Energy Expenditure Responses to Different Temperatures

Launched by NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES (NIDDK) · Mar 30, 2012

Keywords

ClinConnect Summary

This clinical trial is studying how our bodies burn calories at different temperatures, specifically looking at a type of fat called brown fat that helps keep us warm. Researchers want to see if being in colder temperatures makes this brown fat more active in adults, which could help prevent weight gain. By understanding how temperature affects calorie burning, the study aims to figure out why some people are more likely to become obese than others.

The trial is open to healthy men aged 18-35 or 55-75, and healthy women aged 18-35 who are non-Hispanic whites or African Americans. Participants will stay at the National Institutes of Health Clinical Center for up to 14 days, where they'll have regular check-ups, walk on a treadmill for 30 minutes each day, and spend time in rooms set to different temperatures. They will also have meals provided and be compensated for their participation. Before joining, everyone will go through a health screening to ensure they meet the study's health criteria.

Gender

ALL

Eligibility criteria

• * INCLUSION CRITERIA:
• • Generally healthy.
• • Males between the age greater than or equal to 18 -35 years or between 55-75 years, male orand females between the age 18-35 years.
• • Self-reported non-Hispanic and non-Latino Caucasian and African-Americans
• • Written informed consent.
• EXCLUSION CRITERIA:
• • Hypo- or hyper-thyroid (history or TSH \>5.0\<0.4 miU/L)
• • Psychological conditions,such as (but not limited to) claustrophobia, clinical depression, bipolar disorders, that would be incompatible with safe and successful participation in this study
• • Weight change \>5% in the past 6 months or a trained athlete
• • Blood pressure greater than 140/90 mmHg or current antihypertensive therapy
• • History of cardiovascular disease
• • BMI \<18.5, between 25.1-29.9, and \>40 Kg/m(2)
• • Diabetes mellitus (fasting serum glucose \> 126 mg/dL)
• • Liver disease or ALT serum level greater than two times the laboratory upper limit of normal
• • Iron deficiency (Ferritin \< 30 mcg/L males, \< 15 mcg/L females)
• • Abnormal kidney function (eGFR\<60 ml/min/1.73m(2))
• • History of illicit drug or alcohol abuse within the last 5 years; current use of drugs (by history) or alcohol (CAGE greater than or equal to 2)
• • Current use of medications/dietary supplements/alternative therapies known to alter energy metabolism
• • Pregnancy/breastfeeding/hormonal contraception or childbirth within the last year
• • Perimenopausal (as self-described within two years from onset of amenorrhea or current complaints of hot flashes)
• • For pre-menopausal women, irregular periods or polycystic ovarian disease
• • Current smoker or user of tobacco products
• • Metal implant that prevents subject from being in a MRI scanner.
• • All subjects will be fully informed of the aims, nature, and risks of the study prior to giving written informed consent.