Graded intensity aerobic exercise to improve cerebrovascular function and performance in older Veterans: Protocol for a randomized controlled trial

Abstract: Background: Growing health care challenges resulting from a rapidly expanding aging population necessitate examining effective rehabilitation techniques that mitigate age-related comorbidity and improve quality of life. To date, exercise is one of a few proven interventions known to attenuate age-related declines in cognitive and sensorimotor functions critical to sustained independence. Objective: This work aims to implement a multimodal imaging approach to better understand the mechanistic underpinnings of the beneficial exercise-induced adaptations to sedentary older adults' brains and behaviors. Due to the complex cerebral and vascular dynamics that encompass neuroplastic change with aging and exercise, we propose an imaging protocol that will model exercise-induced changes to cerebral perfusion, cerebral vascular reactivity (CVR), and cognitive and sensorimotor task-dependent functional magnetic resonance imaging (fMRI) after prescribed exercise. Methods: Sedentary older adults (aged 65-80 years) were randomly assigned to either a 12-week aerobic-based interval-based cycling intervention or a 12-week balance and stretching intervention. Assessments of cardiovascular fitness used the YMCA submaximal VO(2) test, basal cerebral perfusion using arterial spin labeling (ASL), CVR using hypercapnic fMRI, and cortical activation using fMRI during verbal fluency and motor tapping tasks. A battery of cognitive-executive and motor function tasks outside the scanning environment will be performed before and after the interventions. Results: Our studies and others show that improved cardiovascular fitness in older adults results in improved outcomes related to physical and cognitive health as well as quality of life. A consistent but unexplained finding in many of these studies is a change in cortical activation patterns during task-based fMRI, which corresponds with improved task performance (cognitive-executive and motor). We hypothesize that the 12-week aerobic exercise intervention will increase basal perfusion and improve CVR through a greater magnitude of reactivity in brain areas susceptible to neural and vascular decline (inferior frontal and motor cortices) in previously sedentary older adults. To differentiate between neural and vascular adaptations in these regions, we will map changes in basal perfusion and CVR over the inferior frontal and the motor cortices-regions we have previously shown to be beneficially altered during fMRI BOLD (blood oxygen level dependent), such as verbal fluency and motor tapping, through improved cardiovascular fitness. Conclusions: Exercise is one of the most impactful interventions for improving physical and cognitive health in aging. This study aims to better understand the mechanistic underpinnings of improved health and function of the cerebrovascular system. If our hypothesis of improved perfusion and cerebrovascular reactivity following a 12-week aerobic exercise intervention is supported, it would add critically important insights into the potential of exercise to improve brain health in aging and could inform exercise prescription for older adults at risk for neurodegenerative disease brought on by cerebrovascular dysfunction.

Read the full article
Report a problem with this article

Related articles

  • More for Researchers

    Qualitative analysis of the lived experience of reproductive and pediatric health care in the military health care system

    Abstract: Introduction: Persistent inequities exist in obstetric and neonatal outcomes in military families despite universal health care coverage. Though the exact underlying cause has not been identified, social determinants of health may uniquely impact military families. The purpose of this study was to qualitatively investigate the potential impact of social determinants of health and the lived experiences of military individuals seeking maternity care in the Military Health System. Materials and methods: This was an Institutional Review Board-approved protocol. Nine providers conducted 31 semi-structured interviews with individuals who delivered within the last 5 years in the direct or purchased care market. Participants were recruited through social media blasts and clinic flyers with both maximum variation and homogenous sampling to ensure participation of diverse individuals. Data were coded and themes were identified using inductive qualitative research methods. Results: Three main themes were identified: Requirements of Military Life (with subthemes of pregnancy notification and privacy during care, role of pregnancy instructions and policies, and role of command support), Sociocultural Aspects of the Military Experience (with subthemes of pregnancy as a burden on colleagues and a career detractor, postpartum adjustment, balancing personal and professional requirements, pregnancy timing and parenting challenges, and importance of friendship and camaraderie in pregnancy), and Navigating the Healthcare Experience (including subthemes of transfer between military and civilian care and TRICARE challenges, perception of military care as inferior to civilian, and remote duty stations and international care). Conclusions: The unique stressors of military life act synergistically with the existing health care challenges, presenting opportunities for improvements in care. Such opportunities may include increased consistency of policies across services and commands. Increased access to group prenatal care and support groups, and increased assistance with navigating the health care system to improve care transitions were frequently requested changes by participants.

    Physical Health Peer reviewed