Aging Program Project Grant 6

Inclusion criteria

• Older adults 55-75 years old.
• Females must be post-menopausal.
• BMI 25-45
• Regular eating schedule (consuming at least 2 meals/day) and sleeping schedules (deviation of ≤ 2 hours in daily mid-sleep time).
• Self-report sleep duration of ≥ 6.5 hours.
• Habitual mid-sleep time of 1-5 am.
• Habitual time in bed less than 9 hours
• HbA1c <6.5
• Habitual overnight fast of ≤ 13 hour (Determined by a mean overnight fast ≤ 13 hours over 3 days of self-monitoring of food intake)

Exclusion criteria

• History or current diagnosis of a primary sleep disorder (Chronic insomnia, restless leg syndrome, parasomnias, sleep apnea).
• AHI ≥30
• History of anemia.
• Diagnosis of diabetes or currently on any medications for diabetes.
• Endocrine dysfunction including PCOS.
• History of cognitive or other neurological disorders.
• History of DSM-V criteria for any major psychiatric disorder.
• Beck depression Index (BDI) of ≥16 indicating moderate depression.
• Mini mental status Exam <26 indicating cognitive impairment.
• Unstable or serious medical conditions.
• Individuals with pacemakers, defibrillators, mediation pumps, or any other implanted device.
• Any GI disease that requires dietary adjustment.
• Current or use within last month of melatonin.
• Current use of psychoactive, hypnotic, stimulants, or pain medications.
• Current use of hormone replacement therapy.
• Shift work or other self-imposed irregular sleep schedules.
• History of habitual smoking (≥6 cigarettes/week).
• Caffeine consumption >400 mg/day.
• Medically managed or self-reported weight loss program within past 6 months.
• Bariatric weight loss surgery.
• Blindness or visual impairment other than glasses.
• Allergic to heparin.
• Adults unable to consent will be excluded.
• Pregnant women will be excluded.
• Prisoners will be excluded.
• Individuals who are not yet adults (infants, children, teenagers) will be excluded.