Friday, March 29, 2024
News

Research shows how time of day determines effectiveness of cold exposure in fat burning

   SocialTwist Tell-a-Friend    Print this Page   COMMENT

Washington | May 28, 2023 4:39:47 PM IST
Short-term exposure to cold temperatures stimulates brown fat, which burns calories and has emerged as a popular target for promoting cardiometabolic health.

This year's European Congress on Obesity (ECO) will be held in Dublin, Ireland (17-20 May), and new study will be presented there that reveal this biological reaction varies depending on the time of day and between men and women.

According to a preliminary study by Dr. Maritte Boon and colleagues from Leiden University Medical Centre in the Netherlands, exposure to cold in the morning may enhance metabolism and burn fat more effectively than exposure to cold in the evening in males, but perhaps not in women.

Brown fat or brown adipose tissue (BAT) is a distinct type of fat that is activated in response to cold temperatures. Its primary role is to produce heat to help maintain body temperature and it achieves that by burning calories especially from fat.

"Our study indicates that the optimum time to undergo cold exposure is at a specific point in the body's 24-hour cycle," says Dr Boon. "It may also be that there is a sex difference in how the body responds to cold exposure with respect to boosting metabolism at a certain time point, and it appears that delivering cold exposure therapies in the morning may be more beneficial than the evening for men."

In rodents, brown fat metabolic activity fluctuates throughout the day, and is highest just before waking up. This makes biological sense because heat production from food digestion and activity declines during night-time and waking up requires the body to increase its core body temperature. But whether there is a circadian rhythm in brown fat activity in humans, and whether it differs in men and women when they are exposed to cold, is unknown.

To find out more, researchers conducted a randomised crossover study in 24 lean adults--12 men (aged 18-31 years; BMI 18-26 kg/m2) and 12 women (aged 18-29 years; BMI 18-26 kg/m2).

Participants underwent a 2.5 hour personalised cooling protocol using water-filled mattresses in the morning (7:45 am) and evening (7:45 pm), in random order and with one day in between these study days.

The water temperature was lowered gradually until shivering occurred or until a temperature of 9C was reached. Participants were then exposed to stable cold for another 90 minutes.

Researchers measured energy expenditure (using indirect calorimetry) four times during the experiment--at the start under thermoneutral conditions (at 32C when the body does not need to produce extra heat to maintain its core temperature), during the cooling down phase, the stable cold phase, and at the end of cooling (after 90 minutes). Supraclavicular skin temperature was also measured regularly with infrared thermography.

The analysis found that in men, cold-induced energy expenditure and skin temperature (both a proxy for brown fat activity) were higher in the morning than in the evening.

However, cold-induced energy expenditure and skin temperature did not differ between the morning and the evening in females, while the females were more tolerant to cold in the morning than in the evening (meaning they started shivering at a lower temperature in the morning).

Moreover, in women, circulating free fatty acid concentrations, triglycerides, and cholesterol levels were higher after cold exposure in the morning than in the evening.

The authors note several limitations including the inability to draw strong causal conclusions about the direct effect of cold exposure on cardiometabolic health. They also note that despite measures taken to control diet and sleep, other unmeasured lifestyle or genetic factors could have influenced the results.

"Nevertheless, this is an important first step investigating the effects of circadian rhythm on the effects of cold exposure on (fat) metabolism. We are currently studying whether repeated bouts of cold exposure in the morning improves cardiometabolic health in individuals with obesity. At the very least, our findings indicate that administering interventions at specific times should be considered when targeting lipid metabolism," said Dr Boon. (ANI)

 
  LATEST COMMENTS ()
POST YOUR COMMENT
Comments Not Available
 
POST YOUR COMMENT
 
 
TRENDING TOPICS
 
 
CITY NEWS
MORE CITIES
 
 
 
MORE HEALTH NEWS
Study finds how childhood sedentariness ...
Longer genes are associated with ageing...
Dr. Dangs Lab aims to revolutionise heal...
Researchers find ways to reduce side eff...
Study gives insight into role of specifi...
Collaborative study between bariatric, t...
More...
 
INDIA WORLD ASIA
Uttar Pradesh: Security tightened in Ali...
'Three parties have allied directly...':...
Eknath Shinde's Shiv Sena releases first...
Jailed gangster-turned-politician Mukhta...
Chennai: Three dead after false ceiling ...
'My father was being given slow poison; ...
More...    
 
 Top Stories
Pakistan Tehreek-e-Insaf to hold ra... 
Miami Open: Bopanna-Ebden storms in... 
Anju Bobby questions IOA's decision... 
"Three parties have allied directly... 
8 people killed after pickup truck ... 
IPL 2024: Rishabh Pant feels 'disap... 
Eknath Shinde's Shiv Sena releases ... 
"Thought we could win series": Craw...