Women with a high level of physical fitness at middle age were 88 percent less likely to develop dementia later in life when compared with women whose fitness level was labeled moderate according to a new study published in the online journal Neurology.

And the highly fit women who did develop dementia did so an average of 11 years later than those in the moderate fitness category.

Researchers at the University of Gothenburg in Sweden used an exercise test to measure the cardiovascular fitness of 191 women with an average age of 50. They pedaled a bicycle until they were exhausted and were then divided into three categories based on the results.

A total of 40 women met the criteria for being highly fit, which was a peak workload of 120 watts or higher. Ninety-two qualified for medium fitness and 59 women had a peak workload of 80 watts or less or had to have their test stopped because of physical complications such as chest pain. They made up the low fitness category.

These same women were then tested for dementia six times a year for the next 44 years. A total of 44 women developed dementia with the most coming in the low and moderate fitness categories. Only five percent of the highly fit women developed dementia compared to 25 percent of those in the moderate category and 32 percent in the low category. Of the ones who could not complete the test, 45 percent developed dementia.

The study was limited by the fact only 191 women were involved and the fitness level of the participants was only measured at the outset, but researchers are encouraged by what they learned.

"These findings are exciting because it's possible that improving people's cardiovascular fitness in middle age could delay or even prevent them from developing dementia," said study author Helena Hörder, Ph.D. "However, this study does not show cause and effect between cardiovascular fitness and dementia, it only shows an association.

“This indicates that negative cardiovascular processes may be happening in midlife that could increase the risk of dementia much later in life," Hörder said. “More research is needed to see if improved fitness could have a positive effect on the risk of dementia and also to look at when during a lifetime a high fitness level is most important.”

Click here to read more from the American Academy of Neurology