As someone who is a little bit of a gym fanatic (to put it mildly) and has a research program investigating the impacts of chemotherapy on the brain, I wanted to write my next blog on the impact of exercise on symptoms of this condition. I especially wanted to pick apart what we know about the impact of different types of exercise on symptom severity.
Many patients with cancer report issues with remembering, thinking and multi-tasking either during or after their cancer treatment. These ‘cognitive’ issues are often called ‘chemobrain’ or ‘chemofog’. In spite of the name it is not just chemotherapy that causes this condition; cancer itself, radiotherapy and hormonal treatments have all been linked with it. The stress and fatigue brought about by a cancer diagnosis and treatment are also factors.
Whilst only a few studies have looked at cognitive decline as a primary outcome, there is certainly some evidence of a beneficial effect of exercise based on animal and human studies. A recent systematic review brought together the evidence from 29 studies involving patients diagnosed with a range of cancer types. A range of different exercise activities were performed. Importantly, this review only selected studies where there was a suitable control group. This gives us more confidence in the study findings as these are strong study designs. Only 45% of the studies included in this review showed that patients had improved cognitive function following exercise. However, many of these studies were not looking at cognitive function as the study goal, instead it was a secondary outcome. As a result, the studies may not have recruited enough patients to be able to come to a reliable conclusion.
A later review focused on breast cancer patients, found that exercise impacted some aspects of cognition but not others. As an example, exercise reduced mental fatigue and improved problem solving, but did not improve memory or processing speed.
There are a range of possible reasons why exercise may be beneficial. Exercise causes the release of substances in the brain which help grow nerves in the brain and even cause enlargements to brain areas which control cognitive functions. Exercise also reduces fatigue, and depression and anxiety, all of which can lead to impaired cognition.
So what kinds of exercise are most valuable? Well it appears that all types of exercise could help, including aerobic or cardio exercise, weights-based training, or mind-body workouts, such as yoga or tai-chi. However, the greatest benefits come from doing aerobic exercise of a moderate to high intensity.
Whilst this topic needs further research, there is increasing evidence that exercise can improve symptoms of chemobrain. What’s more, we know of all the other beneficial effects of exercise on cardiovascular function and on mental health. So, if patients feel able to exercise they will likely reap the rewards in several ways.
But it’s important to remember that most of us are not naturally strong or fit, it takes time and conditioning after any break in exercising. Listen to your body, and speak to your oncologist, qualified trainers, or an exercise physiologist about what’s right for you.
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