Individual Differences in Diabetes Risk: Role of Slow WaveSleep

Inclusion Criteria: * healthy volunteers age 18-20 with a BMI \< 27kg/m2 in women and \< 28 kg/m2 in men with normal findings on clinical examination, routine laboratory tests and EKG * only subjects who have regular life styles (no shift work, no travel across time zone during the previous 4 weeks) * habitual bedtimes between 7.0-8.5 hours/night * do not take medications will be recruited Exclusion Criteria: * women taking hormonal contraceptive therapy and pregnant women will be excluded * individuals with a history of psychiatric, endocrine, cardiac or sleep disorders will be excluded * other exclusion criteria will be: tobacco use, habitual alcohol use of more than 1 drink per day, excessive caffeine intake of more than 300 mg per day