Effects of Energy Restriction and Exercise on Bone Mineral Density during Lactation
Medicine and Science in Sports and Exercise, 07/25/2012
Colleran HL et al. – The results suggest that moderate energy restriction combined with resistance training (RT) promotes weight loss with no adverse effects on Bone Mineral Density (BMD) during lactation.Methods
- At 4 wk postpartum, participants were randomized to either a 16–wk intervention (diet restricted by 500 kcal and RT 3 d•wk–1) group (IG = 14) or minimal care group (CG = 13).
- Measurements included BMD by DXA, three 24–h dietary recalls, and hormones.
- Repeated–measures ANOVA was used to test for group differences over time.
- Energy intake decreased more in IG (613 ± 521 kcal) than CG (171 ± 435 kcal) (P = 0.03). IG lost more weight (5.8 ± 3.5 kg vs CG = 1.6 ± 5.4 kg, P = 0.02).
- BMD decreased over time, P < 0.01, with no group differences in lumbar spine (IG = 3.4% ± 2.5%, CG = 3.7% ± 3.3%) or hip (IG and CG = 3.1 ± 1.8%).
- Prolactin and estradiol decreased over time in both groups, P < 0.01.
- Basal growth hormone remained stable; however, there was a significant increase in growth hormone response to exercise in IG.