Dementia is not a specific disease. Rather it is a general term for a range of neurodegenerative diseases characterized by progressive memory loss and other cognitive impairments. It affects approximately 50 million people worldwide, according to the World Health Organization (WHO).

Dementia is most common among older adults, and a recent report suggests that more women live with Alzheimer's disease — a form of dementia — than men.

Many risk factors for dementia are related to lifestyle including high blood pressure, type 2 diabetes, smoking and depression, which means that by changing certain habits and leading a more healthful life, a person's risk of dementia can be decreased.

A new study from the University of Gothenburg in Sweden has now found that women who are very physically fit in middle age have an almost 90% decreased risk of being diagnosed with dementia later in life, unlike their moderately fit peers. 

Fitness Cuts Risk By 88%

For the purpose of the study, the researchers worked with 191 women, aged 50, on average. The participants' cardiovascular fitness (their ability to sustain physical effort over a prolonged period) was assessed through a bicycle exercise test.

The researchers asked the women to participate in the exercise until they felt physically exhausted; this allowed the researchers to establish what each participant's peak cardiovascular capacity was.

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The participants were then followed-up over a period of 44 years, during which time they were assessed for dementia six times. During that time, 44 of the participants developed the condition.

Of the women who scored as highly fit, only 5% were diagnosed with dementia in that 44-year interval. In contrast, 25% of the moderately fit participants and 32% of the women with low physical fitness levels developed the disease.

In other words, the women who were highly fit in middle age had an 88% lower risk of dementia than their moderately fit counterparts.

Also, the highly fit women who ended up receiving a dementia diagnosis did so at a much later stage in their lives — 11 years later, on average, than moderately fit women.

Another notable finding is that among the women who had been forced to cease exercise participation due to cardiovascular problems, 45% went on to develop dementia. This indicates that negative cardiovascular processes may be happening in midlife that could increase the risk of dementia much later in life.