Study Purpose: To determine how working a nighttime shift impacts your metabolism. To be enrolled in this study, you must meet certain requirements. You may be eligible to participate if you meet the following criteria:

Study Duration: 2-year enrollment, ~30 day participant remain in study

Study Commitment: 30 days, includes 2-night stay at TRI, mixed meal tolerance test, exercise testing, wearing a continuous glucose monitor, activity monitor, answering a questionnaire, two muscle biopsies, and whole room calorimetry

Age: 21-45 years old

Sex: Male & Female

Conditions/Eligibility:

• Employed as a healthcare worker in either dayshift or nightshift work
• Stable weight (+/- 3 kg over the past 6 months)
• BMI between 18.5-29.9 kg/m
• Understands the procedures and agrees to participate by giving written informed consent, willing and able to comply with scheduled visits, laboratory tests, and other study procedures

Study Procedures: screening visit, vital signs, medication review, eligibility, shift work history, medical history, physical examination, anthropometrics, urinalysis, toxicology screen, pregnancy test, fasting blood collection, electrocardiogram, DXA scan, free-living assessment, physical activity profile, continuous glucose monitor, muscle biopsy, inpatient phenotyping, whole room indirect, calorimeter, mixed meal tolerance test, time series blood draw, core temperature pill, morning and evening questionnaires.

Compensation: $1200.00