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Influence of exercise on the metabolic profile caused by 28 days of bed rest with energy deficit and amino acid supplementation in healthy men

Citation
Brooks N, Cadena SM, Cloutier GJ, Vega-Lopez S, Roubenoff R & Castaneda-Sceppa C (2014) Influence of exercise on the metabolic profile caused by 28 days of bed rest with energy deficit and amino acid supplementation in healthy men, International Journal of Medical Sciences, 11 (12), pp. 1248-1257.

Abstract
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

StatusPublished
AuthorsBrooks Naomi, Cadena Samuel M, Cloutier Gregory J, Vega-Lopez Sonia, Roubenoff Ronenn, Castaneda-Sceppa Carmen
Publication date12/2014
Publication date online21/09/2014
Date accepted by journal27/08/2014
PublisherIvyspring International Publisher
ISSN 1449-1907
LanguageEnglish

Journal
International Journal of Medical Sciences: Volume 11, Issue 12 (2014)

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