This study is designed to determine the impact of extending sleep duration on glucose metabolism in people with obesity. Half of the participants will be instructed to increase their time-in-bed in order to achieve \>7h sleep/night (sleep extension; n=15) while the other half will be be instructed to maintain their current sleep habits (n=15).
Restricting sleep is known to be detrimental to glucose metabolism in healthy adults. Obesity is a condition associated with both lower sleep duration and poor glucose tolerance. Therefore, increasing sleep duration is a potentially novel therapeutic strategy for improving glucose metabolism in this population. The investigators will assess this by determining insulin sensitivity during a hyperinsulinemic-euglycemic clamp before and after a sleep intervention in both the control and sleep extension groups.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
31
Extend time-in-bed by one hour
Washington University School of Medicine
St Louis, Missouri, United States
Insulin Sensitivity
Whole-body insulin sensitivity calculated as the insulin stimulated rate of glucose disposal per kilogram of fat-free body mass (µmol/kgFFM/min) during a hyperinsulinemic-euglycemic clamp.
Time frame: Change from baseline testing after 4-6 weeks of intervention
Hepatic Insulin Sensitivity Index
Calculated as the inverse of the product of plasma insulin concentration and endogenous glucose rate of appearance (Ra)/kgFFM during the basal period of the clamp procedure. Higher values indicate greater insulin sensitivity.
Time frame: Change from baseline testing after 4-6 weeks of intervention
Adipose Tissue Insulin Sensitivity Index
Calculated as the reciprocal of the product of palmitate Ra/kgFFM and plasma insulin concentration during basal conditions. Higher values indicate greater insulin sensitivity.
Time frame: Change from baseline testing after 4-6 weeks of intervention
Homeostatic Model Assessment of Insulin Resistance
The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated by dividing the product of the plasma concentrations of insulin (in µU/mL) and glucose (in mmol/L) by 22.5. Higher values indicate greater insulin resistance.
Time frame: Change from baseline testing after 4-6 weeks of intervention
24 Hour Glucose Area Under the Concentration Curve
Plasma metabolite concentrations will be evaluated over a 24 hour period
Time frame: Change from baseline testing after 4-6 weeks of intervention
24 Hour Insulin Area Under the Concentration Curve
Plasma insulin concentrations evaluated over a 24 hour period
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Time frame: Change from baseline testing after 4-6 weeks of intervention
24 Hour Non-esterified Fatty Acids Area Under the Concentration Curve
Plasma metabolite concentrations will be evaluated over a 24 hour period
Time frame: Change from baseline testing after 4-6 weeks of intervention
Body Mass
Measured using a body weight scale
Time frame: Change from baseline testing after 4-6 weeks of intervention
Fat-free Mass
Body composition assessed using dual-energy x-ray absorptiometry (DXA)
Time frame: Change from baseline testing after 4-6 weeks of intervention
Body Fat
Body composition assessed using dual-energy x-ray absorptiometry (DXA)
Time frame: Change from baseline testing after 4-6 weeks of intervention
Liver Fat
Proton-density fat fraction of the whole liver assessed by using magnetic resonance imaging (MRI)
Time frame: Change from baseline testing after 4-6 weeks of intervention
Fasting Glucose
Plasma glucose measured after an overnight fast
Time frame: Change from baseline testing after 4-6 weeks of intervention
Daily Time in Bed
Assessed by using actigraphy over 7 days
Time frame: Change from baseline testing after 4-6 weeks of intervention
Daily Total Sleep Time
Assessed by using actigraphy over 7 days
Time frame: Change from baseline testing after 4-6 weeks of intervention
Stage N1 Sleep Time
Assessed by using inpatient polysomnography
Time frame: Change from baseline testing after 4-6 weeks of intervention
Stage N2 Sleep Time
Assessed by using inpatient polysomnography
Time frame: Change from baseline testing after 4-6 weeks of intervention
Stage N3 Sleep Time
Assessed by using inpatient polysomnography
Time frame: Change from baseline testing after 4-6 weeks of intervention
Rapid Eye Movement (REM) Sleep Time
Assessed by using inpatient polysomnography
Time frame: Change from baseline testing after 4-6 weeks of intervention