Sleep Loss and Glucose Metabolism in People With Family History of Type 2 Diabetes.

• First and second phase insulin secretion [ Time Frame: at the end of each bedtime intervention ] [ Designated as safety issue: No ]
• Endogenous glucose production [ Time Frame: at the end of each bedtime intervention ] [ Designated as safety issue: No ]
• Glycerol turnover and free fatty acid concentrations [ Time Frame: at the end of each bedtime intervention ] [ Designated as safety issue: No ]

The use of sugar and starch-like foods for energy (carbohydrate metabolism) changes when people sleep. However, it is still not known if differences in the amount of nighttime sleep have an effect on the carbohydrate metabolism of people who have a relative with type 2 diabetes (parent, sibling, or grandparent). This study is being done to test the hypothesis that the carbohydrate metabolism of people who have a history of type 2 diabetes in their family will be different after they have slept short hours for 10 days in comparison to when they have slept longer hours for 10 days.

Study participants will complete two 10-day inpatient stays in the sleep laboratory of the University of Chicago Clinical Resource Center scheduled at least 4 weeks apart. Bedtime duration will be set at 5 hours per night during one of these stays and 8.5 hours per night during the other. No daytime naps will be allowed. Study participants will be served regular daily meals including breakfast, lunch, dinner, and a bedtime snack. On weekdays all participants will engage in simulated "office work" while in the sleep laboratory. During the rest of the time participants will maintain their usual indoor and outdoor activities as much as possible within the limits of the University of Chicago campus. During the last two days of each inpatient stay in the laboratory, participants will undergo two different tests. The first test will determine how much insulin does their body produce in response to an intravenous glucose infusion lasting several hours. The second test will determine how effective is the action of the sugar-processing hormone, insulin, in their body when it is infused intravenously together with glucose over a period of several hours.

• Sleep
• Sleep Deprivation
• Insulin Resistance
• Type 2 Diabetes

• Other: 5-hour bedtime
  10 days with sleep restricted only to a 5-hour bedtime period at night
• Other: 8.5-hour bedtimes
  10 days with sleep allowed only during a 8.5-hour period at night

• Experimental: 5-hour bedtime
  Intervention: Other: 5-hour bedtime
• Experimental: 8.5-hour bedtime
  Intervention: Other: 8.5-hour bedtimes

Inclusion Criteria:

• regular sleep habits
• BMI 20 to 27 kg/m2
• at least one parent, sibling or grandparent with type 2 diabetes
• no regular exercise habits

Exclusion Criteria:

• active smoker
• night or shift work
• have highly variable sleep habits
• have a hormonal disorder
• have a sleep disorder
• have an active medical problem
• women only: use of birth control pills
• women only: irregular menstrual periods or pregnancy
• use of medications/compounds that can disrupt sleep