Energy Expenditure Responses to Different Temperatures
Public ClinicalTrials.gov record NCT01568671. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
Background: \- The way that the body burns calories is known as energy expenditure. Some studies show that when we are cold, we burn more calories to keep our bodies warm. Brown fat is a special kind of fat that can use energy to keep the body warm. Small animals and infants have been known to have brown fat for many years. Recently, it has been suggested that adult humans also have brown fat. If brown fat becomes active (burns calories) in adult humans when exposed to cold, then these people would tend to burn off more calories and might not gain weight easily. Learning more about the relationship between energy expenditure, brown fat, environmental temperature, and body temperature may help explain why some people become obese and other people do not. Objectives: * To better understand how the body burns calories when exposed to different temperatures. * To study brown fat and how it burns calories in cold temperatures. Eligibility: * Healthy men between 18 and 35 or 55 and 75 years of age. * Healthy women between 18 and 35 years of age. * To control for ethnicity, participants must be non-Hispanic whites or African Americans. Design: * Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected. * Participants will stay in the Metabolic Unit of the National Institutes of Health Clinical Center as inpatients for no more than 14 days. The length of the hospital stay will depend on how participants respond to the different study temperatures. * Every afternoon, participants will walk for 30 minutes on a treadmill. All meals will be provided. * Participants will stay up to 5 hours per day in a specialized room with different temperature settings. Temperatures will range from about 61 degrees to 88 degrees Fahrenheit. Body temperature, activity, calorie burning, and cold/hot sensations will be monitored. On the study day of the coldest temperature, participants will have an imaging study to look for brown fat activity. * Participants will be compensated for their time and participation at the end of the study.
Study identification
- NCT ID
- NCT01568671
- Recruitment status
- Completed
- Study type
- Interventional
- Phase
- Not applicable
- Enrollment
- 104 participants
Conditions and interventions
Conditions
Eligibility (public fields only)
- Age range
- 18 Years to 75 Years
- Sex
- All
- Healthy volunteers
- Accepts healthy volunteers
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Apr 23, 2012
- Primary completion
- Nov 13, 2019
- Completion
- Nov 13, 2019
- Last update posted
- Aug 26, 2026
2012 – 2019
United States locations
- U.S. sites
- 1
- U.S. states
- 1
- U.S. cities
- 1
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| National Institutes of Health Clinical Center | Bethesda | Maryland | 20892 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT01568671, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Aug 26, 2026 · Synced Sep 2, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT01568671 live on ClinicalTrials.gov.