Exercise and the Hippocampus

Dr. Art Kramer presented his research on the cognitive effects of exercise on November 30th to a rapt audience, myself included. There are plenty of reasons to exercise: increased cardiovascular endurance, stress reduction, and overall body appearance and tone. But, it can be easy to fall off the exercise bandwagon sometimes. I try to workout a maximum of five days a week; sometimes I only make it to 2 or 3 days, and I sometimes I get too stressed with school and validate skipping the gym entirely. For me, it's easy to rationalize not exercising to strengthen my heart because I'm 21 and don't really need to think about that. School often takes precedence. However, what if exercising and working your body helped with school in the long run?

Dr. Kramer discussed how exercise can improve connectionism and aging, and how exercise can also improve cognitive functioning in children. High-fit children were less distracted by music when they were in the simulated street crossing and had way better decision making skills. These are very clear and apparent reasons to get up and exercise, even when you're stressed! The subject of exercise and the brain is actually what first spurred my fascination with neuroscience a few years ago. I remember reading a paper about how the old adage "The brain cells you're born with are the only ones you've got" was actually false, and how research was found neurogenesis and new cell production in the hippocampi of rats who ran regularly. This really got my attention, and is something that I am interested in researching with adults and depression. Most doctors recommend exercise for depressed patients, but this is definitely an area that could use more exploring in terms of the actual neurological affect of exercise on the brain and why it improves depressive patients functioning.

If exercise improves hippocampal volume and thus aging and emotional coping, everyone should really get the recommended amounts of exercise for their own sake. However, working out and being healthy can be confusing sometimes because there's so many options, and so many conflicting ideas for what kind of exercise is the most beneficial for each person. In a study by Kirk Erickson and colleagues (including Dr. Kramer as well!), the researchers attempted to elucidate exactly this. They compared individuals who either took place in an exercise condition with moderate-intensity aerobic exercise or in a toning and stretching condition. They found that the aerobic exercise increased hippocampal volume by 2% and increased associated BDNF levels (Brain derived neurotrophic factor, a nerve growth factor) (Erickson et al. 2010). Hippocampal shrinkage is associated in aging, so this has huge implications for aging and Alzheimer's prevention!

References:
Erickson, K. et al. (2010). Exercise training increases size of hippocampus and improves memory, PNAS, 108(7), 3017-3022.