A recent study has found that sedentary behaviours may lower cardiorespiratory fitness levels. The study suggests that two hours of sedentary behaviour can be just as harmful as 20 minutes of exercise is beneficial.
The study, from UT Southwestern Medical Center, examined the association between fitness levels, daily exercise and sedentary behaviour, based on data from 2,223 participants in the National Health and Nutrition Examination Survey.
Sedentary behaviour involves low levels of energy expenditure activities such as sitting, driving, watching television and reading, among others. The findings suggest that sedentary behaviour may be an important determinant of cardiorespiratory fitness, independent of exercise.
“Previous studies have reported that sedentary behaviour was associated with an increased risk for cardiovascular outcomes; however, the mechanisms through which this occurs are not completely understood,” said Jarett Berry, assistant professor of internal medicine and clinical science and senior author of the study. “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.”
The team of physician-researchers analyzed accelerometer data from men and women between the ages of 12 and 49 with no known history of heart disease, asthma or stroke, and measured their average daily physical activity and sedentary behaviour times. Fitness was estimated using a submaximal treadmill test, and variables were adjusted for gender, age and body mass index. The findings demonstrate that the negative effect of six hours of sedentary time on fitness levels was similar in magnitude to the benefit of one hour of exercise.
“We also found that when sitting for prolonged periods of time, any movement is good movement, and was also associated with better fitness,” said Jacquelyn Kulinski, a recent graduate from the UT Southwestern Cardiology Fellowship Training Program and first author of the paper. “So if you are stuck at your desk for a while, shift positions frequently, get up and stretch in the middle of a thought, pace while on a phone call, or even fidget.”
To stay active and combat sedentary behaviour, UT Southwestern preventive cardiologists recommend taking short walks during lunch and throughout the day, using a pedometer to track daily steps, taking the stairs instead of the elevator, hosting walking meetings at work, and replacing a standard desk chair with a fitness ball or even a treadmill desk, if possible.