High Cardiovascular Fitness May Fend Off Dementia

You are quite likely to get dementia.

Your chances of getting dementia.

1. A documented 33% dementia chance post-stroke from an Australian study?   May 2012.
2. Then this study came out and seems to have a range from 17-66%. December 2013.
3. A 20% chance in this research.   July 2013.

What the fuck are your doctors' protocols such that you can exercise to such a fitness state?

High Cardiovascular Fitness May Fend Off Dementia

Very fit women had 90% lower dementia risk decades later

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• by Judy George, Contributing Writer, MedPage Today March 14, 2018

Action Points

• High cardiovascular fitness in midlife was associated with a markedly decreased risk of dementia decades later, but causality could not be determined, in a prospective study of Swedish women.
• Note that fitness is a measure of cardiovascular function, strongly determined by genetics, age, sex, and body size, and influenced by lifestyle behaviors such as physical activity, meaning a person may be very fit because of factors other than physical activity affecting fitness.

Highly fit women in midlife were nearly 90% less likely to have dementia decades later, a prospective study in Sweden found.

Over 44 years of follow-up, the adjusted hazard ratio for dementia was 0.12 for women with high cardiovascular fitness and 1.41 for low-fitness women, compared with women of medium fitness, reported Helena Horder, PhD, of the University of Gothenburg and colleagues.

And when highly fit women did develop dementia, it was 11 years later than for women who were moderately fit, the team wrote online in Neurology

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"The most exciting result is that so few in the group with highest fitness developed dementia -- namely two persons, or 5%," Horder told

While many observational studies have linked physical activity to preserved cognitive function, few have assessed cardiovascular fitness objectively, Horder and colleagues noted. Even fewer (the Cooper Center Longitudinal Study is one) have follow-up periods that span decades.

In this study, the researchers tracked a population-based sample of 1,462 women who were evaluated in 1968 when they were 38 to 60 years old. A subsample of 191 women participated in an exercise test and were followed until December 2012 for dementia diagnoses. Women in the exercise test did not differ from the total sample in age or cumulative dementia incidence (23.0% versus 22.1%, P=0.780).

These women had their cardiovascular fitness assessed through a stepwise-increased ergometer cycling test that was supervised by a physician. They exercised to exhaustion and had their heart rate, electrocardiogram data, blood pressure, respiratory frequency, and perceived exertion recorded.

Participants were 50 years old on average, and their mean peak workload was 103 watts. Of 191 women, 40 had high fitness (120 watts or higher), 92 had medium fitness, and 59 had low fitness (80 watts or less, or had the test stopped due to high blood pressure, chest pain, or other cardiovascular problems).

During 44 years of follow-up, 44 women developed dementia. The cumulative incidence of all-cause dementia was 32% for low, 25% for medium, and 5% for high cardiovascular fitness.

After adjusting for age, body height, triglycerides, smoking, hypertension, wine consumption, physical inactivity, and income, the researchers found that the hazard ratio for all-cause dementia was 0.12 (95% CI 0.03–0.54) among high-fitness women and 1.41 (95% CI 0.72–2.79) among low-fitness women, compared with women of medium fitness.

Dementia incidence was highest, at 45%, in women who needed to have the exercise test interrupted at sub-maximal workload. This could mean that adverse cardiovascular processes in midlife may increase dementia risk, the researchers suggested.

"An interesting mechanism that needs to be further investigated is the direct effects of physical activity and high fitness on brain structures, such as the hippocampus," said Hoarder. "Age-related changes in brain structures might be delayed through positive effects on small vessel circulation, inflammatory mechanisms, and growth factors."

To translate these findings from a clinical perspective, it's important to understand the term fitness, noted Nicole Spartano, PhD, of Boston University School of Medicine, and Tiia Ngandu, MD, PhD, of the National Institute for Health and Welfare in Helsinki, Finland, writing in an accompanying editorial.

"Fitness is a measure of cardiovascular function, which is strongly determined by genetics, age, sex, and body size, but also is influenced by lifestyle behaviors such as physical activity. In other words, a very fit person may not necessarily be a very active person, and vice versa, because of factors other than physical activity affecting fitness."

Cardiac output -- which can be increased in training, but has substantial heritability and varies greatly among sedentary individuals -- determines about 70% to 85% of fitness, Spartano and Ngandu noted. While it is likely the combination of cardiovascular function and physical activity drove the associations seen in this study, it is also possible that they are the result of genetic and other influences.

Study limitations, the researchers noted, included the small sample size, reducing the possibilities for subanalyses, and since the cohort was relatively homogeneous, the results may not apply to other populations. In addition, the 1968 exercise test measured work capacity, not maximal oxygen consumption with expired gas analysis, which is the gold standard for cardio-respiratory fitness, and the women's fitness level was measured only once, so changes in fitness over time were not captured.

The team added that because the study findings are not causal, future research should focus on whether improved fitness has positive effects on dementia risk and when high cardiovascular fitness is most important during the course of a life.

The study was supported by the Forte-Centre Aging and Health: Centre for Capability in Ageing (AGECAP).

Neither the authors nor the editorialists reported having any conflicts.

• Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College and Dorothy Caputo, MA, BSN, RN, Nurse Planner

• Primary Source

Neurology

Source Reference: Horder H, et al "Midlife cardiovascular fitness and dementia" Neurology 2018; DOI: 10.1212/WNL.0000000000005290.

Secondary Source

Neurology

Source Reference: Spartano N, Ngandu T "Fitness and dementia risk" Neurology 2018; DOI: 10.1212/WNL.0000000000005282.