eBACH is a randomized intervention to determine the effects of aerobic exercise on brain structure and function, as well as to determine how exercise-induced training effects relate to cardiovascular function via related brain changes.
Aim 1: To determine the neurobiology of exercise and cardiovascular factors: (1A) Body- to -Brain hypothesis: Exercise -induced changes in peripheral markers of cardiovascular health (e.g., cardiorespiratory fitness, peripheral vascular function) will precede and partly explain (statistically mediate) some of the exercise -induced changes in functional and structural features of areas defining visceral control circuits. (1B) Brain- to -Body hypothesis: Exercise -induced changes in functional and structural features of areas defining visceral control circuits precede and partly explain (statistically mediate) consequent changes in autonomic and neuroendocrine mediators of cardiovascular function that are under neural regulation, including baro-reflex sensitivity and heart rate variability. Aim 2: To determine the neurobiology of exercise self--reported correlates of cardiovascular function: (2A) Exercise will induce changes in visceral control areas engaged by functional magnetic resonance imaging (fMRI) tasks, and these changes will partly explain exercise- induced reductions in cardiovascular responsivity to challenges in daily life. (2B) Exercise will induce changes in visceral control areas engaged by an functional magnetic resonance imaging (fMRI) emotion processing and regulation paradigm, and these changes will partly explain exercise- induced improvements in affect measured in daily life by EMA and by conventional self- report instruments. The public health significance of this research is that it is designed to more precisely define and refine neurobiological targets to improve cardiovascular function and health. Because of disruptions due to COVID-19, the study was placed into a compromised position that required conservation of funds and resources, resulting in a narrowing of focus and an abbreviated assessment protocol that limited the scale and scope of the longitudinal assessments and also reduced the sample size. As such, several of the secondary outcomes that were pre-specified were moved to "other pre-specified" during the course of the project.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
130
Guidelines for exercise programming (ACSM, 2018) will be followed including a warm up and cool down, progressive and gradual increments in duration, and instruction regarding avoidance of physical activity related injury. The exercise group will receive moderate to vigorous intensity aerobic exercise targeting 150 minutes per week for 12 months. The group will target dividing these minutes into 3 exercise sessions a week. The prescribed intensity will be based on their maximal fitness testing heart rate and then calculated per a research grade method. They will maintain a minimum heart rate from their specific calculation that will be monitored by Polar Heart Rate straps.
This group will not partake in the aerobic fitness sessions but will be asked to wear a daily monitoring device every 6 weeks. They will also complete all baseline, 6-month (optional), and 12-month visits.
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
Change in Hippocampal Volume
Magnetic Resonance Imaging (MRI) will be used to measure the structure of the brain. Segmentation algorithms applied to structural MRI images will be used to compute the volume of the hippocampus in particular, which will be evaluated for change over the course of the trial.
Time frame: Baseline & 12 months
Change in Systolic Blood Pressure Responses to Behavioral Tasks
Average systolic blood pressure will be computed during a resting baseline period and during the performance of two behavioral tasks, (1) a Stroop color-word interference task and (2) a multi-source interference task. Mean baseline levels of systolic blood pressure will be subtracted from mean levels averaged across the two tasks to compute response scores, and changes in task-response scores will be evaluated over the course of the trial.
Time frame: Baseline & 12 months
Change in Heart Rate Variability (HRV)
Heart rate variability will be computed from inter-beat intervals derived from electrocardiographic recordings while participants rest in the seated position. Average heart rate variability values from the recording period will be assessed for their change over the trial. Here, we report the natural log-transformed variance of high-frequency (HF) heart rate variability.
Time frame: Baseline & 12 months
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