoms of Alzheimer's and other types of dementia.
"Resistance exercise is increasingly proving to be an effective strategy to prevent the onset of sporadic Alzheimer's symptoms, not directly caused by a single inherited genetic mutation, which is multifactorial and may be associated with ageing, or to delay its progression." appearance in familial Alzheimer's. The main possible reason for this efficacy is the anti-inflammatory action of resistance exercise," says the last author of the article, Beatriz Monteiro Longo.
The animal model study was based on a review of the literature published in 'Frontiers in Neuroscience', where the same UNIFESP group compiled clinical evidence that the benefits of resistance exercise include positive effects on cognitive dysfunction, memory and behavioral problems in Alzheimer's patients, concluding that it may be an affordable alternative or coadjuvant therapy.
"Alzheimer's does not just affect the patient. It affects the whole family, especially in low-income households," says Caroline Vieira Azevedo, first author of the review article and a postgraduate student at UNIFESP. Therefore, she urges the use of both articles to stimulate the creation of public policies. "Imagine the cost savings if the onset of symptoms in older patients is postponed for ten years," she concluded.
Resistance exercises are one of four types of exercise, along with strength, balance, and flexibility exercises, that are most indicated. For endurance workouts, this may include brisk walking, running, dancing, bicycling, or climbing stairs at work or at home.
The World Health Organization (WHO) recommends resistance exercise as the best option to train balance, improve posture and prevent falls. In the end it is a training whose objective is to make the greatest effort for as long as possible. Aerobic and anaerobic resistance can be achieved.
Resistance exercise involves the contraction of specific muscles against external resistance and is considered an essential strategy for increasing muscle mass, strength, and bone density, as well as improving overall body composition, functional capacity, and balance. It also helps prevent or mitigate sarcopenia (muscular atrophy), making it easier to perform daily tasks.
