Neurology>Dementia

Leisure-Time Physical Activity in Midlife May Portend Better Brain Health Later

-Lower odds of lacunar infarct, more intact white matter integrity seen with higher PA levels

by Zeena Nackerdien PhD, CME Writer, MedPage Today 2021-01-22

Leisure-Time Physical Activity in Midlife May Portend Better Brain Health Later | MedPage Today

Must be read prior to engaging in activity

Study Authors: Priya Palta, A. Richey Sharrett, et al.; Nicole L. Spartano, Leonardo Pantoni

Target Audience and Goal Statement: Neurologists

The goal of this study was to determine if higher levels of leisure-time moderate-to-vigorous intensity physical activity in midlife or late life were associated with lower brain pathology burden in late life.

Question Addressed:

  • Were higher levels of leisure-time moderate-to-vigorous intensity physical activity in midlife and late life associated with larger gray matter volumes, less white matter disease, and fewer cerebrovascular lesions measured in late life?

Study Synopsis and Perspective:

There has been inconsistent evidence on the effects of physical activity on brain measures or cognitive improvement, with some studies finding benefits and some not.

Action Points

  • Higher levels of leisure-time moderate-to-vigorous intensity physical activity in midlife were associated with lower odds of lacunar infarct in late life and more intact white matter integrity compared with no physical activity in midlife, according to a prospective study.
  • Realize that the type of exercise prescribed in an intervention might also play a role, with physical activity interventions that have an enriching element possibly having the most success.

Most studies on assigned physical activity provided only snapshots of a specific time period and were not reflective of physical activity over the course of a lifetime. For example, associations of physical activity and subclinical brain markers observed at older ages may be subject to reverse causality due to comorbidities, age-related changes in lifestyle, or initial cognitive impairment.

Therefore, there was an unmet need for observational studies with repeat physical activity measures to determine the long-term role of physical activity on brain structure.

According to a recent prospective study, higher levels of leisure-time moderate-to-vigorous intensity physical activity in midlife were associated with less late-life brain damage on MRI.

Compared with no physical activity in midlife, high levels were associated with lower odds of lacunar infarct in late life (OR 0.68, 95% CI 0.46-0.99) and more intact white matter integrity, reported Priya Palta, PhD, of Columbia University Irving Medical Center in New York City, and colleagues in Neurology.

“Our study suggests that getting at least an hour and 15 minutes of moderate-to-vigorous intensity physical activity a week or more during midlife may be important throughout your lifetime for promoting brain health and preserving the actual structure of your brain,” Palta said in a statement. “In particular, engaging in more than 2 and a half hours of physical activity per week in middle age was associated with fewer signs of brain disease.”

The researchers used longitudinal data from the Atherosclerosis Risk in Communities (ARIC) cohort. The study involved 1,604 participants with a mean age of 54 at baseline; 55% were women and 27% were Black.

The participants underwent five physical examinations over the course of 25 years. At baseline (1987-1989) and 25 years later, participants answered questions about their moderate-to-vigorous physical activity in the past year, which was classified as none, low, middle, or high at each time point. Activity was assessed with the modified Baecke questionnaire.

Mean age of participants at the time of MRI was 76.2 years. Scans were conducted to evaluate gray and white brain matter and areas of disease or injury in the brain.

At midlife, 34% of participants reported no moderate-to-vigorous intensity physical activity, 11% had low levels (1 to 74 minutes a week), 16% had middle levels (75 to 149 minutes a week), and 39% had high levels (150 minutes a week or more).

Following adjustments for demographics and lifestyle factors, people with no self-reported moderate-to-vigorous intensity physical activity had an average 47% greater odds of developing brain lesions 25 years later compared with people with high levels of physical activity.

High moderate-to-vigorous midlife activity was associated with better white matter integrity (mean fractional anisotropy difference 0.13 per SD, 95% CI 0.004-0.26; average mean diffusion difference -0.11 per SD, 95% CI -0.21 to -0.004) in late life, compared with no moderate-to-vigorous midlife activity. High moderate-to-vigorous activity was not associated with gray matter volume.

