title: Effects of habitual aerobic exercise on the relationship between intramyocellular or extramyocellular lipid content and arterial stiffness.
abstract: The accumulation of intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) is associated with arterial stiffness in middle-aged and older adults. Habitual aerobic exercise induces the improvement of arterial stiffness with reduction in fat accumulation. However, the relationship between aerobic exercise-induced changes in muscular lipids and arterial stiffness remains unclear. The purpose of this study was to investigate whether habitual aerobic exercise-induced changes in IMCL and EMCL content would lead to an improvement of arterial stiffness. First, in a cross-sectional study, we investigated whether cardiorespiratory fitness level affects the association between IMCL or EMCL content and arterial stiffness in 60 middle-aged and older subjects (61.0±1.3 years). Second, in an intervention study, we examined whether aerobic exercise training-induced changes in IMCL and EMCL content are associated with a reduction in arterial stiffness in 18 middle-aged and older subjects (67.0±1.7 years). In the cross-sectional study, IMCL content was negatively correlated with brachial-ankle pulse wave velocity (baPWV) (r=-0.47, P<0.05), whereas EMCL content was positively correlated with baPWV (r=0.48, P<0.05) in the low-fitness group, but was not correlated in the high-fitness group. Furthermore, 8-week aerobic exercise training in older adults increased IMCL content and reduced EMCL content. The training-induced change in baPWV was negatively correlated with training-induced changes in IMCL but was positively correlated with training-induced changes in EMCL. These findings suggest that aerobic exercise training-induced changes in IMCL and EMCL content may be related to a reduction in arterial stiffness in middle-aged and older adults.
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Hasegawa
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Fujie
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kurihara
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Homma
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sanada
authors.affiliation: Graduate School of Human Development and Environment, Hyogo University, Hyogo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Sports Medicine for Health Promotion, Tokyo Medical University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hamaoka
authors.affiliation: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Iemitsu
mesh_terms: D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008297:Male; D008875:Middle Aged; D032342:Muscle Cells / Q000378:metabolism*; D059289:Vascular Stiffness