Taking a walk during the early hours of the morning when there's bright light can help you lose weight, according to a new study.
The world is becoming more fitness conscious. People are always on the lookout for ways to shed those extra pounds. A new study by Northwestern University revealed an interesting way to lose weight and it's very simple. According to the researchers, taking a walk during the early hours of the morning when there's bright light can help you lose weight.
The study found that people who had most of their daily exposure to even moderately bright light in the morning had a significantly lower body mass index than people who were exposed to sunlight later in the day.
"The earlier this light exposure occurred during the day, the lower individuals' body mass index," said co-lead author Kathryn Reid, research associate professor of neurology at Northwestern University Feinberg School of Medicine in a statement. "The later the hour of moderately bright light exposure, the higher a person's BMI."
Researchers also stated that exposure to morning light accounts for 20 percent of a person's BMI and is independent of an individual's physical activity level, caloric intake, sleep timing, age or season.
"Light is the most potent agent to synchronize your internal body clock that regulates circadian rhythms, which in turn also regulate energy balance," said study senior author Phyllis C. Zee, according to Live Science. "The message is that you should get more bright light between 8 a.m. and noon." About 20 to 30 minutes of morning light is enough to affect BMI.
The study was conducted on 54 participants (26 males, 28 females) with an average age of 30. Researchers monitored their sleep parameters and calories intake for seven days. During this period, the participants wore a wrist actigraphy monitor so that researchers could record their light exposure.
With the information gathered, researchers tried linking light exposure timing, duration or intensity with BMI. No association was found when each parameter was considered individually. However, when they were combined, researchers were able to determine a correlation.
"I saw that what seemed to be most associated with body mass index was not just how much light you receive but when you get it and for how long," co-lead author Giovanni Santostasi said, according to NBC News. "Light is a modifiable factor with the potential to be used in weight management programs. Just like people are trying to get more sleep to help them lose weight, perhaps manipulating light is another way to lose weight."
The Correlations Between Light Exposure And Lower BMI
Insufficient exposure to morning light is believed to de-synchronize an individual's internal body clock. This alters metabolism and leads to weight gain.
"We focus on how too much light at night is bad; it's also bad not to get enough light at the appropriate time during the day," Zee said, according to Los Angeles Times.
500 lux of light is the minimum threshold to maintain a lower BMI. Owing to the American lifestyle, which is predominantly indoors, people get about 200 to 300 lux of light daily. However, outdoor light is more than 1,000 lux of brightness even on a cloudy day.
Since most offices and schools are poorly lit, researchers recommend that these buildings should consider having more widows that allow natural light to enter the rooms. Indoor lighting should also be improved and employees and students should be encouraged to go outdoors for breaks.
Does This Explain Why Night Shift Workers Are At A Higher Risk of Obesity?
A previous study found that people who work night shifts are at a higher risk of obesity and diabetes. While the study highlighted lack of sleep as the main cause of weight gain, this study can help throw more light on the subject.
"Since night workers often have a hard time sleeping during the day, they can face both circadian [body clock] disruption working at night and insufficient sleep during the day," Dr Orfeu Buxton, lead researchers of the previous study said, according to BBC News. "The evidence is clear that getting enough sleep is important for health, and that sleep should be at night for best effect."
People who work night shifts are generally sleeping through the day. Hence, there are lesser chances that they get adequate exposure to natural morning light.
Another benefit of being exposed to morning light is that it enhances sleep quality, eradicating obesity problems yet again. The light regulates a person's biological clock and keeps it on track, according to a health report.
Researchers of the new study said that more research needs to be conducted to better understand why exposure to light at particular times of the day is associated with lower BMI.
The current study was published in the journal PLOS ONE and funded by National Heart, Lung and Blood Institute, National Institute on Aging and the Office of Research on Women's Health.
