Better Brain Health: A Priority for Women

New research shows women with high fitness were 88% less likely to have dementia

Posted May 13, 2018

 Zinkevych/Big Stock Photo
Source: Zinkevych/Big Stock Photo

For years researchers have sought to understand why American women have twice the rate of Alzheimer’s as men. Given that Alzheimer’s increases with age, initial theories presumed that because women live on average 5 years longer than men, they were simply more likely to be diagnosed. However, studies equating the age of Alzheimer’s diagnosis between men and women suggest that the answer is more complicated, and that women may have potentially greater biological vulnerability to developing the disease, possibly related to genetic, hormonal, or other factors.

One such study showed that “genetically vulnerable” men and women between ages 55 to 85 had similar odds of developing Alzheimer’s, except from ages 65-75, when the comparative risk jumped significantly for women, suggesting a potential interplay between genetic and post-menopausal/hormonal factors. Another study showed that women with mild cognitive impairment—a potential early form of Alzheimer's—declined at faster rates than men.

Other research suggests that because men with poor heart health are more likely to die in middle age, those men who live beyond 65 likely have healthier cardiovascular functioning (and possibly healthier brain functioning), which may contribute to lower rates of dementia as compared to women.

Given that brain health involves multiple factors, including exercise, diet, sleep, and “cognitive reserve,” it is not surprising that different studies have shown different variables to be important. However, a new study on women and dementia has provided unique information on a factor associated with an astonishing 88% reduced risk of dementia: high mid-life cardiovascular endurance.

In the study, 191 Swedish women ages 38-60 performed a cycling test, and were classified into three groups based on their peak level of cardiovascular capacity prior to reaching a state of exhaustion: low fitness (59 women), medium fitness (92 women), and high fitness (40 women). The study followed the women for up to 44 years. In that time, 44 women developed dementia: 32% in the low fitness group, 25% in the medium fitness group, and only 5% in the high fitness group. Further underscoring the relationship between fitness level and dementia, 45% of women who could not complete the fitness test developed dementia.

Overall, women in the high fitness group were 88% less likely to develop dementia than those in the medium fitness group. In addition, the two women in the high fitness group who developed dementia were diagnosed on average 11 years later than those women in the medium fitness group (at age 90 vs. age 79).

The study controlled for several factors that have been shown to influence brain health, including smoking, drinking, blood pressure, and cholesterol level. As with all correlational research, although we cannot interpret findings as proof that dementia is caused by differences in fitness level (given that results could relate to blood flow, genetics, diet, or a host of other differences between the groups), results are similar to other longitudinal studies that have found a dose-dependent relationship between fitness level and dementia, such that higher levels of fitness are associated with lower levels of dementia.

These findings, in combination with other research on the brain-boosting benefit of exercise, provide strong evidence that excellent fitness is foundational to brain health.

Here are 3 tips to get started on a fitness plan to boost your brain power:

1. Reframe fitness as “self care.” By consciously caring for your brain, you maximize your personal and professional success, enjoyment, and relationships. Take a few minutes to write down why brain health is important to you, and let those reasons motivate you to prioritize fitness as a vital aspect of your self care.

2. Start today, no matter your age or fitness level. Given that the brain changes associated with Alzheimer's begin about 20 years prior to diagnosis, it is ideal for women to prioritize brain health throughout their lives. However, it is important to note that some female “Super Agers” with excellent memory and brain health didn’t begin exercising until their 60’s or later, and that exercise enhances cognitive functioning even for individuals with moderate Alzheimer’s. In other words, it is never too late to begin!

3. Incorporate endurance and variety into your fitness routine. If you don’t exercise regularly, begin with 5 minutes of exercise per day. If you already exercise regularly, consider increasing the duration until you are getting 30 minutes of cardiovascular activity 4-5 times per week (an optimal level in multiple studies on brain health and fitness). Next, consider varying the intensity of your workout with techniques such as high-intensity interval training (HIIT), in which short bursts of high intensity cardiovascular exercise are alternated with low intensity activity or rest (HIIT has also been shown to reverse some aspects of overall cellular aging!). Also consider adding variety to your workout by doing different activities. For example, you might consider a mix of walking, hiking, swimming, dancing, HIIT, and biking (or lower intensity alternatives such as water walking, chair aerobics, stationary biking, or elliptical training). Be sure to check with your healthcare provider before making any changes to your exercise regimen.

Here’s to prioritizing the health of your beautiful brain for years to come!

References

Hörder, H et. al. (2018). Midlife cardiovascular fitness and dementia: A 44-year longitudinal population study in women. Neurology, https://doi.org/10.1212/WNL.0000000000005290 

Lin, K.A. et al. (2015). Marked gender differences in progression of mild cognitive impairment over 8 years. Alzheimer’s and Dementia: Translational Research and Clinical Interventions,1,103-115.

Neu, S.C., Pa, J., Kukull, W, et al. (2017). Apolipoprotein E Genotype and Sex Risk Factors for Alzheimer Disease. JAMA Neurology,74,1178-1189