Poster E42, Saturday, August 18, 3:00 – 4:45 pm, Room 2000AB

The effects of different exercise intensities on word learning in ageing: a randomised controlled trial.

Marie-Pier Mc Sween1,2,3,4, Katie L. McMahon3, Jeff S. Coombes4, Kylie Maguire4, Amy D. Rodriguez1,5, Kirk I. Erickson6, David A. Copland1,2;1School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Australia, 2UQ-CCR, The University of Queensland, Brisbane, Australia, 3Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia, 4School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia, 5Centre for Visual and Neurocognitive Rehabilitation, Department of Veterans Affairs, Atlanta, USA, 6The Department of Psychology, The University of Pittsburgh, Pittsburgh, USA.

Background: There is increasing interest in whether exercise can be used to address age-related cognitive decline and enhance cognitive recovery after neurological injury. Recent studies show positive impacts of acute exercise on aspects of cognition including language learning and memory. In healthy young adults, a single bout of intense physical exercise has been shown to benefit vocabulary learning when compared to a sedentary or moderate intensity exercise group. However, it is not known whether these effects also occur in healthy older adults and the level of exercise intensity necessary to enhance new word learning in healthy older adults is yet to be established. Thus, the aim of this study was to investigate the effects of different intensities of acute exercise on new word learning performance of healthy older adults. Methods: Sixty healthy older adults (mean age= 66; range= 60-78; gender= 43F/17M) were recruited to participate in this between-group randomised controlled trial. Participants attended three visits within a 3-week period and completed baseline cognitive assessments (including a baseline word learning task) and fitness assessment (VO2peak). Moreover, participants engaged in either stretching (38 minutes), moderate-intensity cycling (30 minutes at 55-65% Heart Rate (HR) max), or high-intensity cycling (4x4 minutes at 85-95% HRmax interspersed with 3x3 minutes at 50-65% HRmax), followed by an associative word-learning task in which 15 familiar objects paired with legal non-words were randomly presented in five blocks. A recall task was completed after each block. Blood samples were taken immediately before exercise, after exercise and after word learning. Results: Proportional data were arcsine transformed and then submitted to repeated measures ANOVA with recall accuracy as the dependent variable, intervention group and recall trial (1-5) as independent variables and VO2peak and baseline word learning performance as covariates. Preliminary analyses of immediate recall data (trials 1-5) showed a significant three-way interaction between recall trial, intervention group and baseline word learning performance (F(7.5, 121.052)=7.512, p<0.005, η²=0.320). In participants with lower baseline word learning performance, there were main effects of recall trial (F(4, 88)=7.267, p<0.005, η²=0.248) and intervention group (F(2, 22)=6.041, p=0.008, η²=0.355), with recall accuracy in the moderate and high intensity groups being superior to the stretching group. In low baseline performers, there was also a significant interaction between intervention group and VO2peak (F(3, 22)=4.520, p=0.013, η²=0.381). However, in participants with higher baseline word learning performance, there was no effect of recall trial, intervention group or interaction between intervention group and VO2peak. Conclusion: This study was the first to investigate different intensities of acute exercise, including high-intensity interval training, on new word learning success in healthy older adults. The results suggest an overall interaction between intervention and immediate word learning performance, however, this influence of exercise varies as a function of baseline word learning capacity and does not favour a specific intensity level. Further analysis of the relationship between exercise-induced changes in biomarker levels and word learning success will provide information on potential underlying neurophysiological mechanisms responsible for exercise-induced word learning enhancement in healthy older adults.

Topic Area: Language Therapy

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