A new study has said that extended sedentary behaviour of two or more hours could be as harmful to fitness levels as short workouts are beneficial.

For the benefits of an hour-long workout, six hours spent sitting is as harmful to cardiorespiratory fitness, according to the study carried out by a team of cardiologists at the University of Texas Southwestern Medical Centre.

Using data from 2,223 participants in the National Health and Nutrition Examination Survey (NHANES), the study examined cardiorespiratory fitness levels in relation to exercise and the amount of time spent sedentary in conjunction with that.

Participants taking part included men and women aged 12 to 49 with no known history of heart disease, asthma or stroke, and the fitness levels were assessed through a submaximal treadmill test, which was adjusted for differences in gender, age and body mass index.

"Previous studies have reported that sedentary behaviour was associated with an increased risk for cardiovascular outcomes," said Dr Jarett Berry, assistant professor of internal medicine and clinical science and senior author of the study. "However, the mechanisms through which this occurs are not completely understood.

"Our data suggest that sedentary behaviour may increase risk through an impact on lower fitness levels and that avoiding sedentary behaviour throughout the day may represent an important companion strategy to improve fitness and health, outside of regular exercise activity."

Offering ways to avoid extended sedentary behaviour, UT Southwestern preventative cardiologists recommended using a pedometer to track daily motion and replacing office desk chair’s with fitness balls.