Although it has a strong genetic component, can we change something in our daily lives to prevent or slow it down? The answer is yes. Being physically active has been shown to slow down and even correct the evolution of many brain alterations that occur in the disease and its cognitive and behavioral consequences.
Alzheimer’s disease affects 36 million people worldwide – it is estimated that a new case is diagnosed every seven seconds. Its prevalence doubles every five years after reaching the age of 60 . Memory loss and cognitive and behavioral alterations condition the dependence and quality of life of patients, ultimately causing death from indirect causes.
Pharmacological treatment is aimed at stopping the evolution of some of its symptoms, although, unfortunately, they do not reduce, much less substantially reverse, the cognitive alterations caused. For this reason, alternative therapies such as psychotherapy, cognitive therapy and physical exercise are currently being promoted, which have demonstrated their potential by attenuating its pathophysiology and, consequently, reducing symptoms.
More than 2,000 years ago, the Latin poet Juvenal already pointed out the relationship between physical health and mental health through his maxim “Mens sana in corpore sana” . Although he was right, at present we clarify that doing physical exercise on a regular basis – 150 minutes a week of moderate-intense intensity exercise according to the World Health Organization (WHO) – improves the structure and functioning of our brain through various biological mechanisms that we are increasingly understanding.
Benefits for the brain
A few decades ago it was thought that all benefits produced by physical exercise at the brain level were regulated by psychological phenomena – anxiolytic and antidepressant effects, euphoria, pleasure – and sociological – social interactions and environmental enrichment have shown benefits on the brain. Today we know that physical exercise organically and structurally modulates brain tissue through various biological mechanisms such as increasing the number of nerve cells (neurogenesis) in critical regions for this disease such as the hippocampus, increasing the density of their connections ( synaptic plasticity), improving cerebral blood flow, metabolism, reducing oxidative damage, as well as improving the degradation of toxic waste products such as β-amyloid protein or waste caused by the death of neurons.
The investigations that study the cerebral improvements produced by the exercise have been carried out mainly in animal models and, to a lesser extent, although worthy of mention given the obvious ethical and technical difficulties, in humans. In these studies it has been shown that for a muscular action to have consequences at the brain level, different signals must be activated, including hormones, neurotransmitters, antioxidant defenses and neurotrophic factors, such as Brain Derived Neurotrophic Factor (BDNF), that mediates the survival, repair and proliferation of neurons and whose deficit has been related to an increased risk of suffering from a neurodegenerative disease.
Lifestyle influences
We recently published a meta-analysis study in the Mayo Clinic Proceedings journal in which we analyzed the risk of Alzheimer’s disease based on physical activity carried out in previous years in 23,345 people between 70 and 80 years of age. In the study we showed that those people who had been physically active, according to the WHO recommendations, for approximately the previous 5 years, had a 40% lower chance of developing Alzheimer’s compared to sedentary people.
Today we know that many of the brain regions and functions affected in Alzheimer’s disease are susceptible to structural and functional improvement thanks to regular physical exercise. Although the risk of suffering from this dementia has a strong genetic component, Alzheimer’s can also be modulated by modifiable factors such as lifestyle. Currently, few, if any, interventions produce such pleiotropic effects (affecting multiple characteristics) and adjuvant (contributing in a complementary way to produce an effect, for example, of a drug) on the evolution of Alzheimer’s disease .
Helios Pareja and Alejandro Lucía are researchers at the European University. His research group is dedicated to understanding the biological mechanisms by which exercise helps prevent (and even treat) many diseases. This article has been written in collaboration with the Department of Communication of the European University.
