‘How much time do you spend riding in a car, working at a desk, eating at a table, playing video games, using a computer, watching TV, or engaged in other sedentary pursuits?’
It may be a problem-even if you exercise regularly.
Here are the main points from an internet article written by ex Body Building Champion Clarence Bass (http://www.cbass.com/Sitting.htm). He quotes 3 main studies, as outlined below:
Owen, N, et al comment in the British Journal of Sports Medicine (2009:43;81-83) that the widely recommended 30 minutes of moderate to vigorous activity 3-5 days a week may not alone be sufficient. They write that “Recent evidence underlines the importance of also focusing on sedentary behaviours—the high volume of time that adults spend sitting in their remaining ‘non-exercising’ waking hours”.
They continue: “Our recent body of work has identified sedentary behaviour as a novel and potentially important risk factor for development of chronic disease. There may be significant metabolic and health effects from prolonged sitting”. Weight gain and blood glucose control were just two areas of concern raised.
The researchers state that most adults spend more than half of their waking hours in sedentary activities, with the remainder of the time spent in light intensity activities (standing with some movement). “Only about 4.5% of the day is spent in moderate to vigorous physical activity”.
Owen et al emphasise that we need to begin thinking about ways to break periods of prolonged sitting. “Common sense might suggest that it may be prudent to try to minimise prolonged sitting with 5 minute breaks every hour”.
Katzmarzyk, P, et al, (Medicine & Science in Sports & Exercise :41, 5, 998-1005, 2009) followed 17,013 Canadian men and women 18-90 years of age for an average of 12 years, looking into the relationship between sitting time and deaths from all causes, and from cardiovascular disease (CVD).
They found a progressively higher rate of mortality (all cause and CVD) as sitting time increased. Importantly, it didn’t make any difference whether subjects were otherwise active or inactive, death rates were essentially the same for those who exercised regularly and those who didn’t.
The researchers concluded: “This data demonstrate a clear association between sitting time and mortality from all causes and CVD, independent of leisure time physical activity.”
A third study by Hamer,M et al, reported in the Scandinavian Journal of Medicine and Science in Sports (2008; 18: 736-741) investigated the independent effect of walking on two markers of cardiovascular health.
The authors suggested that walking may have unique positive effects on inflammation and, hemostasis both markers of cardiovascular health. Inflammation is a central factor in atherosclerosis . Hemostasis refers to blood thickness and is also an important factor in atherosclerosis.
Walking 30 minutes or more a day was found to be significantly associated with lower inflammation and hemostasis markers. Vigorous activity was associated with lower levels of hemostatic markers, but not lower inflammatory markers.
Walking appeared to lower both markers, with the positive effect on inflammation being unique. Walking lowered inflammation, but vigorous exercise did not. Both walking and vigorous exercise improve blood flow.
Assuming that the association is causal, the researcher estimated that “meaningful reductions in levels of homeostatic and inflammatory markers could be achieved by walking 30 min/day.”
Take Home Message
Those who engage in vigorous exercise, especially those who train only once a week, would be well advised to walk or engage in some other form of moderate physical activities on most intervening days. It is important to keep walking & stay active in other ways between workouts. Finally, make it a point to get up and move around periodically when working at your desk or computer!
Thanks for reading,