Women diagnosed with breast cancer who exercised before, during, and after chemotherapy were less likely to have thinking and memory problems, commonly called chemo brain.
The research was published online on Aug. 18, 2021, by the Journal of Clinical Oncology. Read the abstract of “Physical Activity Patterns and Relationships With Cognitive Function in Patients With Breast Cancer Before, During, and After Chemotherapy in a Prospective, Nationwide Study.”
What is chemo brain?
Many people who are receiving breast cancer treatment say they have issues remembering, thinking, and concentrating during and after treatment. People commonly call these issues chemo brain or chemo fog, while doctors call these issues cognitive impairment or cognitive problems. It’s important to note that people who receive hormonal therapy may also have memory problems.
Some people may have trouble with:
- learning new tasks
- remembering names
- paying attention and concentrating
- finding the right words
- organizing thoughts
- making decisions
- remembering where things are, such as keys or glasses
More than 75% of people diagnosed with breast cancer say they have cognitive problems during chemotherapy. In some cases, people can have cognitive problems several years after completing chemotherapy.
Because studies show that exercise can lead to better health outcomes and better quality of life in people diagnosed with cancer, the researchers who did this study wanted to see if exercise could help prevent chemo brain.
National physical activity guidelines
The U.S. Department of Health and Human Services (HHS) recommends that adults should do:
- at least 2.5 hours to 5 hours of exercise at moderate intensity per week; brisk walking is considered moderate intensity
- or 75 minutes to 2.5 hours of exercise at vigorous intensity per week; running or other high-intensity cardio is considered vigorous intensity
The HHS also recommends that adults should do muscle-strengthening exercises 2 or more days per week.
A number of organizations, including the American Cancer Society and the American College of Sports Medicine, have published exercise recommendations specifically for people living with and beyond cancer.
About the study
The study included 943 people:
- 580 people had been diagnosed with stage I-IIIC breast cancer, called the patient group
- 363 people had not been diagnosed with breast cancer, called the control group
Besides breast cancer, the two groups shared similar characteristics:
- the average age was about 53
- about 90% were white
- BMI ranged between 29 and 30
- about 30% were premenopausal and about 50% were postmenopausal
Of the breast cancers:
- 27.3% were stage I
- 49.1% were stage II
- 18.6% were stage III
- 5.0% were of an unknown stage
All the people diagnosed with breast cancer were scheduled to have chemotherapy:
- 45.9% were treated with a chemotherapy regimen that included an anthracycline
- 54.1% were treated with a chemotherapy regimen that didn’t include an anthracycline
Anthracycline chemotherapy medicines are:
- Adriamycin (chemical name: doxorubicin)
- Ellence (chemical name: epirubicin)
- Doxil (chemical name: liposomal doxorubicin)
- daunorubicin (brand names: Cerubidine, DaunoXome)
- mitoxantrone (brand name: Novantrone)
Anthracyclines work by damaging cancer cell genes and interfering with their reproduction. Studies have found a link between anthracycline chemotherapy medicines and cognitive problems.
The researchers assessed the participants’ cognitive function and amount of physical activity three times during the study:
- 7 days before chemotherapy started
- within 1 month after chemotherapy was completed
- 6 months after chemotherapy was completed
To assess cognition, the researchers used a combination of proven research tools and self-reports from the people in the study.
The researchers measured physical activity by having the people fill out questionnaires every 3 months. The researchers then calculated the metabolic equivalent of task (MET) of each activity and total METs per person per week.
The metabolic equivalent of task is a measurement of the energy used or calories burned during physical activity. One MET is the amount of energy you use while sitting quietly.
The researchers used the METs-per-week measurement to determine if each person fulfilled the current national physical activity guidelines.
At the first assessment, before chemotherapy started, about 33% of the patient group and about 43% of the control group met national guidelines for physical activity.
The study compared cognitive function between people in the patient group and people in the control group who met national physical activity guidelines. The researchers found that people in the patient group had similar cognition scores on the standardized tools, but still reported more cognitive problems than the people in the control group.
At the second assessment, about 1 month after chemotherapy ended, the number of people in the patient group meeting national physical activity guidelines dropped to 21%, but went back up to 37% at the third assessment, 6 months after chemotherapy ended.
The researchers found that people in the patient group who met the national physical activity guidelines at the first assessment were more likely to have better cognition scores over time than people in the patient group who didn’t meet the national physical activity guidelines.
Overall, people in the patient group who met the national physical activity guidelines at all three assessments were likely to have better cognition scores than people in the patient group who didn’t meet the physical activity guidelines.
“We’ve always believed that exercise is a great way to help cancer patients,” senior study author Michelle Janelsins, Ph.D., MPH, associate professor of surgery at the University of Rochester Medical Center, said in a statement. “But now we have evidence that meeting physical activity guidelines prior to getting chemotherapy has benefits. It puts you in fighting shape and appears to offer some protection against things such as memory difficulties or the inability to pay attention, which are common concerns for those undergoing chemotherapy.”
“Our findings contribute to the growing body of evidence highlighting the importance of physical activity as early as possible across the continuum of cancer care,” added first author Elizabeth Salerno, Ph.D., MPH, assistant professor of surgery at Washington University School of Medicine in St. Louis.
What this means for you
This study adds to the evidence showing that exercise can help boost cognition in people who are receiving breast cancer treatment.
While this study looked at links between exercise and cognition, there are many other benefits to regular exercise, especially if you’ve been diagnosed with breast cancer. Exercise can:
- lower the risk of breast cancer coming back (recurrence)
- help you maintain a healthy weight
- give more energy
- improve your mobility
- help you build more muscle mass and strength
- keep your bones healthy
- help you sleep better
Still, we know that if you’re receiving or recovering from breast cancer treatment — plus busy with work, household chores, and family matters — finding time to exercise almost every day can seem impossible.
It can help to break up exercise into 20- or 30-minute sessions that add up to 5 or more hours per week. Walking is a great way to start. You might consider walking 30 minutes in the morning and 30 minutes on your lunch break. You can add a few more minutes by parking farther away from where you work or getting out a stop before your usual if you take mass transit. Or you can make plans to walk with a friend — you’re more likely to stick with exercise if someone else is counting on you. Plus, you can socialize at the same time.
Read more about Exercise for tips on how to find the right exercise for you, exercise safely, and stick to an exercise routine.
To talk with others about the benefits of exercise, share exercise tips, and get encouragement, join the Breastcancer.org Discussion Board forum Working on Your Fitness.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical adviser
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