C.-H. Liu1, T.-L. Lei2, P.-F. Tang1,2,3,4,5, S.-Y. Chen3,6, J. Goh2,4,5,7, Y.-L. Chang4,5,7,8, Y.-F. Chen9,10, W.-Y. Tseng2,4,11,12, J.-H. Chen13,14, Y.-T. Hung1
1National Taiwan University, School and Graduate Institute of Physical Therapy, College of Medicine, Taipei, Taiwan, 2National Taiwan University, Graduate Institute of Brain and Mind Sciences, College of Medicine, Taipei, Taiwan, 3National Taiwan University Hospital and National Taiwan University College of Medicine, Department of Physical Medicine and Rehabilitation, Taipei, Taiwan, 4National Taiwan University, Neurobiology and Cognitive Science Center, Taipei, Taiwan, 5National Taiwan University, Center for Artificial Intelligence and Robotics, Taipei, Taiwan, 6Fu Jen Catholic University Hospital and School of Medicine, Fu Jen Catholic University, Division of Physical Medicine & Rehabilitation, Taipei, Taiwan, 7National Taiwan University, Department of Psychology, College of Science, Taipei, Taiwan, 8National Taiwan University Hospital, Department of Neurology, Taipei, Taiwan, 9National Taiwan University Hospital, Department of Medical Imaging, Taipei, Taiwan, 10National Taiwan University Hospital Hsin-Chu Branch, Department of Medical Imaging, Hsin-Chu, Taiwan, 11National Taiwan University, Institute of Medical Device and Imaging, College of Medicine, Taipei, Taiwan, 12National Taiwan University, Institute of Biomedical Engineering, Taipei, Taiwan, 13National Taiwan University Hospital, Department of Geriatrics and Gerontology, Taipei, Taiwan, 14National Taiwan University Hospital, Department of Internal Medicine, Taipei, Taiwan

Background: Cardiorespiratory fitness (CRF) and cognitive functions are known to be worse in people with cardiovascular risks (CVRs), compared to those without. Regular exercises are beneficial for improving CRF and cognition, and reducing CVRs in adults with CVRs. However, little research has examined the relationships of improved CRF and CVRs with changes in executive functions in people with CVRs after different types of exercise training.

Purpose: We examined the relationships of improved CRF and biomarker of CVRs with changes in executive functions in middle-aged and older adults with CVRs after a 24-week Aerobic or Stretching/Breathing exercises training ( identifier: NCT03275038).  

Methods: We recruited 69 cognitively normal adults (Montreal Cognitive Assessment score ≥ 24, age range= 45-78 years) with CVRs of hypertension, dyslipidemia, diabetes mellitus, or any combination of these risks. All participants were stratified by age and sex and randomly assigned to the Tai-Chi-Chuan (TCC), Aerobic, or Stretching/Breathing exercise group. They underwent a cardiopulmonary exercise test (CPET) to measure their CRF parameters, a blood test to measure their CVRs, a spatial span (SSP) test to measure their working memory function, and a numerical Stroop test to measure their task-switching performance before and after the 24-week training. All the training groups received three one-hour light-to-moderate intensity exercise sessions for 24 weeks. Partial correlations were performed to investigate the relationships of improved CRF and CVR measures with changes in executive functions for each group, controlling for sex, age and education. Data were analyzed using the intention-to-treat (ITT) analysis.

Results: There were 22, 23, and 24 participants assigned to the TCC (64.2±7.5 y/o), Aerobic (64.4±8.0 y/o), and Stretching/Breathing (65.3±6.4 y/o) groups, respectively. Due to the high drop-out rate (22.7%) of the TCC group, we performed ITT analyses on the Aerobic and Stretching/Breathing groups only and reported their results here. After the 24-week training, for the Aerobic group, greater improvement in the peak oxygen uptake during CPET was associated with greater reduction of error rate in the switch cost (SC) of the numerical Stroop test (r= -0.466, p= 0.038); and greater increases in high-density lipoprotein cholesterol (HDL-C) were associated with greater error rate reductions in the switch condition (r=-0.678, p=0.001) and in SC (r= -0.578, p= 0.008) of the numerical Stroop test. For the Stretching/Breathing group, greater reductions of the homocysteine level were associated with increases in the SSP length (r= -0.477, p= 0.029).

Conclusion(s): Our findings showed that after 24-week exercise training, greater improvements on CRF and HDL-C were associated with better task-switching performance after aerobic training, whereas greater improvements on the homocysteine level were associated with greater improvements in the spatial working memory after Stretching/Breathing. 

Implications: These findings suggest that greater improvements on CRF measures and biomarkers of CVRs were both associated with improvements in executive functions after exercise training in middle-aged and older adults with CVRs. Hence, regular exercises could help this population to have better executive functions perhaps through maintaining better CRF and controlling CVRs. However, the causal relationships or underlying mechanisms need further explorations.

Funding, acknowledgements: This work was supported by the Ministry of Science and Technology (Grant No. 106-2314-B-002-086-MY3) awarded to Dr. Pei-Fang Tang.

Keywords: Cardiorespiratory Fitness, Executive functions, Cardiovascular Risks

Topic: Cardiorespiratory

Did this work require ethics approval? Yes
Institution: National Taiwan University Hospital (NTUH)
Committee: Research Ethics Committee (REC)
Ethics number: 201612213RINB

All authors, affiliations and abstracts have been published as submitted.

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