School of Kinesiology, The University of Michigan, Ann Arbor, MI 48109, USA.
School of Physical Education, Henan University Kaifeng, 475000 Henan, China.
Nutrients. 2019 Jun 30;11(7):1494. doi: 10.3390/nu11071494.
Type 2 diabetes increases bone fracture risk in postmenopausal women. Usual treatment with anti-resorptive bisphosphonate drugs has some undesirable side effects, which justified our interest in the osteogenic potential of nutrition and exercise. Since meal eating reduces bone resorption, downhill locomotion increases mechanical stress, and brief osteogenic responsiveness to mechanical stress is followed by several hours of refractoriness, we designed a study where 40-min of mechanical stress was manipulated by treadmill walking uphill or downhill. Exercise preceded or followed two daily meals by one hour, and the meals and exercise bouts were 7 hours apart. Fifteen subjects each performed two of five trials: No exercise (SED), uphill exercise before (UBM) or after meals (UAM), and downhill exercise before (DBM) or after meals (DAM). Relative to SED trial, osteogenic response, defined as the ratio of osteogenic C-terminal propeptide of type I collagen (CICP) over bone-resorptive C-terminal telopeptide of type-I collagen (CTX) markers, increased in exercise-after-meal trials, but not in exercise-before-meal trials. CICP/CTX response rose significantly after the first exercise-after-meal bout in DAM, and after the second one in UAM, due to a greater CICP rise, and not a decline in CTX. Post-meal exercise, but not the pre-meal exercise, also significantly lowered serum insulin response and homeostatic model (HOMA-IR) assessment of insulin resistance.
2 型糖尿病增加绝经后妇女的骨折风险。通常使用抗吸收双膦酸盐药物治疗，但这些药物有一些不良的副作用，这促使我们对营养和运动的成骨潜力产生了兴趣。由于进餐可减少骨吸收，下坡运动增加机械应力，并且机械应力的短暂成骨反应之后是几个小时的不应期，因此我们设计了一项研究，通过跑步机上下坡运动来控制 40 分钟的机械应力。运动前或后 1 小时各进两餐，两餐之间相隔 7 小时。15 名受试者每人进行 5 次试验中的两次：不运动（SED）、运动前进餐后（UBM）或运动后进餐后（UAM）、运动前下餐后（DBM）或运动后下餐后（DAM）。与 SED 试验相比，成骨反应（定义为 I 型胶原 C 端肽（CICP）与 I 型胶原 C 端肽（CTX）的骨吸收标志物的比值）在餐后运动试验中增加，但在餐前运动试验中没有增加。由于 CICP 升高而不是 CTX 降低，DAM 中的第一次餐后运动后和 UAM 中的第二次餐后运动后，CICP/CTX 反应显著升高。餐后运动而不是餐前运动还显著降低了血清胰岛素反应和胰岛素抵抗的稳态模型（HOMA-IR）评估。
