Author(s): FERON, J., RAHMAN, F., FOSSTVEIT, S., JOYCE, K., GILANI, A., LOHNE-SEILER, H., BERNSTEN, S., MULLINGER, K., SEGAERT, K., LUCAS, S., Institution: UNIVERSITY OF BIRMINGHAM, Country: UNITED KINGDOM, Abstract-ID: 2115

INTRODUCTION:
Brain vascular health worsens with age, evident by cerebral blood flow (CBF) reductions and lengthening arterial transit time (ATT) (1). Furthermore, low CBF is associated with accelerated cognitive decline in older adults (2). Exercise training can improve aspects of brain health in older adults, including cognitive function (3) and grey matter volume (4), yet its effects on CBF and ATT remain unclear (5). The aim of this study was to assess the impact of exercise training on CBF and ATT in older adults, and determine whether CBF or ATT are important for cognitive function.
METHODS:
This randomised controlled trial involved a 26-week home-based exercise intervention in healthy older adults (n=65, aged 60–81 years). Multi-delay (200, 975, 1425, 1850, 2025, 2150, 2250, and 2300 ms) pseudo-continuous arterial spin labelling (pCASL) MRI was used to estimate global and regional CBF and ATT in grey matter. Cardiorespiratory fitness (V̇O2peak) was determined with an incremental treadmill test to exhaustion. Mixed design ANOVAs with age and sex as covariates assessed between-group differences and multiple linear regressions with ΔCBF or ΔATT as the dependant variable assessed associations with changes in cardiorespiratory fitness (model: age, sex, ΔBMI, ΔV̇O2peak) and cognitive function (model: age, sex, education, Δprocessing speed, Δworking memory, Δattention).
RESULTS:
Results showed that cardiorespiratory fitness increased in the exercise group (7.7±10.0 Δ%), but not in the controls. There were no between-group differences in CBF or ATT following the intervention. There was an association between the change in cardiorespiratory fitness and the change in global CBF within the exercise group (β=-0.36 [-0.71, -0.02]), whereby cardiorespiratory fitness gains were associated with declines in CBF. Cognitive function did not significantly change in either group, nor were cognitive function changes associated with changes in CBF or ATT.
CONCLUSION:
Exercise is generally considered to be beneficial for brain health in ageing (6), but the present data indicate that changes in resting cerebrovascular haemodynamics may not be the most important contributor. More substantial cerebrovascular changes may be seen with longer or different types (e.g., weight-loss) of interventions.

References
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4. Erickson, K. I. et al. Neurobiol Aging. 2014.
5. Kleinloog, J. P. D. et al. J. Int J Sport Nutr Exerc Metab. 2023.
6. Voss, M. W. et al. Journal of Applied Physiology. 2011.