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Physical Fitness Level May Predict Your Risk For Dementia

You might dread the idea of exercise, but if you knew that it could lower your risk of developing dementia, would you be more motivated for a workout?

According to the Alzheimer’s Association, 1 in 5 women will develop Alzheimer’s disease by age 65 and the lifetime risk of any form of dementia in women is approximately 35%.  Sobering statistics.   Despite astronomical rates of dementia, prevention and treatment strategies are slow to follow. 

Well, I don’t know about you, but I’d like to beat it. If there’s something that can be done, I'm game.  I’m going to summarize a study for you that blew me away.

In 2018, a team out of Sweden published results of a groundbreaking study that evaluated the cardiovascular fitness levels of 119 Swedish women ages 38-60, and their risk of developing dementia over a 44 year follow up period. Women were asked to use an exercise bike with increasing tension until they hit exhaustion. 

Here is a brief summary of the results: 

Physical fitness level was rated high, medium and low based on the peak workload of the individual during the period of exercise.  The team measured a person's workload in terms of watts, which is a unit of power measuring the amount of work over a period of time. 

High fitness level: >120 watts 

Medium fitness level: 81-119 watts

Low fitness level: <80 watts

If you want to know what these wattage outputs feel like, try out a machine at the gym that measures watts.  Often you will see watts on stationary bikes, such as Peloton.  

The results of this research was astounding.  

Over the 44 year follow up, dementia occurred in: 

32% of women in the low fitness category

25% of women in the moderate fitness category

And ONLY 5% of women in the high fitness category

When compared with Medium fitness levels, high fitness levels decreased the risk of dementia by 88%.  HELLO!

And, not to scare people, but folks that were unable to complete the assessment due to early fatigue, blood pressure or heart rate abnormalities, ECG changes or chest pain, 45% developed dementia.   

Another interesting finding was that when weight was factored into the analysis, the association was less, meaning weight was not as predictive of dementia risk compared with fitness level.   The authors note that this suggests we should focus our attention to overall fitness rather than weight loss.

The study was able to apply statistical analyses to limit the impacts of confounding factors on the outcomes.  They factored in age, weight, smoking history, education, income levels, activity level day to day, alcohol use, blood pressure, cholesterol, and history of heart problems or stroke. 

Study limitations included the narrow and small study population (Swedish, 119 subjects).  Additionally, fitness was measured at only 1 time point, leaving us to speculate on the value of physical fitness maintenance over time.  

Well, in any case, bring it on.  I’m ready to hit the track, the pool, the courts, the bike, all of it.

If you’re looking for ways to build up your fitness and just can't gather the activation energy, look out for my upcoming post on enjoying exercise by thinking outside of the box. 

On the horizon:

In the Spring of 2023, the National Institute of Aging announced allocation of a $4.5 million grant to fund a study examining the effects of physical fitness training in people with memory changes over the age of 65.  Can we delay or reverse the onset of dementia? Stay tuned.

Julie Brownley, MD PhD

Helena Hörder, Lena Johansson, XinXin Guo, Gunnar Grimby, Silke Kern, Svante Östling, Ingmar Skoog. Midlife cardiovascular fitness and dementia. Neurology, 2018; 10.1212/WNL.0000000000005290

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