title: Influence of regular exercise on age-related changes in arterial elasticity: mechanistic insights from wall compositions in rat aorta.
abstract: Arterial stiffness increases with age in healthy sedentary adults. We previously reported that the age-related increases in arterial stiffness are absent or attenuated in regularly exercising adults. However, the mechanism underlying this training effect is unknown. One possibility is that regular exercise minimizes age-related changes in the arterial wall composition of elastin and collagen. To gain insight into this issue, we studied four groups of rats (N = 23): young (42-46 wks) and old (80-84 wks), sedentary and exercise-trained. The exercise group swam 1 hr.d-1, 6 d.wk-1 for 17-21 weeks. There was no significant difference in the incremental elastic modulus between young sedentary and exercise-trained rats. The elastic moduli of the old exercise-trained rats were 31% lower than in the old sedentary controls. As such, the magnitude of age-related increase in the elastic modulus was smaller in the exercise-trained (110%) vs. the sedentary group (151%) (p < 0.05). In both activity groups, elastin content was lower and collagen content was higher in old vs. young rats (p < 0.05). However, there were no significant differences between the two activity groups. These results are not consistent with the hypothesis that regular physical exercise minimizes age-related compositional changes in the arterial wall and attenuates the age-related increase in arterial stiffness.
authors.affiliation: Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba-shi, Ibaraki 305, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Nosaka
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Izumi
authors.initials: I
authors.lastname: Watanabe
authors.forename: Masaaki
authors.initials: M
authors.lastname: Sato
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology*; D004548:Elasticity; D008297:Male; D010805:Physical Conditioning, Animal; D051381:Rats; D011921:Rats, Inbred WKY; D013718:Tensile Strength