Human brain is usually decreasing over the years, so its volume decreases by about 0.2 percent per year until 60 years of age.
More intense brain reduction is associated with cognitive problems, says the team of Nicholas Spartan from the Boston University Medical School.
Their new research, conducted on middle-aged individuals, revealed that every extra hour that is spent in a light physical activity is associated with a 0.22 percent increment of brain volume. If You spend 10 to 19 minutes per day in moderate physical activity, such as race walking, is associated with a 0.29 percent increment of the brain volume compared to less than 10 minutes of easy activity.
These levels of activity are less than what is recommended as a minimum needed to achieve significant health benefits. The recommendations usually state that adults should spend at least 150 minutes per week in moderately intensive physical activity (about 21 minutes per day) or 75 minutes per week of intensive exercise, and at least 10,000 steps a day.
According to a new study, people who have passed at least 7,500 steps a day have a higher brain volume than those who walked less than 7,500 steps a day.
Scientists estimate that every additional hour of light physical activity is associated with 1.1 years of less aging of the brain, although they warn that because of respondents youth, the assessments may not be entirely accurate.
They also noted that the links between the levels of activity, the number of steps and brain volume were not consistent, and small systemic benefits were observed only at the highest levels of effort.
For research purposes, scientists tested 2,354 middle-aged volunteers and measured their energy consumption and the number of steps. With the help of magnetic resonance, the volume of their brain is estimated in relation to the volume of the skull.
“There should not be much space in the skull that is not filled with brain tissue. If we see a lot of empty space, it suggests that the brain has decreased and it can be associated with dementia,” says Spartan.
The discovery that the lowest level of physical activity associated with a lower brain volume, even in middle age, suggests that some adults enter older years with a lower brain volume, which leads them to a more unfavorable position in terms of maintaining reduced brain tissue.
Professor of neuropsychology at the University of Columbia in New York, Jakov Stern, who was not involved in the study, suggests that the study only examined the relationship between physical activity and brain volume, and not cognitive functions and risks of dementia. It notes that further research is needed to clarify this.