The Impact of Acute Aerobic Exercise on Attention and Brain‐Derived Neurotrophic Factor in Breast Cancer Survivors

The purpose of this investigation was to examine the effect of one bout of moderate intensity aerobic exercise on attention and serum levels of brain‐derived neurotrophic factor (BDNF) in women with a history of breast cancer. Study participants included 9 women between the ages of 45–75 years who had completed treatments for Stage I–III invasive breast cancer prior to enrollment. Participants completed a 30‐minute session of aerobic exercise on the cycle ergometer at 60% of VO 2peak . Before and after the 30‐minute aerobic exercise session, participants completed two computerized tests of attention: the Digit Span Test and the Flanker Task (Inquisit, Millisecond Software, LLC, Seattle, WA). Performance on the Digit Span was assessed by examining the mean forward digit span and mean backward digit span achieved. Performance on the Flanker Task was assessed by examining the error proportion and mean reaction times for incongruent and congruent trials. Whole blood samples were taken pre‐exercise, immediately post‐exercise, and immediately following completion of the post‐exercise Digit Span and Flanker Task. Serum BDNF levels were assessed at each time using enzyme‐linked immunosorbent assay (ELISA) techniques (R&D Systems Inc., Minneapolis, MN). Repeated measures ANOVAs indicated that participants tended to achieve better performance on the forward digit span compared to the backward digit span for both the pre‐ and post‐exercise administrations ( Table 1, p = 0.064). Participants also tended to have lower error proportion scores for the congruent vs. the incongruent trials of the Flanker Task for both the pre‐exercise and post‐exercise administrations ( Table 2, p = 0.090) while displaying improved reaction time from pre‐ to post‐exercise during both the incongruent and congruent trials ( Table 2, p = 0.003). Serum BDNF levels were similar from pre‐exercise to the two post‐exercise time points (35,630 ± 12,807 pg/mL vs. 33,538 ± 14,032 pg/mL vs. 35,892 ± 8179 pg/mL; p = 0.615–0.990). These results suggest that one 30‐minute session of moderate intensity aerobic exercise may positively impact some aspects of attention in women with a history of breast cancer, although biomarkers of cognitive function (i.e. serum BDNF) may not be significantly affected. Understanding the effect of aerobic exercise on cognitive function in breast cancer survivors may yield insight into devising therapeutic approaches to alleviate the impact of cancer therapies on cognitive function in this population. Support or Funding Information This work was supported by Elon University Faculty Research and Development funds. 1 Mean Digit Span Results (mean ± SD)Digit Span Direction Pre‐exercise Mean Digit Span a Post‐exercise Mean Digit Span aForward 6.59 ± 1.26 6.80 ± 1.15 Backward 5.38 ± 1.20 6.14 ± 2.27a p = 0.064 for comparing forward mean digit span vs. backward mean digit span2 Error Proportion and Mean Reaction Time Results for the Flanker Task (mean ± SD)Flanker Task Trial Error Proportion a Mean Reaction Time (ms)IncongruentPre‐exercise 0.099 ± 0.036 597.8 ± 60.5 b Post‐exercise 0.215 ± 0.280 555.6 ± 50.9 bCongruentPre‐exercise 0.080 ± 0.032 588.5 ± 48.7 c Post‐exercise 0.207 ± 0.292 548.3 ± 53.6 ca p = 0.090 for comparing the proportion of errors made on the incongruent vs. the congruent trials b p < 0.001 and c p = 0.026 for comparing pre‐exercise to post‐exercise mean reaction time for the incongruent and the congruent trials