Association between Exercise Training-induced Irisin Secretion and Reduction of Visceral Fat
【Supercategory：7. DESCENTE SPORTS SCIENCE Subcategory：7.35 Vol.35】
One of the myokine, irisin is secreted from muscles. Irisin induces increasing thermogenesis via upregulation of uncoupling protein-1 mRNA expression in white adipose tissue. However, it is unclear that the effect of exercise training on circulating irisin levels is associated with alteration of body fat in healthy young and older adults.
PURPOSE: This study aimed to clarify the association between aerobic exercise training effects of circulating irisin levels and body fat in young and older adults.
METHODS: Twenty-five healthy young subjects (age 22 ± 4 years, male: n = 16; female: n = 9) and 30 healthy old subjects (age 67 ± 7 years, male: n = 12; female: n = 18) were participated in the present study. Each subject was randomly divided into two groups: the training group (young: n = 15, old: n = 14) and the control group. Subjects in the training group completed 8-week of aerobic exercise training (60-70% peak oxygen uptake [VO₂peak] for 45 min, 3 days/week). Before and after the intervention, we evaluated plasma irisin concentrations, VO₂peak as an index of cardiorespiratory fitness, and cross-sectional area of abdominal visceral and subcutaneous adipose tissue using by magnetic resonance imaging (MRI)．
RESULTS: In the training groups of young and older adults, VO₂peak was significantly increased after the intervention (P<0.05), and serum irisin level was significantly increased in the older training group after the intervention (P<0.01) , but not change in the young training group. Additionally, there was a correlation between the training effects of serum irisin levels and abdominal visceral area (r = -0.54, P<0.05) in the older. However, there were no significant associations between the training effects of serum irisin levels and abdominal subctaneous area in the older.
CONCLUSION: These results suggest that the increased in serum irisin levels may be associated with exercise training-induced alternation of abdominal visceral area in older adults.
DESCENTE SPORTS SCIENCE Vol.35/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
PURPOSE: This study aimed to clarify the association between aerobic exercise training effects of circulating irisin levels and body fat in young and older adults.
METHODS: Twenty-five healthy young subjects (age 22 ± 4 years, male: n = 16; female: n = 9) and 30 healthy old subjects (age 67 ± 7 years, male: n = 12; female: n = 18) were participated in the present study. Each subject was randomly divided into two groups: the training group (young: n = 15, old: n = 14) and the control group. Subjects in the training group completed 8-week of aerobic exercise training (60-70% peak oxygen uptake [VO₂peak] for 45 min, 3 days/week). Before and after the intervention, we evaluated plasma irisin concentrations, VO₂peak as an index of cardiorespiratory fitness, and cross-sectional area of abdominal visceral and subcutaneous adipose tissue using by magnetic resonance imaging (MRI)．
RESULTS: In the training groups of young and older adults, VO₂peak was significantly increased after the intervention (P<0.05), and serum irisin level was significantly increased in the older training group after the intervention (P<0.01) , but not change in the young training group. Additionally, there was a correlation between the training effects of serum irisin levels and abdominal visceral area (r = -0.54, P<0.05) in the older. However, there were no significant associations between the training effects of serum irisin levels and abdominal subctaneous area in the older.
CONCLUSION: These results suggest that the increased in serum irisin levels may be associated with exercise training-induced alternation of abdominal visceral area in older adults.
DESCENTE SPORTS SCIENCE Vol.35/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
| Researcher | Motoyuki Iemitsu, Koji Sato, Toshiyuki Kurihara, Satoshi Fujita, Takafumi Hamaoka |
|---|---|
| University or institution | Ritsumeikan University |
Keywords
irisin, thermogenesis, exercise training, body fat, aerobic exercise, 60-70% peak oxygen uptake [VO₂peak], serum irisin, abdominal visceral