RecruitingNAINTERVENTIONAL

Intermittent Cold Exposure and Brown Adipose Tissue Hyperplasia

This study explores how being in the cold for short periods affects a particular type of body fat known as brown fat. Brown fat is interesting because it helps burn calories and produce heat, which might be good for your heart and overall metabolism. While we know that cold can make brown fat more active, scientists don't fully understand the detailed changes that happen inside these fat cells, or in other tissues like muscle and white fat. Researchers will ask healthy adults to spend short periods in cold conditions for 10 days. They will then look closely at how the body, and especially these fat and muscle cells, react to the cold. The aim is to find out exactly what changes happen at a tiny level, which could help us learn more about keeping our bodies healthy.

At a glance

Status

Recruiting

Phase

Sponsor

University of Edinburgh

Enrolment target

Start

01 May 2025

Estimated completion

01 Jul 2026

Brown Adipose Tissue Cold Exposure 18F-FDG PET/CT

What is this study about?

You might have heard of brown fat, sometimes called 'good fat.' Unlike white fat, which stores energy, brown fat burns calories to produce heat. Scientists believe that having more active brown fat could help improve your heart health and metabolism – how your body uses energy. We know that being a bit cold can make brown fat more active and even increase its amount, but we don't fully understand *how* it does this on a very detailed level.

This study wants to uncover these secrets. Researchers will ask a small group of healthy adults to spend short periods in a cool environment over 10 days. They will carefully check what happens to their brown fat, as well as their ordinary white fat and muscles. They will look at changes in how these tissues work and even the genes that are switched on or off inside the cells. This could help us understand the body's natural response to cold much better.

The main goal is to see how regular, short cold exposures change the cells and genes in brown fat, white fat, and muscles. By understanding these tiny changes, scientists hope to learn more about how brown fat can improve health and potentially find new ways to help people stay healthy in the future. This is a step towards understanding our bodies better, not to recommend cold exposure as a treatment right now.

Key takeaways

This study investigates how cold exposure affects 'good' brown fat.
It aims to understand detailed changes in fat and muscle cells from cold.
Participants will have short daily cold exposures for 10 days.
The study involves blood tests, body scans, and small tissue samples (biopsies).
Results could help us learn about improving heart and metabolism health.
Volunteers need to be healthy adults aged 18-40.

Who may be eligible?

This study is looking for a small group of healthy adults, specifically 6 men and 6 women. To join, you should be between 18 and 40 years old and have a healthy weight (your Body Mass Index or BMI should be between 18.5 and 25).

It's important that you are generally well and haven't had any major changes in your weight recently (less than 5% change in the last 6 months). You shouldn't have any ongoing medical conditions or be taking regular medications, though women who are taking contraception are still able to join. You also shouldn't be pregnant, breastfeeding, or planning to become pregnant during the study.

For your safety and the accuracy of the study results, you should not have claustrophobia (a fear of small, enclosed spaces) as some tests involve being in a scanner. Your alcohol intake should also be moderate, no more than 14 units per week. The researchers will do some blood tests at the start to make sure you are healthy enough to take part.

Quick self-check

Are you between 18 and 40 years old?
Is your weight healthy (BMI 18.5-25)?
Are you generally healthy and not on regular medication (except contraception)?
Are you comfortable in small spaces (not claustrophobic)?
Are you currently not pregnant or breastfeeding?
Can you commit to daily cold exposure for 10 days and study visits?

This is a guide only — the research team will confirm whether you can take part.

What does participation involve?

If you decide to take part, you'll have several visits to the study centre. First, you'll have some initial checks, including blood tests, measurements of how much energy your body uses, and your body temperature. You'll also have a special scan called a PET/CT while in a cold environment. Then, a doctor will take tiny samples (biopsies) of your brown fat (from above your collarbone), muscle (from your thigh), and white fat (from your tummy). This is done using local anaesthetic to numb the area, so it shouldn't be too painful.

After these initial checks, you will take part in a 10-day programme where you'll spend two hours each day in a slightly cold environment. This will involve using special blankets that have cool water flowing through them. After these 10 days, you'll repeat all the initial checks – the blood tests, energy and temperature measurements, the PET/CT scan, and the small tissue biopsies. This will allow the researchers to see what changes have happened in your body. In total, the study involves several visits spread over a few weeks.

Potential risks and benefits

Taking part in this study could help researchers learn more about how brown fat works and its potential benefits for health, which could ultimately help many people in the future. However, there are also some risks. You might feel uncomfortable during the cold exposure sessions, and the biopsies involve small procedures where you might experience some bruising, soreness, or a small risk of infection. The PET/CT scan involves a very small amount of radiation, similar to what you might experience from natural sources over a year. You have the right to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Royal Infirmary of Edinburgh
Edinburgh, United Kingdom· Recruiting

Common questions

What is brown fat?

Brown fat is a special type of fat in your body that burns calories to produce heat, unlike white fat which stores energy.

Why are researchers interested in cold exposure?

Researchers are interested because short periods of cold can make brown fat more active, which might have benefits for heart health and metabolism.

Will I feel very cold during the study?

You will be exposed to a cool temperature for two hours a day, using special cooling blankets, to encourage your body to activate brown fat.

What are biopsies?

Biopsies are small samples of tissue taken from your body, like fat or muscle, usually with a needle after numbing the area. They help doctors look at cells up close.

Will taking part impact my daily life?

You'll need to attend study visits for assessments and spend two hours a day for 10 days in a cool environment, which will require some commitment.

How to find out more

María Paula Huertas Caycedo

m.p.huertas-caycedo@sms.ed.ac.uk 01312429196 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.