Walking is associated with slower cognitive decline and greater preservation of brain volume in older adults with mild cognitive impairment or Alzheimer’s disease as well as in cognitively healthy older adults, a longitudinal study has shown.
Patients with mild cognitive impairment (MCI) or Alzheimer’s disease (AD) who walked just five miles/week had significantly less neurodegeneration on three-dimensional volumetric MRI and a more than 50 percent reduction in cognitive decline and memory loss over 10 years than did sedentary cognitively impaired individuals, according to the University of Pittsburg.
Physical activity may be a way to reduce risk (for AD) by strengthening brain structure. He and his colleagues analyzed the responses of 1,479 participants to questionnaires in the 20-year, ongoing Cardiovascular Health Study-Cognition Study (CHS-CS). In 1989-1990, these subjects completed standardized, self-reported questionnaires of physical activity . Of these subjects, 927 underwent brain MRI in 1992-1994. In 1998-1999, 426 subjects underwent high-resolution, three-dimensional volumetric brain MRI.
The 426 subjects were divided into those who were cognitively normal at the time of volumetric MRI (n=299;mean age 78 years) and whose who were impaired (n=127; mean age, 81 years) with either MCI (n=83) or AD (n=44).
Among patients with AD or MCI, walking five miles/week preserved brain volume and reduced memory loss overtime as patients were developing the disease. The reduction in memory loss that was associated with walking remained stable even after researchers controlled for a number of factors.
Normally aging patients who did not have MCI or AD at the time of volumetric MRI and who walked regularly also showed a significant reduction in brain atrophy over 10 years, compared with their more sedentary counterparts, as well as a 50 percent reduction in the risk of developing AD over total of 13 years.
However, the most exciting finding was the positive effects of physical activity in people who already had AD or MCI at the time of volumetric MRI. The brain images of these patients revealed preservation of brain volume in the exact same region that benefit people with healthy aging, specifically the prefrontal and temporal cortices. Furthermore, the amount and magnitude of these effects were even larger than in the normally aging group.
Among cognitively impaired subjects, MMSE scores declined on average by 1 point over 10 years in person who walked five miles/week, compared with five points in sedentary individuals. This statistically significant difference in the magnitude of memory loss was directly correlated with preserved hippocampal volume.