Monday, December 27, 2010

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

By Arash Asher, MD

Director, Cancer Survivorship and Rehabilitation
Samuel 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.


  1. Hi, specifically, what kind of exercise is best? Thanks.

  2. Nobody is exactly sure what the exact recipe calls for. Based on other studies looking at exercise for cancer-related fatigue, the best exercises include:
    1) a moderate intensity aerobic component. Aerobic exercises include things like swimming, walking, bicycling, rowing, etc. Keep in mind, 'moderate' means different things for different people. (i.e. moderate for me and moderate for Lance Armstrong are not the same). This is where speaking to a physician, exercise physiologist, etc. may be helpful.
    2) There's more and more evidence that resistance exercises, such as light weight training, may be very important as well. It seems that if we are able to maintain our muscle mass is very important to release certain chemicals into our body that may be protective.
    Hopefully there will be more specific recommendations in the future as more research is completed in this arena.

  3. I think it is becoming clear that exercise is just vital always. Now if I could only get my kids off the couch.

  4. I just joined an exercise class at my local cancer support center. I was diagnosed with stage 3A breast cancer in Dec. 2009. I am 42 years old and right now I feel like I could be 102 years old. I am hoping that this cancer exercise class will help point me in the right direction which is most helpful for my body and mind.

    When I was diagnosed, I had just started graduate school for speech pathology (a change of career). If I hadn't already taken two years of pre-reqs to get into the program, I probably would have not opted to start a new degree while going through surgery/chemo/radiation. Luckily I was not working. I have taken things slowly but wonder if I will ever be able to have a zest for life again. I owe it to myself and my three young daughters to read this book AND exercise regularly. I hope my new class sparks some energy in me.

    I look forward to reading your book and thank you for this blog.

  5. Dear TS,

    Don't get discouraged. Keep in mind that it has been just over one year since your diagnosis, AND as you say, you took on graduate work to boot. As you may know, I'm not a medical professional, just a journalist who writes about health and medicine (and I'm a breast cancer survivor like you), but from everything I've researched, physical exercise DOES seem to be key.

    I also would like to suggest that you ask your doctor about taking American ginseng for your fatigue. We write about this in "Your Brain After Chemo," focusing on some very positive results of a study out of the Mayo Clinic where a group of breast cancer patients showed dramatic improvements in their levels of fatigue and alertness.

    You'll find a summary of the study on page 148 of our book as well as information on where you can obtain this particular type of ginseng.

    Please write again and let us know how you're doing.

    All the best.