Prevalence of physical activity and sedentary behaviour

The estimates of activity levels of the population will partly be dependent on the method used. Similarly, the criteria defining the quantification of ‘activity’ will likely be inversely related to the activity levels reported. In other words, the more stringent the criterion adopted for classifying people as ‘active’, the fewer people will be classified as active. This accounts for why Stephens, Jacobs and White (1985), in their analysis of eight national leisure-time physical activity surveys, found that estimates of population physical activity levels varied from 15 per cent to 78 per cent. They concluded, however, that in North America approximately 20 per cent of the population take part in leisure-time physical activity of sufficient intensity and frequency that cardiovascular benefits are likely to result, while 40 per cent may be considered to be sedentary. The other 40 per cent would appear to be moderately or intermittently active with the possibility of some health benefits. An international analysis, however, shows that prevalence of ‘aerobic activity’ across Australia, Canada, England and the USA varies between 5 per cent and 15 per cent, whereas ‘moderate activity’ varies between 29 per cent and 51 per cent (including data from Finland). Similarly, estimates of sedentary adults in these countries varies from 43 per cent to 15 per cent (Stephens and Caspersen 1994). A pan-European study of adults showed that ‘inactivity’, defined as no leisure-time physical activity, was most prevalent in Portugal (60 per cent) and least so in Finland (8 per cent) (de Almeida et al. 1999). Surveillance of physical activity patterns usually shows that levels of activity are highest for males, for the young, and for those with higher educational/socio-economic status (de Almeida et al. 1999; Stephens and Caspersen 1994). In a summary of data from Canada, England, Finland, Germany and Sweden, Oja (1995) concluded that ‘health-enhancing physical activity’ varied from about 20 per cent in Sweden to nearly 50 per cent in Canada and England, with Finland at about 30 per cent. International recommendations now state that adults should seek to be active at moderate intensity for thirty minutes on most (at least five) days of the week (Department of Health 2004a; Pate et al. 1995). This means a target of 150 mins/week. According to de Almeida et al. (1999), many European countries have the majority of their adult population participating in more than 210 mins/week of leisure-time physical activity, with only Portugal and Spain below 50 per cent. However, most countries showed two extremes with many either doing very little or quite a lot of activity.