Sedentary behaviours include sitting time at work, at home, while commuting and during leisure time. During the last few decades, the rapid uptake of technology, high reliance on electronic communication, highly automated jobs and extensive international travels that came with globalisation along with an increase in the availability and use of televisions, computers, internet, social media, other online activities and games has led to an overall decrease in physical activity because individuals are spending more time in sedentary activities.
World Health Organisation (WHO) reported in 2014 that globally 1 in 4 adults do not meet the recommended levels of physical activity. If the global population were more active, up to 5 million deaths a year could be avoided -- a WHO approximate. People who are not adequately active have a 20-30 per cent elevated risk of death in contrast to people who are sufficiently active. More worryingly, WHO reported that greater than 80 per cent of the world's young population is now not adequately physically active.
Physical activity is defined as "any bodily movement produced by skeletal muscle and resulting in energy expenditure" and is commonly categorised as leisure time physical activity (LTPA) and non-leisure time physical activity (non-LTPA) by the US Centres for Disease Control and Prevention (CDC). LTPA is defined as physical activity performed during recreational time or at any other time not associated with one's occupation, housework, or transportation while non-LTPA are work related, household chores, and transportation related activities. The Physical Activity Guidelines for Americans by CDC indicated that regular physical activity improves health.
Physical activity varies with the type of job or occupation. Time at work typically represents a significant portion of a working age adult's daily activity and varies by the type of job and employment sector: about one third to one half of a day an adult may stay at work. Both LTPA and non-LTPA combined have a significant effect on a person's regular total caloric expenditure. However, one research study argued that the time spent in LTPA represents only a small portion of an individual's total activity time and indicated that non-LTPA has a greater impact on caloric expenditure.
Physical activity protects against gaining excess weight and developing its correlated disease conditions such as heart disease, diabetes mellitus (DM), breast and colon cancers etc. Obesity is acknowledged as a public health epidemic in many high-income countries and is a recognised as a major risk factor for cardiovascular diseases, diabetes mellitus (DM), depression, and cancer. These health conditions come with great human, social and economic costs. Obesity has been estimated to account for up to 3 per cent of a country's total health-care costs and medical costs of obese individuals are approximated as 30 per cent higher than individuals with normal weight.
Diabetes prevalence is known to vary by country as well as by region within a country-- a phenomenon partly credited to geographic differences in overweight and obesity prevalence, burden, and trends. The research literature indicates that physical inactivity, overweight, and obesity are modifiable risk factors for diabetes type 2 (DMT2) and regular physical activity leads to weight loss, increased insulin sensitivity, and improved glycemic control. The contribution of physical activity in DMT2 risk reduction is attributed to an improvement in insulin sensitivity and thus, a decrease in insulin resistance. It is believed that physical activity is the most important modifiable risk factor for improving the world's population health.
The Physical Activity Guidelines advised Americans to engage in at least 150 minutes/week of modest force aerobic exercise or 75 minutes of forceful activity / week in addition to the regular activities of daily living, such as grocery shopping, casual walking, or self-care to improve one's health. Research indicated that only 1 in 5 adults met the recommended physical activity guidelines in the U.S., and another study pointed out that only 1 in 3 of those trying to lose weight met the National Institutes of Health (NIH) exercise standards of 300 minutes a week. Alarmingly, physical inactivity has been identified by WHO as the fourth leading risk factor of worldwide mortality.
Additionally, research revealed that energy expenditure in occupation or job for both men and women has reduced by more than 100 calories/day, and this attribute to a considerable portion of the weight gain observed in the working age population in many countries. During the past few decades, physical activity realm has followed these general trends in the developed economies: 1) an increase in sedentary activity, 2) horizontal or slightly increased LTPA, 3) a decrease in household activity, transportation activity, work-related activity and 4) total physical activity. Things are not that different in Bangladesh particularly among its urban population and its white-collar workers.
During the last several decades several changes have been apparent in other countries: 1) high activity jobs have decreased, 2) low activity jobs have increased, 3) considerable decrease in housework activity has happened among women, 4) the average household has more vehicles than adult family members, and 5) a decline in walking and use of mass transit as a mean of transportation has occurred. Residents in Dhaka and other major cities may find some commonality with these patterns.
In terms of work-related activities, research confirmed that individuals in low status occupations and homemakers were less likely to participate in LTPA forceful enough to boost cardio-respiratory fitness. Likewise, studies in Australia and Finland found that blue-collar workers participate in less LTPA than white-collar workers. In terms of gender, women in blue-collar jobs were engaged in less physical activity than those in professional jobs.
In addition to the challenges posed by current technological developments, a growing body of research has confirmed the importance of the socio-environmental factors in the ability of a person to engage in physical activity. The obesity and chronic disease epidemics are closely knotted to changes in peoples' living and working environments and their sedentary lifestyle. Several other sources showed that in the US, obesity excessively affects minority population groups, in particular women and low socio-economic status people. Contrasted to wealthy neighbourhoods, low socio-economic status communities have fewer recreational amenities and physical facilities available, and when available they are found to be in a state of unusable or poor condition. To satisfactorily respond to the challenges posed by the low levels of physical activity, it is critical to comprehend the individual, social and environment level factors influencing that behaviour.
Physical inactivity has become an important cause of morbidity and mortality in high income countries, and its prevalence is also rapidly increasing in most low and middle income (LMIC) countries including Bangladesh particularly among its big city and upper socio-economic status population. The escalating prevalence of overweight and obesity in Bangladesh will place a high burden not only on its health care delivery system but also on its macro-economy.
Hasnat M Alamgir is Professor, Department of Pharmacy, East West University,
Dhaka, Bangladesh.