Dementia is one of the leading causes of disability worldwide. Underlying biological mechanisms are crucial in preclinical stages of Alzheimer’s disease (AD). Alterations in cerebral blood flow (CBF) and their relationship with AD blood-based biomarkers may be fundamental at early stages of the pathology. Notably, physical exercise is one of the most promising non-pharmacological interventions to delay the onset of dementia and slow down the progression of cognitive decline. Therefore, flADex aims to examine the acute effects of different types of exercise on CBF, AD blood-based biomarkers, and its cognitive implications in cognitively normal older adults.
FlADex is a counterbalanced crossover trial that will include 20 adults aged 68 to 83 with negative brain amyloid status (<12 centiloid) and APOE e4 noncarriers. Each participant will be included in all study conditions in a randomized order: (i) moderate aerobic exercise (between 40-60% of Heart Rate of Reserve); (ii); resistance exercise and (iii) resting condition. Each condition, lasting 30 minutes, will be performed once. CBF will be assessed by magnetic resonance imaging using pseudo-continuous arterial spin labeling at pre- and at 3 consecutive times post-condition (at 10, 16,22). AD blood-based biomarkers (Aβ42, Aβ40, p-tau217, p-tau181, GFAP, NfL) will be measured pre-condition and post-condition (at 0, 40, 60 min), via the SIMOA platform (Quanterix, Billerica, MA) Cognitive outcomes (flanker test and picture sequence memory test) and mood status (POMS questionnaire) will be measured pre and post condition.
FlADex trial will shed light on the acute effects of different types of exercises on CBF and AD blood-based biomarkers before the beta-amyloid accumulation. We expect that aerobic and resistance exercise will have different effects on CBF dynamics and AD blood biomarker levels over time in cognitively normal older adults
