Most of us assume that working out at the gym a couple of hours a week is enough to stay in shape and that going for a walk, jog or run every day or every second day keeps the body fit and reduces the threat of heart and circulation problems.
However, there is an alarming body of evidence that suggests that prolonged inactivity when sitting down at a desk, watching TV or playing video games, can be bad for you, even if you are active at other times.
Australian researchers conducted surveys of more than 220,0000 Australian adults aged 45 years and older, using questionnaires and census data.
They found that the greater the number of hours women and men spent sitting down continuously every day, the higher their risk of dying prematurely became. Those who sat for 8 hours had a 15 % extra risk of dying.
Surprisingly this risk was not affected by how active the subjects work. If subjects exercise vigorously every day the negative effects of sitting down for long periods of time were the same as for someone who had no regular exercise. The long periods of sitting down is itself appeared to be the problem.
There are a variety of approaches for avoiding this such as the standing desk, and encouraging staff to take regular exercise breaks to shorten the length of time spent sitting down continuously. This article reviews some of the other research, and discusses the notion of 'active sitting' which refers to ways you can remain active while sitting. For another article on the desk type cycling units for exercising while working.
Many previous studies have relied on questionnaires to get information on hours spent sitting down and activity levels and patterns, but these methods are known to be very unreliable. However a group of researchers from Finland developed the 'singing shorts' by embedding flexible electrodes into shorts and trousers fabric as a non-intrusive way of recording muscle activity in the legs.
Previous studies using animals that had their legs immobilized in various ways showed that there was a rapid and marked decrease in the levels of certain enzymes associated with blood sugar and fat metabolism. The study concluded that the lack of muscular activity in the legs led to changes in basic metabolism.
In the Finnish study, volunteers were required to wear the 'singing' shorts, and the muscle activity in the major leg muscles were recorded. The aim was to examine the relationship between activity and inactivity and whether the amount of time spent sitting was the same for those who exercised and those who did not. Surprisingly the results showed virtually no change in time spent sitting down between the active and inactive groups. During rest days, about 70 % of volunteers’ waking time, or about nine hours, was spent sitting. When the subjects exercised during the day, they expended about 15 % more energy in total than on days they didn’t exercise. However, despite this they still sat down about 70 % of the time throughout the day. So exercise did not change the amount of time spent sitting down being couch potatoes.
It seems that after exercising many people felt like relaxing. The conclusion from the study was that both active and inactive people shared that same risk of problems associated with sitting down for long periods of time. Of course, exercise is still very important as reduces risks for heart problems, cardiovascular disease and has many other benefits.
How to Reduce the Risks Associated with Sitting Down for Long periods of Time
There would appear to be three major approaches:
1. Frequent Regular Breaks - This would appear to be the best approach overall as it has been shown that getting up from your seat and walking around, even for 5-10 minutes every hour or so can be very beneficial - better still if the exercise is demanding such as climbing stairs or walking very quickly
2. Active Sitting - For those who cannot take regular mini-breaks the other option is active sitting - that is being active while you are sitting. This can involve various chair designed so that people sit forward and don't rest on the back of the chair and various cushion designs and seat arrangements so that the person sitting has to work to maintain their balance and position. This is not designed to be a permanent seating arrangement - but that is used for an hour or so at a time.
3. Stand-up Desks and Office Designs - These are aimed at reducing the amount of time people sit down when in the office by eliminating permanent desks, desktop computers, etc. and encouraging people to move around a lot more in the office.
Good posture when sitting down is very important. The first principle is to recognise that the tilt of your pelvis at the hips is critical for how the spine is curved or straight and the strain it places on the lower back. As shown in the diagram a vertical and upright pelvis places least strain on the spine and back. Tilting the pelvis backwards or forwards means that the spine must be curved to keep your back and head in an upright position. This causes strain on the back and can be very tiring. Slouching when siting can also lead to tiredness and back strain and cause long term back problems.
A common approach to active sitting is to intentionally make the sitting position unstable - not so you fall over, but so that you have to use various muscles to maintain your position. People are encouraged to sway slightly from side to side and from back to front to keep their muscles working. The simplest way to do this is by using an air filled sitting disc that may be built into the chair or be available as an air-filled cushion. This approach does not suit everyone and it does take some time to get used to it. Some people complain that it causes sore backs. However most people find it an excellent and easy way of keeping active when sitting down. Most people only use these methods for short periods of time - for an hour or so, and not for four to eight hours without a break.
Active sitting is therefore a style of sitting that allows your body to have a free and wide range of movements. The inherent minor instability means that dynamic muscular action in the core muscles are required to maintain an upright position., without using a back-rest. While most conventional sitting arrangement cause poor posture (with the back seldom vertical and encouraging a slouching posture), active sitting encourages good posture maintained dynamically.
There are many types of active sitting products available from exercise ball chairs, tilting chairs, and a variety of discs, pads and cushions that can be used on regular chairs. However, you can easily apply active sitting postures even without these devices. All you need to do is to sit up vertically straight and upright on the edge of your chair. Moving forward of the back-rest means you muscles have to work to keep you upright. Tilting the seat of the chair slightly forward.
Most people find it hard to sit for long periods of time (several hours) without back support, especially at first. But you need to be patient. Start slowly and increase the time spent using active sitting techniques over several months. This will eventually provide many benefits.
Conclusion: Reduce the time your spend inactively sitting down, and take regular breaks - it could well increase your life-span.