Sleep Restriction and Postprandial Lipemia
Condition: Sleep Deprivation; Obesity
MeSH terms: Sleep Deprivation
Study type: Interventional

Summary: 
      Sleep restriction increases overnight and early morning non-esterified fatty acids (NEFA)
      levels, which are correlated with whole-body decreases in insulin sensitivity, consistent
      with the observed impairment of intracellular insulin signaling. Adipose tissue biopsies from
      sleep restricted subjects that are insulin stimulated have reduced phosphorylation of protein
      kinase B (pAKT). This protein is involved in suppression of intracellular lipolysis and NEFA
      release.

      Aerobic exercise has beneficial effects on postprandial lipemia and insulinemia in
      normal-weight and obese individuals. Acute moderate-intensity aerobic exercise (30-90 min)
      performed 12-18 h before an oral fat tolerance test or mixed meal test reduces postprandial
      triglycerides (TG) and insulin concentrations. This response is largely dependent upon the
      exercise-induced energy deficit as the response is abolished when the calories expended
      during exercise are replaced.

      However, it is not known if sleep restriction will interfere with the beneficial effects of
      prior exercise on postprandial lipemia. The aim of this project is to investigate if sleep
      restriction negates the positive effect that exercise has on postprandial lipemia. It is
      hypothesized that sleep restriction will negate the beneficial effects of prior exercise on
      postprandial lipemia. Additionally sleep restriction will result in a worsening of the lipid
      profile compared to no exercise.

      For the proposed study, the investigators will use a repeated measures analysis of variance
      (ANOVA) (4 study conditions (no exercise+ sleep restriction, no exercise+normal sleep,
      exercise+normal sleep, exercise+sleep restriction) x time will be used to analyze changes in
      NEFA and TG concentrations while a one way ANOVA will be used to analyze area under the curve
      of the NEFA and TG concentrations.
    

Detailed description: 
      In the postprandial period, adipocytes respond to the increased insulin levels by suppressing
      intracellular triglycerides (TG) lipolysis and by increasing extracellular lipolysis by
      transporting lipoprotein lipase from intracellular vesicles to the surface of the
      endothelium. This results in decreased free fatty acids (FFA) release into the plasma and
      increased absorption of lipoprotein TGs, particularly those in chylomicrons and VLDLs.

      Sleep restriction increases overnight and early morning non-esterified fatty acids (NEFA)
      levels, which are correlated with whole-body decreases in insulin sensitivity, consistent
      with the observed impairment of intracellular insulin signaling. Adipose tissue biopsies from
      sleep restricted subjects that are insulin stimulated have reduced phosphorylation of protein
      kinase B (pAKT). This protein is involved in suppression of intracellular lipolysis and NEFA
      release. Sleep restriction can also alter whole body substrate metabolism such that there is
      a trend for increased lipid oxidation. Additionally, research examining the effects of
      short-term sleep restriction on circulating lipids have had mixed results. A number of
      studies have found decreases in fasting TG while other studies found no change in plasma TGs
      with sleep restriction.

      Aerobic exercise has beneficial effects on postprandial lipemia and insulinemia in
      normal-weight and obese individuals. Acute moderate-intensity aerobic exercise (30-90 min)
      performed 12-18 h before an oral fat tolerance test or mixed meal test reduces postprandial
      TG and insulin concentrations. This response is largely dependent upon the exercise-induced
      energy deficit as the response is abolished when the calories expended during exercise are
      replaced.

      However, it is not known if sleep restriction will interfere with the beneficial effects of
      prior exercise on postprandial lipemia. The aim of this project is to investigate if sleep
      restriction negates the positive effect that exercise has on postprandial lipemia. It is
      hypothesized that sleep restriction will negate the beneficial effects of prior exercise on
      postprandial lipemia. Additionally sleep restriction will result in a worsening of the lipid
      profile compared to no exercise.

      For the proposed study, the investigators will use a repeated measures ANOVA (4 study
      conditions (no exercise+ sleep restriction, no exercise+normal sleep, exercise+normal sleep,
      exercise+sleep restriction) x time will be used to analyze changes in NEFA and triglyceride
      (TG) concentrations while a one way ANOVA will be used to analyze area under the curve of the
      NEFA and TG concentrations.
    

Intervention name(s): high fat meal
Intervention type(s): Dietary Supplement
Intervention description(s): A high fat meal (milkshake) will be administered on the morning after the intervention of no exercise and no SR the night before.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Subjects will complete all arms of the study in a counterbalanced design
Masking: None (Open Label)
Primary purpose: Prevention