Wednesday, December 14, 2011

Exercise and Brain Health


Here’s a hypothetical question for you.  When you get older would you rather A) have a healthy body and have dementia or Alzheimer’s, or B) become extremely physically handicapped while maintaining fully functioning faculties, or C) maintain a robust physical presence while still being as sharp upstairs as you ever were.  The obvious answer is C, but more often than not people will fall into either the A or B column.  The positive effects of exercise in staving off the effects of Father Time on your body are obvious and plentiful.  But the positive effects of exercise on brain health are only recently being recognized.

Alzheimer’s disease, the most common form of dementia, affects the areas of the brain that control memory, speech, and thought and can seriously impair a person’s ability to carry out day-to-day tasks.  The CDC estimates that about 5.4 million Americans are currently suffering from Alzheimer’s disease.  The number of Alzheimer’s patients has doubled since 1980 and is expected to be at 16 million by 2050.  In 2011 the total cost of Alzheimer’s disease is expected to be around $130 billion.  About 5% of people aged between 65-74 years are affected by Alzheimer’s with that number jumping to 50% or people 85 years and older.

The exact cause of Alzheimer’s is still unclear.  It probably includes several factors that play different roles in each individual affected by the disease.  Scientists have uncovered several risk factors for the disease with age being number one.  Other factors include family history of the disease and risk factors that are similar to those of cardiovascular disease such as high blood pressure and cholesterol and low levels of folate.  Researchers are also starting to uncover some routes for preventing and slowing the progress of the disease once it is diagnosed.

Many studies have begun to show the positive correlates of exercise to brain health, especially in patients with Alzheimer’s disease.  In one study each patient was assigned to either a walking group or non-walking group.  Each patient was administered a mental state examination.  At the end of the study the walking group, in addition to improving walking times, had a much slower decline on the mental state examination (47% for the non-walking group to just 13% for the walking group.)  Studies have shown that exercise increases a cells endurance and resistance to oxidative stress and has positive effects on neurogenesis (growth of new nerve and brain cells) and memory improvement.

Exercise also seems to help improve symptoms in patients diagnosed with depression.  In a study done on treatment-resistant patients, moderate to intense exercise improved depressive parameters and functioning.  Exercise also contributed to the remission of 26% of the patients enrolled in the study.  Although the effects are promising exercise is still only a supplement to normal treatment measures.  In a study that investigated whether or not exercise decreased the risk of post-partum depression in women the only group of subjects that showed statistically significant benefits were those mothers that were not active prior to being pregnant.  In another meta-analysis of the literature on the role of exercise and depression most of the benefits were not statistically significant and more studies were needed.  But just because data isn’t statistically significant doesn’t mean there isn’t something to be gained from it.

Despite what the literature says I can speak from my experience and from the experience of others that exercise can be beneficial for brain health and mood regardless of age or current mental state.  When things aren’t going your way and you feel the weight of the world on you exercise can be there as a way to exorcise (pun intended) some of your demons.  It can be there to be the one thing in your life that you can control.  It can be like a steady ship in a stormy ocean.  Speaking for myself I know that when life throws me a few curves and I can’t get my normal lifts in I’m not the same person I usually am.  Small annoyances go from being mole hills to mountains.  In other words I get a serious case of the Crabapple McNasties.  And once I get back into the gym and hoist some heavy poundages my worries seem to shrink and oftentimes disappear entirely.

The data on Alzheimer’s disease, dementia, and exercise is compelling to say the least.  If something as simple as walking a few times per week can slow the progression of the disease I would think that being active from an early age on would have a beneficial effect as well.  I would like to see some longitudinal studies done on the protective effects of exercise, but for right now make sure you are getting in some good exercise a few times a week and constantly surround yourself with people you care about.  And don’t forget to break a mental sweat every now and again, too.

Sources:


Exercise plays a preventive role against Alzheimer's disease.  Radak Z, et al. J Alzheimer’s Dis. 2010;20(3):777-83.

 Six-Month Walking Program Changes Cognitive and ADL Performance in Patients With Alzheimer.  Venturelli M, et al. Am J Alzheimers Dis Other Demen. 2011 Aug 17.

Exercise-induced cognitive plasticity, implications for mild cognitive impairment and Alzheimer's disease.  Foster PP, et al.  Front Neurol. 2011;2:28. Epub 2011 May 6.

Moderate exercise improves depression parameters in treatment-resistant patients with major depressive disorder.  Mota-Pereira J, et al. J Psychiatr Res. 2011 Aug;45(8):1005-11.

Does exercise during pregnancy prevent postnatal depression?: A randomized controlled trial. Songøygard KM, et al.  Acta Obstet Gynecol Scand. 2011 Sep 1. doi: 10.1111/j.1600-0412.2011.01262.x.

Exercise for depression.  Mead GE, et al.  Cochrane Database Syst Rev. 2009 Jul 8;(3):CD004366. 

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