Poor physical fitness in middle age may be linked to a smaller brain size 20 years later, according to a study published in the February 10, 2016, online issue of Neurology.
“We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging,” said study author Nicole Spartano, PhD, with Boston University School of Medicine in Boston.
For the study, 1,583 people enrolled in the Framingham Heart Study, with an average age of 40 and without dementia or heart disease, took a treadmill test. They took another one two decades later, along with MRI brain scans. The researchers also analyzed the results when they excluded participants who developed heart disease or started taking beta blockers to control blood pressure or heart problems; this group had 1,094 people.
The participants had an average estimated exercise capacity of 39 mL/kg/min, which is also known as peak VO2, or the maximum amount of oxygen the body is capable of using in one minute. Exercise capacity was estimated using the length of time participants were able to exercise on the treadmill before their heart rate reached a certain level. For every eight units lower a person performed on the treadmill test, their brain volume two decades later was smaller, equivalent to two years of accelerated brain aging. When the people with heart disease or those taking beta blockers were excluded, every eight units of lower physical performance was associated with reductions of brain volume equal to one year of accelerated brain aging.
The study also showed that people whose blood pressure and heart rate went up at a higher rate during exercise also were more likely to have smaller brain volumes two decades later. Spartano said that people with poor physical fitness often have higher blood pressure and heart rate responses to low levels of exercise compared to people with better fitness.
Spartano noted that the study is observational. It does not prove that poor physical fitness causes a loss of brain volume; it shows the association.
“While not yet studied on a large scale, these results suggest that fitness in middle age may be particularly important for the many millions of people around the world who already have evidence of heart disease,” she said.
About this neuroscience research
Funding: The study was supported by the National Heart, Lung and Blood Institute, the National Institutes of Health and the American Heart Association.
Source: Michelle Uher – AAN Image Source: The image is credited to Banalities and is licensed CC BY 2.0. Original Research:Abstract for “Midlife exercise blood pressure, heart rate, and fitness relate to brain volume 2 decades later” by Nicole L. Spartano, Jayandra J. Himali, Alexa S. Beiser, Gregory D. Lewis, Charles DeCarli, Ramachandran S. Vasan, and Sudha Seshadri in Neurology. Published online February 10 2016 doi:10.1212/WNL.0000000000002415 1526-632X
Midlife exercise blood pressure, heart rate, and fitness relate to brain volume 2 decades later
Objective: To determine whether poor cardiovascular (CV) fitness and exaggerated exercise blood pressure (BP) and heart rate (HR) were associated with worse brain morphology in later life. Methods: Framingham Offspring participants (n = 1,094, 53.9% female) free from dementia and CV disease (CVD) underwent an exercise treadmill test at a mean age of 40 ± 9 years. A second treadmill test and MRI scans of the brain were administered 2 decades later at mean age of 58 ± 8 years.
Results: Poor CV fitness and greater diastolic BP and HR response to exercise at baseline were associated with a smaller total cerebral brain volume (TCBV) almost 2 decades later (all p < 0.05) in multivariable adjusted models; the effect of 1 SD lower fitness was equivalent to approximately 1 additional year of brain aging in individuals free of CVD. In participants with prehypertension or hypertension at baseline, exercise systolic BP was also associated with smaller TCBV (p < 0.05).
Conclusion: Our results suggest that lower CV fitness and exaggerated exercise BP and HR responses in middle-aged adults are associated with smaller brain volume nearly 2 decades later. Promotion of midlife CV fitness may be an important step towards ensuring healthy brain aging.
“Midlife exercise blood pressure, heart rate, and fitness relate to brain volume 2 decades later” by Nicole L. Spartano, Jayandra J. Himali, Alexa S. Beiser, Gregory D. Lewis, Charles DeCarli, Ramachandran S. Vasan, and Sudha Seshadri in Neurology. Published online February 10 2016 doi:10.1212/WNL.0000000000002415 1526-632X