20 February 2018
Int J Med Sci 2014; 11(12):1248-1257. doi:10.7150/ijms.9694
Influence of Exercise on the Metabolic Profile Caused by 28 days of Bed Rest with Energy Deficit and Amino Acid Supplementation in Healthy Men
1. Health & Exercise Sciences, University of Stirling, Stirling, Scotland UK
Objective Muscle loss and metabolic changes occur with disuse [i.e. bed rest (BR)]. We hypothesized that BR would lead to a metabolically unhealthy profile defined by: increased circulating tumor necrosis factor (TNF)-α, decreased circulating insulin-like-growth-factor (IGF)-1, decreased HDL-cholesterol, and decreased muscle density (MD; measured by mid-thigh computerized tomography).
Methods We investigated the metabolic profile after 28 days of BR with 8±6% energy deficit in male individuals (30-55 years) randomized to resistance exercise with amino acid supplementation (RT, n=24) or amino acid supplementation alone (EAA, n=7). Upper and lower body exercises were performed in the horizontal position. Blood samples were taken at baseline, after 28 days of BR and 14 days of recovery.
Results We found a shift toward a metabolically unfavourable profile after BR [compared to baseline (BLN)] in both groups as shown by decreased HDL-cholesterol levels (EAA: BLN: 39±4 vs. BR: 32±2 mg/dL, RT: BLN: 39±1 vs. BR: 32±1 mg/dL; p<0.001) and Low MD (EAA: BLN: 27±4 vs. BR: 22±3 cm2, RT: BLN: 28±2 vs. BR: 23±2 cm2; p<0.001). A healthier metabolic profile was maintained with exercise, including NormalMD (EAA: BLN: 124±6 vs. BR: 110±5 cm2, RT: BLN: 132±3 vs. BR: 131±4 cm2; p<0.001, time-by-group); although, exercise did not completely alleviate the unfavourable metabolic changes seen with BR. Interestingly, both groups had increased plasma IGF-1 levels (EAA: BLN:168±22 vs. BR 213±20 ng/mL, RT: BLN:180±10 vs. BR: 219±13 ng/mL; p<0.001) and neither group showed TNFα changes (p>0.05).
Conclusions We conclude that RT can be incorporated to potentially offset the metabolic complications of BR.
Keywords: resistance training, essential amino acids, energy deficit, metabolic profile
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How to cite this article:
Brooks NE, Cadena SM, Cloutier G, Vega-López S, Roubenoff R, Castaneda-Sceppa C. Influence of Exercise on the Metabolic Profile Caused by 28 days of Bed Rest with Energy Deficit and Amino Acid Supplementation in Healthy Men. Int J Med Sci 2014; 11(12):1248-1257. doi:10.7150/ijms.9694. Available from http://www.medsci.org/v11p1248.htm