TY - JOUR
T1 - Muscle protein synthesis response to exercise training in obese, older men and women
AU - Smith, Gordon I.
AU - Villareal, Dennis T.
AU - Sinacore, David R.
AU - Shah, Krupa
AU - Mittendorfer, Bettina
PY - 2012/7
Y1 - 2012/7
N2 - Introduction: Physical activity and eating are two major physiological muscle growth stimuli. Although muscle protein turnover rates are not different in young and middle-aged men and women, we recently found that the basal rate of muscle protein synthesis is greater and the anabolic response to mixed-meal intake is blunted in 65-to 80-yr-old women compared with men of the same age. Whether older women are also resistant to the anabolic effect of exercise is not known. Methods: We measured the rate of muscle protein synthesis (both during basal, postabsorptive conditions and during mixed-meal intake) before and after 3 months of exercise training in obese, 65-to 80-yr-old men and women. Results: At the beginning of the study (before training) the basal, postabsorptive muscle protein fractional synthesis rate (FSR) was significantly greater in women than in men (0.064 ± 0.006%•h-1 vs 0.039 ± 0.006%•h-1, respectively, P < 0.01), whereas the meal-induced increase in the muscle protein FSR was greater in men than in women (P < 0.05). In men, exercise training approximately doubled the basal muscle protein FSR (P = 0.001) but had no effect on the meal-induced increase in muscle protein FSR (P = 0.78). In women, exercise training increased the muscle protein FSR by ∼40% (P = 0.03) and also had no effect on the meal-induced increase in muscle protein FSR (P = 0.51). Conclusions: These results suggest that there is significant sexual dimorphism not only in the basal, postabsorptive rate of muscle protein synthesis but also in the anabolic response to feeding and exercise training in obese, older adults.
AB - Introduction: Physical activity and eating are two major physiological muscle growth stimuli. Although muscle protein turnover rates are not different in young and middle-aged men and women, we recently found that the basal rate of muscle protein synthesis is greater and the anabolic response to mixed-meal intake is blunted in 65-to 80-yr-old women compared with men of the same age. Whether older women are also resistant to the anabolic effect of exercise is not known. Methods: We measured the rate of muscle protein synthesis (both during basal, postabsorptive conditions and during mixed-meal intake) before and after 3 months of exercise training in obese, 65-to 80-yr-old men and women. Results: At the beginning of the study (before training) the basal, postabsorptive muscle protein fractional synthesis rate (FSR) was significantly greater in women than in men (0.064 ± 0.006%•h-1 vs 0.039 ± 0.006%•h-1, respectively, P < 0.01), whereas the meal-induced increase in the muscle protein FSR was greater in men than in women (P < 0.05). In men, exercise training approximately doubled the basal muscle protein FSR (P = 0.001) but had no effect on the meal-induced increase in muscle protein FSR (P = 0.78). In women, exercise training increased the muscle protein FSR by ∼40% (P = 0.03) and also had no effect on the meal-induced increase in muscle protein FSR (P = 0.51). Conclusions: These results suggest that there is significant sexual dimorphism not only in the basal, postabsorptive rate of muscle protein synthesis but also in the anabolic response to feeding and exercise training in obese, older adults.
KW - Aging
KW - exercise
KW - muscle protein metabolism
KW - nutrition
UR - http://www.scopus.com/inward/record.url?scp=84862765584&partnerID=8YFLogxK
U2 - 10.1249/MSS.0b013e3182496a41
DO - 10.1249/MSS.0b013e3182496a41
M3 - Article
C2 - 22246218
AN - SCOPUS:84862765584
SN - 0195-9131
VL - 44
SP - 1259
EP - 1266
JO - Medicine and Science in Sports and Exercise
JF - Medicine and Science in Sports and Exercise
IS - 7
ER -