Making the Cognitive Leap: Exercise is Good for 'Chemo Brain'

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By Arash Asher, MD
Director, Cancer Survivorship and RehabilitationSamuel Oschin Comprehensive Cancer Institute Cedars-Sinai Medical Center, Los Angeles, CA

Fortunately, the scientific community has come a long way over the last several years in better understanding chemo brain, its causes, and how it can really impact a cancer survivor's life.  Unfortunately, we have much more work to do in learning about effective treatments for this problem.  
As a cancer rehabilitation physician who sees many patients struggling with chemo brain, I am very interested in finding ways to help the quality of life of patients with this problem.  I'd like to briefly discuss the possibility and benefits of using an old tool to help this newly recognized problem: EXERCISE.  
We all have heard about the many many benefits of exercise:  reducing heart disease, improving lung function, supporting our bones, strengthening our muscles, fighting depression, and on and on.  There is increasing evidence over the last decade that exercise may improve our memory and cognitive ability as well.  Nobody is exactly sure why exercise may improve our memory and cognitive ability.  Exercise seems to increase BDNF (brain-derived neurotrophin factor), which has been popularly referred to as the "fertilizer" of our neurons and helps improve the function and growth of our brain cells.  Exercise also improves the brain's blood flow, oxygen uptake, and glucose utilization (the main source of fuel for the brain) -- all ways that may explain exercise's benefits for our brain function  (Devine, 2009, "Physical Exercise and Cognitive Recovery in Acquired Brain Injury: a Review of the Literature"). 
Several interesting studies have demonstrated this idea (Colcombe, 2003, "Fitness Effects on the Cognitive Function of Older Adults: a Meta-Analytic Study").  In one study for example, healthy older adults were divided into two groups: one group participated in an aerobic exericse program for 6 months and the other only practiced a stretching regimen in 6 months.   At the end of the study, the aerobic intervention group performed much better in testing of their attention system, memory, and executive function.  
Perhaps even more interestingly, this study also included a functional MRI of the brain (which lights up areas of the brain that are activated) before and after the intervention.  They found that the aerobic exercise group actually showed improved activity in the areas of the brain responsible for attention and executive function, providing more concrete evidence that exercise actually changes the way our brains are wired and how well it functions  (Colcombe, 2004, "Cardiovascular Fitness, Cortical Plasticity, and Aging").
Other studies have  suggested that incorporating resistance training exercises (such as weight training) with aerobic exercises provides better results  than aerobic training alone (Smith PJ, 2010, "Aerobic Exercise and Neurocognitive Performance: a Meta-Analytic Review of Randomized Controlled Trials").
The major caveat of all the studies looking at exercise and memory: patients with chemo brain have NOT been studied yet.  Therefore, we can't assume that these benefits  are  generalizable to people with  chemo brain. But, given all the other benefits of exercise for cancer survivors that have been proven, I routinely try to outline a safe exercise program for all my patients having chemo brain symptoms.
For more information about the Cancer Survivorship and Rehabilitation Program at Cedars-Sinai Medical Center, click here or call (310) 423-2111.