title: Endurance training-induced increase in circulating irisin levels is associated with reduction of abdominal visceral fat in middle-aged and older adults.
abstract: To elucidate the effects of endurance training on circulating irisin levels in young and middle-aged/older adults, and to determine the association between endurance training-induced alteration of irisin and reduction in body fat. Twenty-five healthy young (age 21 ± 1 years; 16 men, 9 women) and 28 healthy middle-aged/older adults (age 67 ± 8 years; 12 men, 16 women) participated in the study. Each age cohort was divided into two groups: the endurance-training group (14 young, 14 middle-aged/older) and the control group. Subjects in the training groups completed an 8-week endurance-training program (cycling at 60-70% peak oxygen uptake [V̇O2peak] for 45 min, 3 days/week). Before and after the intervention, we evaluated serum irisin level, V̇O2peak, and body composition. The increase in V̇O2peak in the young and middle-aged/older training groups after the intervention period was significantly greater than those in the young and middle-aged/older control groups (P < 0.05). Serum irisin level was significantly increased in the middle-aged/older training group after the intervention period (P < 0.01), but not in the young training group. Furthermore, in the middle-aged/older training group, the endurance training-induced reduction in visceral adipose tissue area was negatively correlated with the change in serum irisin level (r = -0.54, P < 0.05). These results suggest a possible role for secreted irisin in the exercise-induced alteration of abdominal visceral fat in middle-aged and older adults.
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan; Japan Society for the Promotion of Science, Tokyo, Japan.
authors: Eri
authors: E
authors: Miyamoto-Mikami
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Koji
authors: K
authors: Sato
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Toshiyuki
authors: T
authors: Kurihara
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Natsuki
authors: N
authors: Hasegawa
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Shumpei
authors: S
authors: Fujie
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Satoshi
authors: S
authors: Fujita
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Kiyoshi
authors: K
authors: Sanada
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Takafumi
authors: T
authors: Hamaoka
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Izumi
authors: I
authors: Tabata
authors: Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
authors: Motoyuki
authors: M
authors: Iemitsu
mesh_terms: D000368:Aged; D001823:Body Composition; D001835:Body Weight; D016022:Case-Control Studies; D005260:Female; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D050152:Intra-Abdominal Fat / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance; D055815:Young Adult
chemical_list: C577593:FNDC5 protein, human; D005353:Fibronectins