One Week of Bed Rest Leads to Substantial Muscle Atrophy and Induces Whole-Body Insulin Resistance in the Absence of Skeletal Muscle Lipid Accumulation

Diabetes. 2016 Oct;65(10):2862-75. doi: 10.2337/db15-1661. Epub 2016 Jun 29.

Abstract

Short (<10 days) periods of muscle disuse, often necessary for recovery from illness or injury, lead to various negative health consequences. The current study investigated mechanisms underlying disuse-induced insulin resistance, taking into account muscle atrophy. Ten healthy, young males (age: 23 ± 1 years; BMI: 23.0 ± 0.9 kg · m(-2)) were subjected to 1 week of strict bed rest. Prior to and after bed rest, lean body mass (dual-energy X-ray absorptiometry) and quadriceps cross-sectional area (CSA; computed tomography) were assessed, and peak oxygen uptake (VO2peak) and leg strength were determined. Whole-body insulin sensitivity was measured using a hyperinsulinemic-euglycemic clamp. Additionally, muscle biopsies were collected to assess muscle lipid (fraction) content and various markers of mitochondrial and vascular content. Bed rest resulted in 1.4 ± 0.2 kg lean tissue loss and a 3.2 ± 0.9% decline in quadriceps CSA (both P < 0.01). VO2peak and one-repetition maximum declined by 6.4 ± 2.3 (P < 0.05) and 6.9 ± 1.4% (P < 0.01), respectively. Bed rest induced a 29 ± 5% decrease in whole-body insulin sensitivity (P < 0.01). This was accompanied by a decline in muscle oxidative capacity, without alterations in skeletal muscle lipid content or saturation level, markers of oxidative stress, or capillary density. In conclusion, 1 week of bed rest substantially reduces skeletal muscle mass and lowers whole-body insulin sensitivity, without affecting mechanisms implicated in high-fat diet-induced insulin resistance.

Trial registration: ClinicalTrials.gov NCT02109380.

MeSH terms

  • Absorptiometry, Photon
  • Adult
  • Bed Rest / adverse effects*
  • Diet, High-Fat
  • Glucose Clamp Technique
  • Humans
  • Insulin Resistance / physiology*
  • Male
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / pathology*
  • Muscle, Skeletal / physiology*
  • Muscular Atrophy / metabolism
  • Muscular Atrophy / pathology
  • Muscular Atrophy / physiopathology*
  • Quadriceps Muscle / metabolism
  • Quadriceps Muscle / pathology
  • Quadriceps Muscle / physiopathology
  • Young Adult

Associated data

  • ClinicalTrials.gov/NCT02109380