Exposure to cold activates brown fat cells in the body and they start burning calories. A new study suggests that this biological response is different depending on the time of day and gender. If you want to lose weight and have a good tone, it is recommended that men take cold showers in the morning, and women in the evening.
Every human body contains fat tissues that perform different functions depending on their type and are vital for the body. White fat cells, or white fat, store energy for later use. Accumulating too much white fat leads to obesity.
There is another type of adipose tissue in the body, which is relatively smaller in amount than white, but performs a different function. It’s called brown adipose tissue, or brown fat, and it reacts to cold temperatures. Its purpose is to maintain a normal body temperature by burning glucose and fat molecules in the body.
This boost in metabolism can be helpful in combating issues like obesity and diabetes, so a common recommendation for a healthy metabolism is cold showers. In addition to the sudden awakening effect, brown cells are activated and the metabolism goes into overdrive to maintain body temperature.
Not everyone experiences the same effect from cold exposure, according to a study conducted by scientists at Leiden University Medical Center in the Netherlands. It is obtained because, depending on the time of day and biological sex, differences in the metabolic activity of brown fat are observed.
Time of day is found to be significant for most effective exposure to cold. The body goes through a 24-hour cycle that includes sleep. Two hours before we wake up, our body temperature is at its lowest in the entire 24-hour cycle, and slowly begins to rise. Automatically upon awakening, the body is stimulated to raise its temperature in order to function normally. Due to the fact that brown cells are most active at this time of day, exposure to cold temperatures would be most successful in firing up the metabolism and burning extra fat.
It turns out that this method is most effective for men. The study observed cold exposure using water beds with gradually cooling water at different times of the day. In men, a greater expenditure of energy was observed in the morning hours, and in women – in the evening hours. In women, elevated cholesterol levels were observed with morning exposure to cold.
The paper was presented at the thirtieth European Congress on Obesity in Dublin, Ireland, May 17-20.