Individual Differences in Diabetes Risk: Role of Sleep Disturbances

Inclusion Criteria: * Healthy men and women with low Slow Wave Sleep Activity (SWA) or high SWA with the gender distribution in each group matching the gender distribution of active duty Army personnel (85% men; 15% women) based on the following inclusion criteria: * age 18 to 29 years, * normal weight or modestly overweight (BMI ≤ 27 kg/m2 for women, BMI ≤ 28 kg/m2 for men), * normal findings on clinical examination, normal routine laboratory tests results, normal EKG, no history of psychiatric, endocrine, cardiac or sleep disorders. * Only subjects who have regular life styles (no shift work, no travel across time zone during the past 4 weeks), habitual bedtimes between 7.0-8.5 hours, and do not take medications will be recruited. * An overnight polysomnography will be performed to rule out sleep-disordered breathing (apnea-hypopnea index \> 5/hour) and periodic limb movement disorder (PLM arousal index \>1/hour). * Women taking hormonal contraceptive therapy and pregnant women will be excluded. In women, all studies will be initiated in the early follicular phase. Exclusion Criteria: * Tobacco use. * Habitual alcohol use of more than 2 1 drink per day. * Excessive caffeine intake of more than 300 mg per day and individuals with a metal implant or another metal object in their body. We estimate that we will need to recruit at least 60-70 individuals to obtain two gender-matched groups of 16 individuals with either low or high SWA.