Staying indoors may contribute to obesity

Lee Ji-hyun, a 28-year-old office worker, plans to visit Bangkok next week during the Lunar New Year’s holiday.

“I just want to run away from the prolonged cold wave in Seoul. I’ve been scared to go out in recent weeks due to the very cold weather,” Lee said.

Indeed the worst cold spell in years continues to grip the nation. The temperature at Christmas fell to minus 14 degrees Celsius in Seoul, its lowest in three decades.

It is not surprising for people to keep warm at home rather than going outside. However, a new study has warned that higher indoor temperatures during winter are linked to obesity.

A team at University College London said Tuesday they have verified the link between reduced exposure to seasonal cold and the rise in obesity rates in the U.K. and the U.S.

Reduced exposure to cold may affect the body’s ability to maintain a healthy weight by minimizing energy expenditure to stay warm, as well as reducing the body’s capacity to produce heat, said the researchers.

“Increased time spent indoors, widespread access to central heating and air conditioning, and increased expectations of thermal comfort all contribute to restricting the range of temperatures we experience in daily life and reduce the time our bodies spend under mild thermal stress ― meaning we’re burning less energy. This could have an impact on energy balance and ultimately have an impact on body weight and obesity,” Fiona Johnson, a research psychologist who led the study, said in a press release.

“Research into the environmental drivers behind obesity, rather than the genetic ones, has tended to focus on diet and exercise, which are undoubtedly the major contributors. However, it is possible that other environmental factors, such as winter indoor temperatures, may also have a contributing role. This research therefore raises the possibility for new public health strategies to address the obesity epidemic,” she said.

There are two types of adipose tissue in human bodies ― white fat and brown fat. Unlike white fat which is used as a store of energy, brown fat plays a key role in helping the body generate its own heat.

According to the researchers, more time spent indoors resulted in a loss of brown fat and reduced body’s capacity to generate heat. And the development of brown fat was believed to be triggered by exposure to cold temperatures, they said.

Their findings were also published in the current issue of the journal Obesity Review.

By Lee Ji-yoon (jylee@heraldcorp.com)