While odds of lacunar infarcts were lower with more intense midlife activity, odds of cortical infarcts or subcortical microhemorrhage were not.

When findings were adjusted for vascular risk factors, including hypertension, diabetes, BMI, and stroke, the relationship of midlife physical activity to lacunar infarcts was attenuated, but not the relationship to white matter microstructure.

Late-life moderate-to-vigorous physical activity also was associated with most brain measures compared with no moderate-to-vigorous activity, but because this was a prospective study that spanned decades, the “association between midlife physical activity levels and later-life brain imaging features makes a much stronger case for causality than does the same relationship when measured only in late life,” the researchers noted.

The study had several limitations. It relied on self-reported data and did not include physical activity besides leisure-time activity, such as work-related activity. Attrition over the study period may have resulted in healthier participants attending the last examination.

Source References: Neurology 2021; DOI: 10.1212/WNL.0000000000011375

Editorial: Neurology 2021; DOI: 10.1212/WNL.0000000000011376

Study Highlights and Explanation of Findings:

This prospective study found that higher levels of leisure-time physical activity in midlife were associated with less late-life brain damage on MRI.

“Our results show that staying active during midlife may have real brain benefits,” Palta said in a statement. “In particular, consistently high levels of midlife moderate-to-vigorous intensity physical activity were associated with fewer brain lesions in later life.”

Other research has shown that brain lesions may be caused by inflammation or other damage to the small blood vessels in the brain. “Our research suggests that physical activity may impact cognition in part through its effects on small vessels in the brain. This study adds to the body of evidence showing that exercise with moderate-to-vigorous intensity is important for maintaining thinking skills throughout your lifetime,” she added.

The “most consistent evidence for the protective effect of physical activity against dementia risk has been reported to be leisure time physical activity, and it is unclear whether there is benefit to other types of physical activity that may be less ‘enriching,'” observed Nicole Spartano, PhD, of Boston University School of Medicine, and Leonardo Pantoni, MD, PhD, of University of Milan in Italy, in an accompanying editorial.

Regarding the association between higher levels of midlife physical activity with fewer lacunar infarcts, the editorialists said that when adjustments were made for vascular risk factors, this relationship was attenuated, but not the relationship to white matter microstructure. This implies that “evidence from this study supports a hypothesis that the mechanisms linking physical activity and the brain are likely multi-dimensional, including mechanisms other than simply improving cerebrovascular health,” they wrote.

Spartano and Pantoni also noted that many physical activity interventions have been conducted in populations with a somewhat higher risk of cognitive decline or those who already have mild cognitive impairment or dementia, questioning whether these individuals are the optimal target population for studying the benefits of physical activity on the brain.

Additionally, if the benefit of physical activity is in improving cognitive reserve or resilience of the brain, interventions in those who already have enriching, socially privileged environments might not be as effective.

They proposed that physical activity interventions set at important periods in an older person’s life, when his or her environment changes in terms of cognitive or social enrichment, could potentially be even more successful. Such key time periods might include a change in health/disability, death/disability of a spouse, retirement, or even a divorce or other changes in the living environment.

The type of exercise prescribed in an intervention might also play a role. “It is possible that future work will uncover the requirement that physical activity interventions to reduce dementia risk actually have an enriching element, such as in leisure-time activities, rather than be strictly rote, mechanical movement,” they wrote.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco

Primary Source  –  Neurology

Source Reference: Palta P, et al “A prospective analysis of leisure-time physical activity in midlife and beyond and brain damage on MRI in older adults” Neurology 2021; DOI: 10.1212/WNL.0000000000011375.

Secondary Source  –  Neurology

Source Reference: Spartano NL, Pantoni L “What can longitudinal observational studies of physical activity teach us about prevention of dementia?” Neurology 2021; DOI: 10.1212/WNL.0000000000011376.

Additional Source  –  MedPage Today

Source Reference: George J “Midlife Physical Activity Correlates With Late-Life Brain Structure” 2021.