(P15-009-24) Sleep Extension Does Not Increase Insulin Sensitivity in People With Obesity Who Are Habitual Short-Sleepers

Objectives: To test the hypothesis that extending sleep duration improves insulin sensitivity in people with obesity who are short-sleepers ( < 7 h/night) and have abnormal glucose metabolism, defined as having impaired fasting glucose, impaired glucose tolerance, or insulin resistance (homeostatic model assessment for insulin resistance [HOMA-IR] score ≥2.0).

Methods: Twenty-five people with obesity, abnormal glucose metabolism and routinely sleep < 7 h/night were randomly assigned to either habitual sleep (CON; n=14) or sleep extension (SE; n=11) for 4-6 weeks; 9 of the 14 participants who completed the CON intervention also completed the SE intervention, so the data from 14 CON (age: 41±3 y; BMI: 33±1 kg/m²; 10 females) and 20 SE (age: 40±3 y; BMI: 35±1 kg/m²; 14 females) interventions are reported here. SE participants were instructed on proper sleep hygiene and daily sleep was extended by adjusting bed time or wake time to increase time-in-bed. Sleep was monitored by using actigraphy and whole-body insulin sensitivity was assessed as insulin-stimulated glucose disposal, determined by using a hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotope glucose tracer infusion.

Results: Time-in-bed and total sleep time increased by 1.2±0.2 h/night (P < 0.001) and 0.9±0.1 h/night (P < 0.001), respectively, in the SE group, but did not change in the CON group (0.32±0.21 h/night and 0.10±0.12 h/night, respectively, P >0.05) (P < 0.05 for differences between CON and SE groups). Compared with the CON group, SE did not affect body weight (SE: -0.3±0.3% vs. CON: -0.6±0.7% change) or HOMA-IR (SE: +6.1±4.8% vs. CON: -3.5±9.5% change) (all P >0.05). Whole-body insulin sensitivity (glucose disposal rate during the clamp procedure) after the intervention in the CON and SE groups (426±57 and 430±48 nmol/kg fat-free mass/min/per µU/mL insulin, respectively) were not different than the values before the intervention (452±59 and 422±56 nmol/kg fat-free mass/min/ per µU/mL insulin, respectively) (P=0.26 for CON vs SE in the change in insulin sensitivity).

Conclusions: The results from this study demonstrate that increasing time-in-bed and total sleep time by ~1 h in people with obesity who are short-sleepers does not improve insulin sensitivity.

Funding Sources: National Institutes of Health