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Physical Activity and Obesity
Shirley Bryan, MKin and Peter Walsh, MSc (Health Canada)
Health Issue
Overweight and obesity have been recognized as a major public-health concern not
only in Canada but also throughout the world. Lack of physical activity, through its
impact on energy balance, has been identified as an important modifiable risk factor
for obesity. Physical activity and obesity are also important independent risk factors
for the development of many chronic diseases that affect women, placing a substantial
burden on the health care system. Despite this knowledge, the prevalence of obesity
continues to increase among women, and only a small portion of the female population
is active enough to achieve health benefits.
The aim of this chapter is to provide an overview of the current state of physical
activity and overweight/obesity among Canadian women. The health benefits of regular
physical activity are also briefly reviewed. Attention is paid to the individual and systemic
factors that determine women's adoption of regular physical activity throughout the
lifespan. A summary of the current Canadian recommendations for physical activity
and the World Health Organization recommendations for obesity prevention through
regular physical activity is also provided. A detailed interpretation of the 2000-2001
Canadian Community Health Survey provides prevalence rates for physical inactivity,
overweight, and obesity, with information presented in relation to gender, socio-economic
status, educational level, and cultural/racial origin. An analysis of trends is presented
where data are available.
Key Findings
- For all age groups combined, more women (57%) than men (50%) are physically inactive (expending < 1.5 kilocalories per kg per day). This sex disparity is greatest in the youngest and oldest age groups.
- Physical inactivity increases as income adequacy and educational level decrease, and this relation is stronger for women than for men.
- Physical inactivity varies by ethnicity. Among the least active are black women (76%) and South Asian women (73%).
- Between 1985 and 2000-2001, the prevalence of overweight (BMI 25.0.29.9 kg/m2) increased from 19% to 26% among women. It also increased among men during this period, but there has been a slight decrease in the prevalence of overweight over the last five years (from 44% in 1994-1995 to 40% in 2000-2001).
- Between 1985 and 2000-2001, the prevalence of obesity (BMI ³ 30 kg/m2) steadily increased, from 7% to 14% among women and from 6% to 16% among men.
- The prevalence of obesity among women increases with age, peaking between ages 55 and 59 and then decreasing steadily thereafter. This same pattern is seen in the male population, with the peak occurring in the 50-54 age group.
- The prevalence of obesity among women is highest in the low and lower-middle income groups, but the reverse is seen in the male population.
- The prevalence of obesity is highest among Aboriginal women (28%) and men (22%).
Data Gaps and Recommendations
The authors identified the following data gaps and made the following recommendations:
- There is a gap in the knowledge surrounding the socio-cultural and ecological determinants of physical activity for girls and women of various cultural backgrounds throughout the lifespan.
- Current knowledge on the relation between physical activity, obesity, and chronic disease has been derived from studies performed on predominantly Caucasian males. More research is needed to understand these relations among women and minority populations.
- Data/knowledge surrounding the indirect health care costs associated with physical inactivity and obesity are lacking.
- Multi-sectoral policy interventions (e.g. health, education, urban development, recreation, industry, transportation, etc.) that act to decrease the broad systemic barriers to physical activity and healthy weights among women are required.
- Integrated approaches using behaviour change as a model for lifestyle changes while addressing the issues related to supportive environments for women in various life stages are needed.
- Targeted interventions that aim to decrease the unique barriers of marginalized Canadians (e.g. women, lower-income groups, Aboriginal Canadians, older adults, and other special populations) should be developed.
- The importance of psychological determinants of physical inactivity and overweight/obesity need to be recognized and strategies developed to help women overcome them.
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