Habitual physical activity and cardiovascular risk factors

Demographic, clinical and lifestyle factors associated with high-intensity statin therapy in Australia: the AusDiab study

PURPOSE

Clinical guidelines specify who should receive high-intensity statins; however, it is unclear how high-intensity statins are used in Australia. Our objective was to determine the demographic, clinical, and lifestyle factors associated with high-intensity statin therapy in Australia.

METHODS

Data from the Australian Diabetes, Obesity and Lifestyle study collected in 2011-2012 were analyzed. High-, moderate-, and low-intensity statins were defined as use of statins at doses demonstrated to reduce low-density lipoprotein cholesterol levels by > 50, 30-50, and < 30%, respectively. Logistic regression was used to estimate adjusted odd ratios (ORs) and 95% confidence intervals (CIs) for factors associated with high- versus low-to-moderate-intensity statin therapy.

RESULTS

Overall, 1108 (24%) study participants used a statin. Data on statin intensity were available for 1072 participants. The proportions of high-, moderate-, and low-intensity statin therapy were 32 (n = 341), 65 (n = 696), and 3% (n = 35), respectively. Overall, 51% of people with prior cardiovascular disease (CVD) used a high-intensity statin. In addition to prior CVD (OR = 3.34, 95% CI = 1.95-5.73), no (OR = 1.84, 95%CI 1.02-3.31) or insufficient physical activity (OR = 1.51, 95% CI = 1.01-2.25), obesity (OR = 1.87, 95% CI = 1.13-3.10), and consuming > 2 alcoholic drinks daily (OR = 1.66, 95% CI = 1.08-2.55) were associated with high versus low-to-moderate-intensity statin therapy. Conversely, age 65-74 vs. < 65 years was inversely associated with high-intensity statin therapy (OR = 0.62, 95% CI = 0.41-0.94).

CONCLUSIONS

Prior CVD was the strongest factor associated with high-intensity statin therapy. Although the prevalence of CVD increases with age, older people were less likely to be treated with high-intensity statins.

Exercise and Obesity

This paper reviews succinctly the evidence for a role of regular exercise in the prevention and the treatment of obesity and of its metabolic complications. Seventeen propositions relevant to an understanding of the topic are considered. The evidence suggests that regular exercise can be an important factor in the development of sustained negative energy balance conditions provided the volume of activity is high. This implies a program of low to moderate intensity exercise performed on an almost daily basis for at least one hour per session. To induce significant weight and fat losses and to treat overweight and obese patients, compliance to the program for several years becomes a necessity. Exercise increases lipid substrate oxidation and may favor carbohydrate intake for the same amount of energy intake. The acute effects of exercise on resting metabolic rate are well documented, but the long-term influences of exercise training seem to be small and are rapidly suppressed with the cessation of training. The obese benefits also from a regular exercise regimen in terms of improved insulin sensitivity, lipid and lipoprotein profile, and blood pressure, as well as reduced risk of death. Regular exercise, such as walking, is a healthy course of action for the overweight or the obese patients.

31st g. Heiner sell lectureship: secondary medical consequences of spinal cord injury

Persons with spinal cord injury (SCI) have secondary medical consequences of paralysis and/or the consequences of extreme inactivity. The metabolic changes that result from reduced activity include insulin resistance with carbohydrate disorders and dyslipidemia. A higher prevalence of coronary artery calcification was found in persons with SCI than that in matched able-bodied controls. A depression in anabolic hormones, circulating testosterone and growth hormone, has been described. Adverse soft tissue body composition changes of increased adiposity and reduced skeletal muscle are appreciated. Immobilization is the cause for sublesional disuse osteoporosis with an associated increased risk of fragility fracture. Bowel dysmotility affects all segments of the gastrointestinal tract, with an interest in better defining and addressing gastroesophageal reflux disease and difficulty with evacuation. Developing and testing more effective approaches to cleanse the bowel for elective colonoscopy are being evaluated. The extent of respiratory dysfunction depends on the level and completeness of SCI. Individuals with higher spinal lesions have both restrictive and obstructive airway disease. Pharmacological approaches and expiratory muscle training are being studied as interventions to improve pulmonary function and cough strength with the objective of reducing pulmonary complications. Persons with spinal lesions above the 6th thoracic level lack both cardiac and peripheral vascular mechanisms to maintain blood pressure, and they are frequently hypotensive, with even worse hypotension with upright posture. Persistent and/or orthostatic hypotension may predispose those with SCI to cognitive impairments. The safety and efficacy of anti-hypotensive agents to normalize blood pressure in persons with higher level cord lesions is being investigated.

