Short-term effect of low intensity forced aerob exercise added to conventional physiotherapy on cognitive functions and fitness after stroke: A randomized controlled pilot study

Abstract

Emerging experimental and clinical findings suggest that aerob forced exercise may potentially have positive benefits on cognitive functions. The purpose of our pilot study was to assess the effect of low intensity aerobic exercise on cognitive functions in individuals with chronic stroke. Thirty-five chronic, ambulatory stroke patients aged between 33 and 76 years old completed the 4-week program, 90 min session/day in every workday. They were randomized into two groups: study group (SG, n = 19, median age 59/40–76/) years and control group (CG, n = 16 median age 62/33–69/) years. Both groups participated in conventional physiotherapy but only SG performed aerob exercise training with bicycles (30 min/day). Exercise intensity progressed from 30 to 40% of heart rate reserve defined by ergospiromety. Functional Independence Measure (FIM-cognitive) and Wechsler Adult Intelligence Scale processing speed (symbol search, coding) and working memory (digit span forward, backward and sequencing) subtests were recorded at baseline and 4 weeks later. Maximum oxygen intake (VO 2max ) was measured at baseline and 4 weeks later. Inside group analysis showed a significant improvement in both groups in cognitive-FIM ( P = 0.008). A significant change was not found in working memory (digit span) subtest ( P = 0.16) in either of the groups. In processing speed subtest (coding) a significant improvement was only measured in SG ( P = 0.003) while in a symbol search test an improvement was found in both groups (SG: P = 0.041, CG: P = 0.006). There were not inter-group differences in any subtest (all P = 0.201) and in VO 2max ( P = 0.8). Any significant improvement in VO 2max was not found in either of the groups ( P = 0.7). The results suggested that low intensity aerobic exercise training integrated into conventional stroke rehabilitation program had effects on the selected measures of cognitive functions, nevertheless the VO 2 max remained unchanged. Further studies are needed to get evidence with sufficient power.