Zimmer, P., Baumann, F.T., Oberste, M., Wright, P., Garthe, A., Schenk, A., . . . Wolf, F. (2016). Effects of exercise interventions and physical activity behavior on cancer related cognitive impairments: A systematic review. BioMed Research International, 2016, 1820954. 

STUDY PURPOSE: To evaluate the effectiveness of an exercise intervention and physical activity behavior on cancer-related cognitive impairment

TYPE OF STUDY: Systematic review

• FINAL NUMBER STUDIES INCLUDED = 19 (5 animal studies and 14 human studies) 
• TOTAL PATIENTS INCLUDED IN REVIEW = 1,560 patients and 226 rodents
• SAMPLE RANGE ACROSS STUDIES: 4–447 patients
• KEY SAMPLE CHARACTERISTICS: Although educational status may influence neuropsychologic test results, this information was not provided. Likewise, menopausal status may affect cognition; because 14 studies primarily consisted of patients with breast cancer (four studies included other tumor types), this was not reported.

PHASE OF CARE: Late effects and survivorship

In patients, studies of exercise interventions had mixed results regarding their effectiveness in improving cognitive function. Interventions reviewed included an undefined physical activity (n = 3), cardiovascular fitness (n = 1), home-based walking and resistance band training (n = 1), yoga (n = 3), speed-feedback therapy on a bicycle ergometer (n = 1), medical qigong (n = 1), physical activity behavior change program (n = 1), Tai chi (n = 1), progressive aerobic endurance training on a treadmill (n = 1), and strength training (n = 1). Although the review reported cross-sectional studies that revealed correlations between physical activity with visual memory (n = 1), executive function (n = 1), attention (n = 1), and information processing (n = 1), the strength of these correlations was not reported. Randomized, controlled trial studies reported improved perceived cognitive functioning with walking, yoga, and medical qigong but not with the physical activity behavior change program. In addition, improvements were found for executive function with speed-feedback therapy, attention and verbal memory (but not working memory with strength training), and memory with yoga. However, in each of these results, the significance of these findings was not reported. These results are further complicated by the lack of consistency in regard to the cognitive functioning measures used.

Exercise may improve perceived cognitive function. However, further research is needed to validate if specific types of exercise affect cognitive functioning and to determine the dose or duration required for a durable response. Longitudinal studies with larger sample sizes that incorporate both objective and subjective measures of evaluating cognitive function are needed before recommendations for exercise can be made as a means to counteract chemotherapy-related cognitive impairment.

• High heterogeneity
• Low sample sizes
• A small number of studies with humans (n = 14) was included in the review for multiple types of exercise and physical activity interventions.  
• Studies of low quality were included.

The findings suggest that some forms of exercise or physical activity interventions may be helpful in improving patients’ perception of chemotherapy-induced cognitive impairment; however, these findings are based on a small number of studies per intervention. Recommendations cannot be made based on this review.