title: Cardiorespiratory fitness modifies the relationship between myocardial function and cerebral blood flow in older adults.
abstract: A growing body of evidence indicates that cardiorespiratory fitness attenuates some age-related cerebral declines. However, little is known about the role that myocardial function plays in this relationship. Brain regions with high resting metabolic rates, such as the default mode network (DMN), may be especially vulnerable to age-related declines in myocardial functions affecting cerebral blood flow (CBF). This study explored the relationship between a measure of myocardial mechanics, global longitudinal strain (GLS), and CBF to the DMN. In addition, we explored how cardiorespiratory affects this relationship. Participants were 30 older adults between the ages of 59 and 69 (mean age=63.73years, SD=2.8). Results indicated that superior cardiorespiratory fitness and myocardial mechanics were positively associated with DMN CBF. Moreover, results of a mediation analysis revealed that the relationship between GLS and DMN CBF was accounted for by individual differences in fitness. Findings suggest that benefits of healthy heart function to brain function are modified by fitness.
authors.affiliation: Division of Physical Therapy, Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA. Electronic address: nathan.johnson@uky.edu.
authors.forename: Nathan F
authors.initials: NF
authors.lastname: Johnson
authors.affiliation: Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA; Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY 40536, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA. Electronic address: brian.gold@uky.edu.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Gold
authors.affiliation: Gill Heart Institute, University of Kentucky, Lexington, KY 40536, USA. Electronic address: alison.bailey@uky.edu.
authors.forename: Alison L
authors.initials: AL
authors.lastname: Bailey
authors.affiliation: Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40536, USA; Clinical Services Core, University of Kentucky, Lexington, KY 40536, USA. Electronic address: jlclas0@email.uky.edu.
authors.forename: Jody L
authors.initials: JL
authors.lastname: Clasey
authors.affiliation: Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA. Electronic address: jghakun@uky.edu.
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Hakun
authors.affiliation: Gill Heart Institute, University of Kentucky, Lexington, KY 40536, USA. Electronic address: matt.white@uky.edu.
authors.forename: Matthew
authors.initials: M
authors.lastname: White
authors.affiliation: Clinical Services Core, University of Kentucky, Lexington, KY 40536, USA; College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA. Electronic address: delong2@uky.edu.
authors.forename: Doug E
authors.initials: DE
authors.lastname: Long
authors.affiliation: Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA; Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY 40536, USA. Electronic address: dkpowe00@mri.uky.edu.
authors.forename: David K
authors.initials: DK
authors.lastname: Powell
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology*; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: Aging; Arterial spin labeling; Cardiorespiratory fitness; Default mode network; Global longitudinal strain