Progression of Alzheimer's disease slowed by exercise, research shows

In the latest research showing the benefits of staying active as you get older, exercise has been found to reduce the risk of Alzheimer's disease. A new study show it's still beneficial even when harmful deposits are already present in the brain. Washington (dpa) – Even a few thousand steps a day can slow the progression of Alzheimer’s disease, according to new research published in the medical journal Nature Medicine. The analysis is the first to show effects in people who already have Alzheimer-typical changes in the brain, said Emrah Düzel, who heads an institute for cognitive neurology in Germany and was not involved in the study. "Here, physical activity appears to slow the spread of these changes over years and, in connection with that, to protect mental performance." Alzheimer's disease is the most common form of dementia and is believed to contribute to 60–70% of the world's 57 million cases of dementia, according to World Health Organization figures. The causes of the disease, in which nerve cells gradually die, are not yet fully understood. Known risk factors include diabetes, sleep disorders and depression. Among physically active people with preclinical – and still asymptomatic – Alzheimer’s, the researchers recorded less cognitive decline than among those who were physically inactive. According to the study, as few as 3,000 steps a day can help slow the build-up of harmful tau protein clusters in the brain. An even greater effect was seen at 5,000 to 7,500 steps, reported the team led by Wai-Ying Wendy Yau of Mass General Brigham in Boston in Nature Medicine. The results confirm that a lack of exercise is a risk factor for Alzheimer’s, Düzel commented. He added that, in general, physically active older people can preserve their brain substance better than those who are inactive. The study does not allow conclusions about the precise mechanism. One possible effect is that regular walking trains cognition. "The people have to navigate, orient themselves and interact with their surroundings." Cardiovascular health is also trained. In addition, increased physical activity releases a number of blood-borne growth and protective factors that can have a positive effect on the brain and could slow the spread of tau. For the study, the cognitive abilities of around 300 older adults were assessed, as was the presence of beta-amyloid plaques and tau in the brain at the start and then several times thereafter. Eighty-eight participants initially had preclinical Alzheimer’s. They had no symptoms, but an elevated burden of beta-amyloid plaques. The number of steps taken each day was measured at the outset, but long-term physical activity was not recorded. The data showed that tau, a marker of disease progression, accumulated more slowly in the brains of physically active people, which explains the cognitive decline being delayed by several years in some cases. People in the early phase of Alzheimer’s can therefore significantly slow disease progression by moving a lot on a regular basis. "Every step counts," Yau said, noting that even small increases in daily activity can add up over time to lasting changes in habits and health. One limitation of the study is that step counts were recorded only once at the beginning, said Düzel. "We know little about how much the participants moved in the years that followed." The researchers’ inference that there is barely any further improvement above 5,000 to 7,000 steps should be interpreted with caution. "I would by no means conclude that more exercise is not necessary." Intensive physical activity such as jogging or dancing can very likely trigger additional effects, he said. Additional factors were probably relevant as well. For example, Düzel explained that, beyond physical activity, a higher step count may also reflect a more cognitively active lifestyle. "Walking requires planning, orientation, memory and a range of other cognitive factors." The physician advises taking the results to heart and walking at least 5,000 to 7,000 steps a day. Walks should ideally be combined with exploring the surroundings, and preferably new surroundings. Sports such as cycling, dancing and jogging could, because of their intensity and the stimulation of the brain, have additional effects, Düzel said. "It's important that physical activity takes place regularly and is individually appropriate – in a form that is enjoyable and easy to integrate into everyday life," added René Thyrian from the German Centre for Neurodegenerative Diseases (DZNE). It should also be borne in mind that exercise is an important, but not the only, building block for promoting brain health; protective effects also come from lifestyle factors such as mental activity, social activity, low alcohol consumption and a healthy diet. The following information is not intended for publication dpa kll yyzz n1 cst coh

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