Walking briskly for just an hour a day is enough to cut the effect of genetic tendencies toward obesity, according to new research.
Researchers from the Harvard School of Public Health also found that staying sedentary -- measured in the study by how long a person watched TV per day -- worsened the effects of the "obesity genes."
"In our study, a brisk one-hour daily walk reduced the genetic influence towards obesity, measured by differences in BMI by half," study researcher Qibin Qi, Ph.D., a post doctorate research fellow at Harvard, said in a statement. "On the other hand, a sedentary lifestyle marked by watching television four hours a day increased the genetic influence by 50 percent."
The research was presented at the American Heart Association's Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism 2012 Scientific Sessions.
Qi and colleagues analyzed data from 7,740 women and 4,564 men who were part of the Nurses' Health Study and the Health Professionals Follow-Up Study. They looked at the study participants' physical activity and TV watching habits two years before they looked at their body mass indexes (BMI, a ratio of weight to height that tells whether a person is obese or overweight).
The researchers then scored each person on their genetic predisposition toward obesity, based on 32 established genetic variants. They found that with each gene that a person had, it was associated with 0.13 kilograms per meter squared in the BMI.
However, the people who exercised the most in the study had a lowered effect of the gene, at just 0.08 kilograms per meter squared, compared to the 0.13 kilograms per meter squared, according to the research.
On the other hand, researchers found that watching TV for 40 hours a week increased the effects of an obesity gene -- from 0.13 kilograms per meter squared to 0.34 kilograms per meter squared.
"These genes were just identified in the past five years and the exact functions of the genetic variants are still unknown," Qi said in the statement. "Future studies will be needed to uncover the underlying mechanisms."
This isn't the first study to show that exercise can have effects against obesity genes. Research published last year in the journal PLoS Medicine showed that just 30 minutes of exercise -- whether it be riding a bike or gardening -- for five days during the week can counteract obesity genes, TIME reported.
Last year, a study in Menopause: The Journal of the North American Menopause Society suggested that walking at least 10,000 steps a day doesn't necessarily boost muscle strength or balance for women, but it does have effects on decreasing body fat and weight. The women in that study were between 50 and 70 years old, Reuters reported.