Clinical Research Directory

Inclusion Criteria: 1. Young: 18-30 years of age, Old: 55-75 years of age 2. Apparent healthy 3. BMI (body mass index) up to 27.4 4. Upper arm with intact skin, i.e. without areas of breached or injured skin visible, for ambulatory blood pressure (ABP) measurements, 5. Own and use a smartphone. Exclusion Criteria: 1. History of severe psychiatric illness or cognitive conditions, for example (mania, schizophrenia, or mental retardation; 2. Shift work, defined as recurring work between 22:00-05:00; 3. A diagnosis of clinically significant obstructive sleep apnea; 4. Serum creatinine \> 1.5 mg/dl in men or \>1.3 mg/del in women; 5. Significant liver disease (\>3x upper limit of normal); 6. Diabetes mellitus; 7. Past diagnosis of gastroesophageal reflux disease, 8. Transmeridian travel across ≥3 time zones in the two weeks before the 48hr deep phenotype sessions; 9. Use of oral or intravenous antibiotics in the 6 months prior to enrollment; 10. Subjects, who have received an experimental drug, used an experimental medical device within 30 days prior to screening, or who gave a blood donation of ≥ one pint within 8 weeks prior to screening; 11. \> 2 drinks of alcohol per day; 12. Use of drugs assessed in the urinary drug test; 13. Nursing or pregnant (pregnancy will be repeatedly assessed at the beginning of each of the four inpatient visits, i.e. prior to the start of blood draws); 14. Use of pacemaker or implantable Cardioverter Defibrillator (ICD); 15. Bilateral mastectomy; 16. History of Raynaud's phenomenon; 17. Known allergy against natural latex rubber (contained in ABP bladder and tubing); 18. Subjects taking medication with alpha-blockers.