Implications of sitting, standing and walking on health

With busy and long work schedules, longer travel times to workplaces, increasing automation of chores at homes and, more importantly, time being increasingly spent in front of TVs, physical inactivity or sedentary lifestyle has become a norm. And the hallmark of such a lifestyle has been spending more and more time in the sitting posture.Various studies were done on the benefits of exercise and the deleterious affects of prolonged sitting. Interesting and valuable information emerged from these studies.

Sitting, standing and ‘non-exercise physical activity’: If one considers what people do when they are awake during the course of a day, it is not uncommon for them to spend more than half the time sitting with relatively idle muscles, and the rest of the time doing what is termed ‘non-exercise physical activity’, which includes standing, walking casually or moving parts of the body, all of which burn more calories than just sitting. Owing to the longer duration of ‘non-exercise physical acivity’, it is the main consumer of calories in a day and not the shorter duration ‘exercise activity’ if there happens to be any.

Sitting is much more an idle activity than standing is. The latter involves work by the many skeletal muscles in the legs, back and trunk. Studies have proven that risk of death from cardiovascular disease was greater in people who sit for a long duration (eg. bus drivers). This was independent of the stress factor and the other risk factors. Prevalence of type 2 diabetes, obesity and deep vein thrombosis were also higher in people who spend more time sitting. Some experts believe that promotion of ‘non-exercise physical activity’ is more practical to implement.

Dr Mike Loosemore, head of exercise medicine at the Institute of Sport Exercise and Health at University College, London, and a leading sport medicine consultant, says that standing or being in an upright posture for three hours, five days a week, is as effective as running ten marathons a year and can extend life by two years!

Brisk walking – a moderate intensity exercise: Whereas casual walking is considered a non-exercise physical activity, brisk walking is a recommended moderate intensity aerobic exercise that would benefit the heart, lungs and improve insulin sensitivity if done at least for 150 minutes every week. This could be done as 30 minutes per day on most days of the week or distributed over at least 3 days in a week with not more than 2 consecutive days without physical activity.

It is even more beneficial if this is done for four or more hours every week. For weight loss 60 to 90 minutes of brisk walking is recommended on most days of the week along with diet and behaviour modification. Moderate intensity exercise is working at 50-70 per cent of maximum heart rate. Simplified brisk walk is walking fast enough to cause mild difficulty in conversing with a co-walker but not so fast to experience difficulty in breathing. Jogging and running are considered as vigorous physical activities, 75 minutes per week is equivalent to the 150 minutes of brisk walking. People with knee problems may be advised to perform non-weight bearing aerobic exercises like cycling and swimming.

The previously disapproved ‘resistance exercises’ which involve lifting weights, stretching resistance bands have found favour again and are now advised at least twice weekly using appropriate weight for the exercises targeting all groups of muscles. Unlike aerobic exercises and resistance exercises, stretching exercises have not shown to improve cardiovascular fitness or insulin sensitivity. In this context, yoga may be considered.

It is important for people new to either aerobic or resistance exercises to start low and go slow, building up gradually to the recommended levels. Exercise time can be divided into different sessions in a day. Wearing proper foot-wear is mandatory. Doctor’s advice must be sought for those with medical problems. People with advanced retinopathy and autonomic neuropathy may need to avoid intense exercise programmes, which are generally safe and well tolerated.

Exercise vs long sitting times: Will the beneficial effects of exercising on most days of the week neutralise all the unfavourable effects of time spent daily in the sitting posture? Studies reveal that all the health problems from prolonged sitting could not be attributed to lack of exercise alone. So it would be for our own good if we follow both good health practices - taking a half-hour brisk walk and spending more time in the upright posture.