As we age, our brains shrink in size due to loss of neural tissue. The term for this is ‘atrophy’, and it can be seen on MRI scans. Surprisingly, you don’t have to be old to have atrophy. In fact, the process of brain shrinkage probably begins in your 20s, and gets progressively more severe decade by decade.
Genetics and lifestyle factors primarily determine the rate at which your brain atrophies.
If you’ve been bummed out because your MRI shows significant atrophy, there is hope. To some extent, it can be reversed.
I was very excited to see a study published which indicated that exercise training increased brain volume. Specifically, this one study showed that moderate intensity aerobic exercise 3 days/week for year led to a 2% increase in hippocampal volume! This is very good news, since the hippocampus is felt to be the memory engine of the brain.
- moderate intensity exercise for this study was defined as: walking for 40 minutes per session. Participants wore heart rate monitors and were encouraged to walk in their target heart rate zone, which in this study was 60-75% of the maximum heart rate.
After a bit of digging around, I found another study which showed aerobic exercise training increased brain volume of gray and white matter in the prefrontal cortex. This region of the brain, separate from the hippocampus as discussed above, plays a very important role in concentration, judgement, problem solving ability, social behavior. [more information about the prefrontal cortex can be found here]
Proc Natl Acad Sci U S A. 2011 Feb 15;108(7):3017-22.
J Gerontol A Biol Sci Med Sci (2006) 61 (11): 1166-1170