Sleep and Metabolism

Inclusion Criteria: * Between 18 and 40 years of age * Drug free * Established disease-free status Exclusion Criteria: 1. Dietary restrictions Participants must not have dietary restrictions that could systematically bias their macronutrient intake. The following will exclude participants from enrolling in the study based on their diet: * Participants who choose not to or cannot consume dairy products (milk, yogurt, cheese, ice cream) 2. Body Composition A body mass index (BMI) of 18.5\< \[BMI\] \< 25 kg/m2 and a waist circumference \<94/80cm. 3. Psychiatric/psychological suitability Each participant will undergo a structured interview (Mini International Neuropsychiatric Interview) with a qualified OHSU physician. This physician will supervise the administration and scoring of a Beck Depression Inventory II (BDI-II) questionnaire for each potential participant. The following will exclude individuals from participating based on their psychiatric or psychological evaluation: * Individuals with evidence of psychopathology on the BDI-II, or in a structured clinical interview with the physician * A history of severe psychiatric illnesses * Alcoholism * Drug dependency * Major depression * Manic depressive illness * Schizophrenic disorders * Panic disorder * Generalized anxiety disorder * Post-traumatic stress disorder * Agoraphobia * Claustrophobia * Paranoid personality disorder * Schizoid personality disorder * Schizotypal personality disorder * Borderline personality disorder * Antisocial personality disorder. * History of using antidepressant medication * History of using neuroleptic medication * History of using tranquilizers 4. Drug/alcohol use Volunteers must be drug-free (including caffeine, nicotine, alcohol and herbal medications) for the entire duration of the outpatient and in-laboratory study period, with no history of drug or alcohol dependency. All participants must be: * Current non-smokers, and are required to have a history of less than 5 'pack years' of smoking 5. Medication/drug use Volunteers must not be taking any prescribed medications or over the counter medications, with an exception for birth control. 6. Prior shift work For stability of endogenous circadian rhythmicity, volunteers must have no history of the following 1 year prior to the study: * Working irregular day and night hours * Regular night work * Rotating shift work f * Not have traveled more than 1 time zone during 3 months prior to the study 7. Chronobiologic and sleep disorders * Hypernychthemeral sleep/wake cycle * Delayed sleep phase syndrome (wake time \> 2 hours later than desired or habitually after 10:00 AM) * Advanced sleep phase syndrome (wake time \> 2 h earlier than desired or habitually before 5:00 AM) * Narcolepsy * Sleep apnea (apnea index \>15) * Insomnia (sleep complaint by history or polygraphically recorded sleep efficiency \< 80%) * Hypersomnia * Periodic Limb Movement (PLMS) (PLMS index \>15) * Nocturnal Paroxysmal Dystonia * REM-sleep behavior disorder * Nocturnal Enuresis; (self-report and first night in the laboratory) * Obstructive sleep apnea (apnea/hypopnea index \>5/h as determined by at-home monitoring) * The investigators will also exclude individuals with extreme chronotype using the Horne-Ostberg Morningness/Eveningness questionnaire (i.e., the Owl/Lark Questionnaire) 8. Diseases of the Cardiovascular System * Hypertension (systolic blood pressure \> 140 or diastolic blood pressure \> 90) * Heart failure * Cardiomyopathy * Cor pulmonale * Ischemic heart disease * Valvular heart disease * History of heart transplantation * Cardiac tumors * Pericardial disease 9. Metabolic Syndrome Following American Heart Association cutoffs, participants who have, in addition to abdominal fat (obese exclusion criteria), two or more of these factors will be excluded from the study: * HDL cholesterol of less than 40 mg/dL in men or less than 50 mg/dL in women * Systolic blood pressure \>135 mmHg or diastolic blood pressure \>85 mmHg * Fasting blood glucose ≥ 100 mg/dL * Triglycerides ≥ 150 mg/dL 10. Pre-Diabetes/Diabetes For participants who have a fasting blood glucose level of ≥ 100 mg/dL the investigators will measure hemoglobin A1c to exclude for diabetes (HbA1c\>5.7%). 11. Hypertension An upper cut off of 140/90 mmHg during an office blood pressure measure will be used as an exclusion criterion. After 5 minutes of rest in a seated position, blood pressure will be measured 3 times, taken 1 minute apart. The average will be used to confirm eligibility criteria. Current or history of beta blocker use will also be exclusionary. 12. Disorders of the Respiratory System * Asthma * Cystic fibroses * Chronic bronchitis * Emphysema * Airway obstruction * Interstitial lung diseases * Pulmonary hypertension * Lung neoplasms * ARDS 13. Disorders of the Kidney and Urinary Tract * Acute or chronic renal failure * History of renal transplantation * Tubulointerstitial diseases of the kidney * Urinary tract obstruction * Tumors of the urinary tract 14. Infectious Diseases * Infective endocarditis * HIV infection * Sexually transmitted diseases \[e.g., syphilis (including congenital syphilis and its sequelae), gonorrhea\], * Urinary tract infection * Osteomyelitis * Brucellosis * Toxoplasmosis, * Tuberculosis * Leptospirosis * Lyme disease * Mononucleosis * Hepatitis * Parasitic infections such as malaria, toxoplasmosis, giardiasis, schistosomiasis, leishmaniasis 15. Disorders of the Gastrointestinal System * Esophagitis * Peptic ulcer and gastritis * Neoplasms of the esophagus, stomach or bowel * Disorders of absorption * Inflammatory bowel disease * Diseases of the small and