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Researchers in Sweden gave middle age women initial exercise tests and followed them for 44 years. While both groups of women lived to that ripe age, those who could still use an exercise bike at a rate of six minutes in the initial test had a much lower risk of dementia later than those who did not complete the workout.
The results of the study, published on Wednesday in the Neurology journal, did not prove that exercise prevented dementia. However, it showed dramatic results of the correlation between exercise and a decreased dementia risk, USA Today reported.
Among the women, who were then between 38 and 60, who were able to bike the hardest over six minutes, 5 percent of them still developed dementia. The rate was 25 percent for those with medium fitness and 45 percent for those not fit. Those who were moderately fit decreased their dementia risk by 88 percent.
Of the 5 percent that developed dementia, their average age was 90, while for the moderately fit women, it was 79 years old.
Ingmar Skoog, a psychiatry professor at The University of Gothenburg in Sweden, said he was surprised that the finding was so strong. He added it just showed the importance of exercise. However, because only 191 women underwent the initial fitness test, it is hard to maintain statistical significance while dividing the group into sub-categories of more or less fit women. The author acknowledged that because all the participants in the study were Swedish women, it limited the ability to generalize its conclusions to a more diverse population.
He said that because Alzheimer’s disease and other forms of dementia are believed to start 15 to 20 years before the symptoms show, it would make sense to exercise in mid-life to affect the risk. But he said exercise alone is not sufficient to prevent Alzheimer’s.
Skoog pointed out that avoiding smoking, having enough exercise and sleep, eating a healthy diet, and similar activities also prevent cardiovascular diseases. David Knopman, a fellow of the American Academy of Neurology, said it makes sense to maintain a healthy lifestyle in mid-life, years before the ailment sets in.
He said that starting late in life is better than not starting at all. However, beginning in mid-life seems to confer a larger benefit. Knopman, the associate director of the Alzheimer’s Disease Research Center at Mayo Clinic in Rochester, Minnesota, said that while it is not entirely clear why exercise helps prevent or put off Alzheimer’s, it is likely because exercise maintains good blood flow to the brain. He explained that when the brain is healthier from a vascular point of view, it can absorb more Alzheimer’s pathology before people become symptomatic.
What type of exercise is best to lower risk?
Keith Fargo, the director of scientific program and outreach at the Alzheimer’s Association, a nonprofit, said the type of study done cannot exactly identify what kind of exercise is best or how much is needed. He said that only a study with a placebo group and monitors people going forward can do that.
He said it does not mean that mid-lifers must run in triathlons, but Fargo said that more than a 10-minute dog walk would be a good idea.
Helena Horder, a researcher at the Center for Aging and Health at the University of Gothenburg, said the findings suggested that high cardiovascular fitness is associated with a decreased risk of dementia. It is also another way of saying that good heart health is linked with good brain health, Live Science reported.
There are several lifestyle studies that will soon get underway. One of it, the US POINTER study, is backed up by the Alzheimer’s Association. It will offer adults considered at risk, those between the ages 60 and 79, a series of lifestyle interventions to see if they can impact Alzheimer’s risk. These studies are always seeking volunteers, Fargo said.
These studies should allow researchers to provide clearer recommendations for exercise and other lifestyle modifications in the next three to five years. The lifestyle changes include sleep, diet, and social activities.
Laura Baker, from the Wake Forest School of Medicine in North Carolina who is conducting her own research into fitness and dementia, said it is not about super fitness but a very average ability to ride a bike for a few minutes. She described it as hearing yourself breathing and starting to sweat, while the heart rate begins to go up, NBC News reported.
According to an editorial that accompanied the study, it suggested additional research to determine if the link between fitness and dementia is solely because of the influence of heart health on brain health, or if physical activity influences the brain independently of the activity’s cardiovascular effects.
In the US, there are more than 5 million Americans with Alzheimer’s, and their number is expected to increase in the coming years.