Sex differences in the effects of exercise on cognition post-stroke: Secondary analysis of a randomized controlled trial

Abstract

LAY ABSTRACTExercise can improve thinking and memory in people with stroke, but we do not know if men and women improve to the same degree. This study examined whether there were differences in thinking and memory between men and women with stroke after 6 months of aerobic or balance/flexibility exercise. Volunteers were randomly assigned to a 6-month aerobic exercise programme or a balance/flexibility exercise programme. Thinking and memory skills were tested before and after the exercise programme. Women did better then men on a test of attention and problem-solving after exercise. There were no differences between men and women in any other test. These findings show that exercise may be better for improving attention and problem-solving in women living with stroke than in men.Objective: To determine whether there are differences in exercise-associated changes in cognitive function between males and females living with stroke. Design: Secondary analysis of data from a prospective assessor-blinded randomized controlled trial. Participants: Fifty participants (50-80 years, > 1 year post-stroke, able to walk ≥ 5 m). Methods: Participants were allocated into a 6-month aerobic exercise programme (14 males, 11 females) or balance and flexibility programme (15 males, 10 females). Working memory (Verbal Digit Span Backwards Test), selective attention and conflict resolution (Stroop Colour-Word Test), and set shifting/ cognitive flexibility (Trail-Making Test B) were assessed before and after the programmes.Results: There was a group × time interaction in females (effect size 0.28, p = 0.03), which was not observed in males (effect size 0.01, p = 0.62). Females demonstrated a Stroop Colour-Word Interference test change of -2.3 s, whereas males demonstrated a change of +5.5 s following aerobic exercise. There were no differences between exercise groups in either sex for any of the other outcomes (working memory and set-shifting/cognitive flexibility). Conclusion: Females living with stroke may demonstrate a greater response to exercise on selective attention and conflict resolution compared with males with stroke. These findings suggest that there may be sex-specific effects of exercise on cognitive function in individuals with stroke.

Is High-Intensity Interval Training Suitable to Promote Neuroplasticity and Cognitive Functions after Stroke?

“…Interestingly, when neuroblastic rat cells in culture are treated with the serum from individuals with stroke achieving HIIT, it results in a higher increase of dendritic growth and mitochondria redistribution along these new dendrites [35]. Other authors also found very low effects of long-term "high-intensity training" (not HIIT in this study) on short-term memory without altering working memory and executive functions [23,27]. Indeed, Tang et al, showed no effect on working memory, attention and conflict resolution when exercise intensity progressively increased from 40 to 80% of HR reserve over 3 ➚ Serum BDNF after HIIT ➚ Dendritic growth with patient serum after HIIT ➚ indicate an increase; ⟺ indicate a maintenance; BDNF: brain-derived neurotrophic factor; VEGF: vascular endothelial growth factor; IGF-1: insulin-like growth factor 1; HRR: heart rate reserve; HI: high-intensity; LI; low-intensity; HIIT: high-intensity interval training; MICT: moderate-intensity.…”

“…Interestingly, when neuroblastic rat cells in culture are treated with the serum from individuals with stroke achieving HIIT, it results in a higher increase of dendritic growth and mitochondria redistribution along these new dendrites [ 35 ]. Other authors also found very low effects of long-term “high-intensity training” (not HIIT in this study) on short-term memory without altering working memory and executive functions [ 23 , 27 ]. Indeed, Tang et al, showed no effect on working memory, attention and conflict resolution when exercise intensity progressively increased from 40 to 80% of HR reserve over 3 months of training by using the Verbal Digit Span Test, Color-Word Stroop test and Trail-Making Test Part B [ 23 ] ( Table 1 ).…”

“…Exercise regimens with higher intensities, such as high-intensity interval training (HIIT), emerge as encouraging alternatives to improve cardiovascular and brain health following stroke [ 24 , 25 , 26 , 27 ]. HIIT, the most popular trend of 2018 [ 28 ], involves repeated short-to-long bouts of high-intensity exercise interspersed with active or passive recovery periods [ 29 ].…”

Cognitive Gains of Aerobic Exercise in Patients With Ischemic Cerebrovascular Disorder: A Systematic Review and Meta-Analysis

“…And there were more men when considering the total number of participants. The secondary analysis of Tang's study also found female stroke survivors benefited more in set shifting and response inhibition (Khattab et al, 2019). Females had greater progression in white matter hyperintensity while this change in males was not significant according to report from Liu-Ambrose (Dao et al, 2019).…”

“…A total of 80 articles were retrieved for fulltext review. There were two studies producing more than one publication (Tang et al, 2014(Tang et al, , 2016Liu-Ambrose et al, 2016;Hsu et al, 2017Hsu et al, , 2018Dao et al, 2019;Khattab et al, 2019), they were regarded as one study in the quantitative analysis. One publication (Rosenfeldt et al, 2019) was the secondary analysis of two randomized controlled trials (ClinicalTrials.gov registration numbers NCT02076776, National Institutes of Health, and NCT02494518, American Heart Association).…”