Effects of Exercise Training on Bone Remodeling, Insulin-Like Growth Factors, and Bone Mineral Density in Postmenopausal Women With and Without Hormone Replacement Therapy

Abstract

The purpose of this study was to determine the effects of 12 months of weight bearing and resistance exercise on bone mineral density (BMD) and bone remodeling (bone formation and bone resorption) in 2 groups of postmenopausal women either with or without hormone replacement therapy (HRT). Secondary aims were to characterize the changes in insulin-like growth factors-1 and -2 (IGF-1 and -2) and IGF binding protein 3 (IGFBP3) in response to exercise training. Women who were 3-10 years postmenopausal (aged 40-65 years) were included in the study. Women in the HRT and no HRT groups were randomized into the exercise intervention, resulting in four groups: (1) women not taking HRT, not exercising; (2) those taking HRT, not exercising; (3) those exercising, not taking HRT; and (4) women exercising, taking HRT. The number of subjects per group after 1 year was 27, 21, 25, and 17, respectively. HRT increased BMD at most sites whereas the combination of exercise and HRT produced increases in BMD greater than either treatment alone. Exercise training alone resulted in modest site-specific increases in BMD. Bone remodeling was suppressed in the groups taking HRT regardless of exercise status. The bone remodeling response to exercise training in women not taking HRT was not significantly different from those not exercising. However, the direction of change suggests an elevation in bone remodeling in response to exercise training, a phenomenon usually associated with bone loss. No training-induced differences in IGF-1, IGF-2, IGF-l:IGF-2 (IGF-1 : IGF-2), and IGFBP3 were detected.

Effects of Different Intensity Resistance Exercise Programs on Bone Turnover Markers, Osteoprotegerin and Receptor Activator of Nuclear Factor Kappa Β Ligand in Post-Menopausal Women

“…57 On the ot her hand, Mil li ken et al fo und that exer ci sers, who per for med both we ight-be a -ring ae ro bic tra i ning and re sis tan ce tra i ning, showed a trend to ward lar ger po si ti ve chan ges in both bo ne for ma ti on and re sorp ti on over 12 months vs con trols. 13 In our study, the sig ni fi cant in cre a se in OC in HIG can be ac cep ted as a sign of po si ti ve ef fects of high-in ten sity re sis tan ce trai ning on bo ne for ma ti on. Our fin ding is in pa rallel with ot her stu di es that fo und in cre a ses in OC le vels as a re sult of strength tra i ning.…”

“…Our fin ding is in pa rallel with ot her stu di es that fo und in cre a ses in OC le vels as a re sult of strength tra i ning. 13,41,58,59 Vincent et al, Fu ji mu ra et al, and Men kes et al fo und in cre a ses in ALP ac ti vi ti es of the ath le tes. 41,58,59 Ho we ver, we co uld not ob ser ve any chan ges in BAP ac ti vi ti es in any of our gro ups.…”

“…[7][8][9][10][11] Stu di es of the physi o lo gi cal res pon se of the se markers in he althy sub jects du ring exer ci se ha ve be en li mi ted, and the exis ting stu di es ha ve con tra dic tory re sults. Ha to ri et al de ter mi ned that BMD in cre a ses wit ho ut a chan ge in OC le vels with high-in ten sity wal king prog rams; 12 Mil li ken et al fo und a trend to wards in cre ment in OC with exer ci se; 13 and Ethe ring ton et al de ter mi ned re duc ti ons in OC and ALP with we ight-be a ring exer ci se.…”

Changes in Endothelial Function after Acute Resistance Exercise Using Free Weights

“…While the effects of resistance exercise are well known in terms of muscle strength and endurance [1,2], prevention of osteoporosis [3], and sarcopenia [4], the effects on the vasculature are less clear. Previous work that has evaluated changes in endothelial function after resistance exercise has demonstrated positive effects [5].…”

The Effects of a Uniformly Weighted Exercise Suit on Biomarkers of Bone Turnover in Response to Aerobic Exercise in Postmenopausal Women With Low Bone Density

“…However, weighted aerobic exercise, utilizing load carriage systems (LCS), increases the gravitational forces impacting the bone creating a higher osteogenic stimulus than standard aerobic exercise. LCS also allow for the forces to be delivered in a more gradual manner, rather than at the higher rate produced by resistance training (Klentrou, Slack, Roy, & Ladouceur, 2007;Kohrt, Ehsani, & Birge, 1997;Milliken et al, 2003;Snow, Shaw, Winters, & Witzke, 2000;Tosun, Bolukbasi, Cingi, Beyazova, & Unlu, 2006). Currently, there are several LCS designs (backpacks, front packs, double packs, weighted vests, hand and ankle weights, etc.…”