Exercise and Your Memory

Written by: Beth Levine

Aerobic exercise can not only help you lose weight in all the right places but also gain something in one very important place: your brain.  A region of your brain that is essential to memory has been shown in a recent study to increase in volume after getting regular cardiovascular exercise.

The research, which took place at the University of Illinois at Urbana-Champaign, demonstrated that when older people committed to a walking routine for a year, the hippocampus area of the brain — which typically loses some mass over time as we age — actually increased in size.1

The researchers put half of the 120 study participants, all between the ages of 55 and 80, through their paces.  They went from a sedentary lifestyle to a walking routine, steadily increasing the frequency and duration of their walks.  This group worked their way up to 40 minutes at a time, three times per week, which was enough to ensure an elevated heart rate.  The remaining 60 participants focused on weight training, yoga, and stretching activities for 40 minutes, three times each week, with no cardiovascular exercise included.

After a year, those in the toning group experienced the loss of a bit more than one percent of the volume of the anterior hippocampus of their brains — a normal amount of shrinkage that comes with aging.  However, the volunteers who had been walking had approximately a two percent increase in the volume of the anterior hippocampus of their brains.  In addition, the aerobic exercisers achieved higher scores in memory testing, which makes sense since the hippocampus is a memory center in the brain.  They also were found to possess more neurotrophic factor (BDNF), which is a protein in the brain that helps neurons to grow and survive.  A lack of BDNF has been found in Alzheimer’s patients.

Aside from being a memory center, the anterior hippocampus is a part of the brain that can produce new nerve cells from adult stem cells all through one’s life.  This could possibly explain the increase in volume found in this study, but more research needs to be done to determine whether that’s the case.

This research shows that aerobic exercise is clearly more beneficial to brain function than toning workouts, so it stands to reason that maybe more energetic activity [2] would be even better than walking.  Unfortunately, the logic here does not pan out.  A 2009 study at the University of Toronto found that women who participate in vigorous aerobic exercise for decades experience significant cognitive decline and are at increased risk for dementia.2  Some of the activities that upped participants’ risk of cognitive problems were long-distance running, biking up hills, aerobics, racquetball, and swimming.

The 90 women involved in the study, between the ages of 50 and 63, were given eight cognitive function and memory tests.  Those who participated in the most strenuous forms of exercise performed the worst on all of the mental tests.  On average, the heavily exercising group had engaged in 2.5 hours of vigorous exercise weekly.  The impairment showed up most dramatically in tests of memory, attention, and recall.  And in a separate study involving exercising rats, the longer and farther the rats ran on a treadmill, the more damage was done to their brains, especially the hippocampus.

What it seems to come down to is that it’s important to exercise regularly without overdoing it.  You don’t need to train like you are entering a marathon.  Make time for daily workouts but remember that moderation is key.  Get in some form of cardiovascular (or interval) activity, whether it’s walking, bike riding, jogging, or some other exercise that gets your heart pumping a little faster.  But don’t forget strength training and flexibility workouts too.  Just because they may not grow your hippocampus at all, don’t discount them.  Every type of exercise [3] can benefit your body and work to improve your overall health and well being.

1 Erickson, Kirk I.; Voss, Michelle W.; Prakash, Ruchika Shaurya; et al. “Exercise training increaes size of hippocampus and improves memory.” Proceedings of the National Academy of Sciences of the United States of America. 31 January 2011.  National Academy of Sciences. 9 May 2011. <http://www.pnas.org/content/108/7/3017.abstract?sid=456c5518-e10e-47d8-be7d-10b81e0f025c>.

2 Cassels, Caroline. “Moderate Physical Exercise, DASH Diet Protective Against Age-Related Cognitive Decline.” Medscape News Today. 29 July 2009.  Medscape, LLC. 10 May 2011. <http://www.medscape.com/viewarticle/706680>.