Obese women get only one hour of vigorous exercise a year and obese men get less than four, according to a recent study HealthDay reported.

The findings startled researchers from the University of South Carolina whose main focus was to develop a new method for calculating physical activity, sedentary behavior and food energy requirements, HealthDay reported.

"They're living their lives from one chair to another," Edward Archer, a research fellow with the Nutrition Obesity Research Center at the University of Alabama at Birmingham who was at the University of South Carolina when the study was conducted, told HealthDay. "We didn't realize we were that sedentary. There are some people who are vigorously active, but it's offset by the huge number of individuals who are inactive."

For the study, researchers tracked the weight, diet, and sleep patterns of nearly 2,600 adults aged 20 to 74, between 2005 and 2006. Study participants in the study wore accelerometers that tracked their movements and provided data about how much they exercised and ad at what intensity.

The study defined "vigorous" exercise as fat-burning activities like jogging and jumping rope, but not sexual activity. For some severely obese people, walking could be a vigorous activity.

Based on their findings, the average obese woman gets the equivalent of about one hour of exercise a year. For men, it's 3.6 hours a year, HealthDay reported.

"The data was there, but no one looked at it and parsed it the way we did," Archer said. Overall, "there is a great deal of variability; some are moving probably a fair amount. But the vast majority [of people] are not moving at all."

More than one in three people in the United States is obese, a step above being overweight, according to the U.S. Centers for Disease Control and Prevention. Obesity boosts the risk of cardiovascular problems such as heart disease and stroke, diabetes and some cancers.

The federal recommendation for exercise is at least 2.5 hours of moderate-intensity aerobic exercise every week.

The study recently appeared in the Mayo Clinic Proceedings.