SCMP Monday, May 29, 2000

Keeping Fit - incidental exercise


Obesity is becoming an epidemic. Recent statistics indicate 54.9 per cent of the American population and more than 50 per cent of Australians are overweight. From 1960 to 1994 in the United States the number of people in the obese category has increased by 10 per cent.

In Hong Kong, a Department of Health survey last year polled 3,270 people aged 18 to 64 following concerns over increasing obesity and other ailments. It found half of the respondents took no exercise and the least active were aged between 35 and 54.

From a layperson's point of view it appears quite evident that modern man, woman and child are eating too much and not exercising enough. But is it that simple?

It is true obesity is the inevitable consequence of an energy intake (calories consumed) that exceeds energy expenditure (calories used). What is interesting to note however is that today, people in industrialised countries consume approximately the same number of calories as they did 30 years ago, and the number of calories they expend during structured physical activity has actually increased slightly over the same period, thanks in no small part to the explosion of health clubs in these countries. In third world countries, where economies are labour intensive and the extent of labour required to maintain the GNP has not changed in the past 30 years, the prevalence of obesity is a fraction of that of developed countries. Herein, many researchers believe, lies the clue.

Structured physical activity, such as going to the gym, or playing a game of tennis, accounts for only a relatively small proportion of the total number of calories we can expend during a 24-hour period. With the advent of the technological age, our reliance on machines to do the dirty work, so to speak, has increased dramatically. Dishwashers, washing machines, TV remote controls, office intercoms, door to door transportation, escalators replacing stairs, even electric toothbrushes, are part and parcel of the modern day dictate to make life easier and more efficient. Consider then that efficiency by definition means a reduction in energy expenditure, and it becomes quite apparent our ever-increasing reliance on gadgets may well be making us fatter.

Incidental exercise is defined as the physical work we perform that could otherwise be performed by a machine. Spontaneous physical activity (SPA) is another term that refers to activity that need not be performed if we were to rely on a secretary, maid, or in the future maybe even a robot, to do it for us. SPA can be simply the act of getting out of the office chair and wandering to the next office instead of using the intercom, or walking to and from the bus stop instead of relying on a taxi or car (and let's be frank, the fewer people relying on their own cars for home to office travel, the better off we all will be).

Studies from Britain have demonstrated, if somewhat anecdotally, that the Briton of the 1990s expended as much as 600 calories per day less energy from incidental exercise than they did in the 70s. That is equivalent to a large hamburger and decent portion of French fries.

Modern technology has played its hand in other ways with children. The introduction of satellite and cable TV and the ubiquitous computer games mean children are now spending more time inertly glued to a box than ever before. Long gone are the days when children played ball in the park until it was too dark to continue. Long gone too are the days when children were full of energy, verging on the hyperactive. The link seems clear: inactivity breeds laziness, which breeds obesity.

The solution then is quite simple in theory. Although fighting the machinations of modernisation may be easier suggested in print than achieved in reality, the time to start the fight against obesity is now, before those aforementioned robots trundle languidly on the horizon.