The potential metabolic consequences of cerebral palsy: inferences from the general population and persons with spinal cord injury

The metabolic consequences of cerebral palsy (CP) have not been reported. The observations and suggestions presented in this article are based on our current knowledge of physiology in the general population and on information on the known metabolic consequences of disability in persons with spinal cord injury. Because of pain, fatigue, and other secondary consequences of CP, adolescents with CP who are ambulatory may become less physically active with age. This phenomenon would be expected to be associated with deconditioning and adverse changes in body composition including atrophy of muscles and an absolute or relative increase in adiposity. Insulin resistance, hyperinsulinemia, and associated adverse metabolic changes may develop. In an unfavorable metabolic milieu, the ability of the pancreas to compensate for mild elevations of circulating glucose may diminish. The combination of reduced fitness and conventional risk factors for cardiovascular disease would be expected to increase the risk for coronary heart disease (CHD); however, there has been no assessment of the risk factors for CHD in adults with CP. Once subgroups with modifiable risk factors for cardiovascular disease have been identified, risk factors for CHD should be aggressively treated, according to current standards of care.

Coronary heart disease in individuals with spinal cord injury: assessment of risk factors

STUDY DESIGN

Discussion document.

OBJECTIVES/METHOD

To review the work performed on conditions and disorders that predispose persons with spinal cord injury (SCI) to an increased risk of coronary heart disease (CHD).

RESULTS/DISCUSSION

Individuals with SCI have an increased prevalence of abnormalities in carbohydrate and lipid metabolism because of immobilization, muscle atrophy and relative adiposity. In those with SCI, an inverse relationship has been reported between serum high-density lipoprotein (HDL) cholesterol values and abdominal circumference, and a direct relationship between serum triglycerides levels and abdominal circumference. Persons with SCI have lower serum HDL cholesterol levels than able-bodied controls. A higher prevalence of insulin resistance and diabetes mellitus, as well as an earlier occurrence of coronary heart disease (CHD), has been reported in persons with SCI than in the general population. Recently, a higher prevalence and greater degree of coronary artery calcification by electron beam computerized tomography has been demonstrated in persons with SCI, even if matched with the able-bodied population for age, gender, ethnicity and conventional risk factors for CHD. Knowledge of relative risk of CHD in persons with SCI is important for appropriate intervention strategies. The conventional risk factors for CHD were determined in veterans with SCI to assign risk to determine target low-density lipoprotein cholesterol levels for therapeutic intervention. Limitations of conventional guidelines when applied to the SCI population should be appreciated. Conventional risk factors for CHD should be identified and treated in individuals with SCI, according to current standards of care.

Relationship between blood pressure and physical activity assessed with stable isotopes

Intrapopulation and interpopulation variation in blood pressure (BP) often reflects the joint effect of a complex set of risk factors, including lifestyle factors such as physical activity, diet, smoking and alcohol use. In this study, we set out to quantify the impact of habitual levels of physical activity on BP within and between three populations at contrasting levels of population risk of hypertension. Individuals were randomly sampled from communities in Nigeria (n=57), Jamaica (from Kingston, n=35) and the United States (from the Chicago area, n=32). Activity energy expenditure (AEE) (estimated from resting energy expenditure measured by indirect calorimetry and total expenditure measured with doubly labelled water) was used as an objective estimate of physical activity. In each of the three samples, there was a consistent negative correlation between BP and AEE. This negative association persisted after adjustment for age, sex and body fat (body mass index or percent fat mass). In multivariate models, adiposity was no longer a significant predictor of BP after accounting for low AEE. In conclusion these data suggest that habitual levels of physical activity may have a generalizable relationship with BP in populations with widely different social and environmental characteristics.

Aerobic exercise and the post myocardial infarction patient: a review of the literature

Meta analyses of randomized controlled tests of cardiac rehabilitation after myocardial infarction demonstrate that regular exercise reduces the risk of overall mortality and cardiovascular mortality. In patients with established coronary artery disease, exercise is associated with improved activity tolerance, modification of risk factors, and improvement in quality of life. Randomized controlled tests demonstrate that whereas older patients after coronary events are substantially less fit than younger patients, they obtain a similar relative improvement of aerobic capacity with a graded conditioning program. However, older adults are enrolled in such programs at a lower rate than other age groups. Despite similar clinical profiles to men, women are less likely to participate in exercise rehabilitation. In this article we discuss the principles of program development, guidelines for monitoring of patients, and facilitation of exercise programs in the Australian context.

From exercise to physical activity

Recommendations for regular exercise have been evident in the nursing literature since the early 1900s. Health professionals and popular media have promoted vigorous exercise for positive health benefits since the 1960s. The concept of exercise as it appeared in the nursing literature during the early part of the 20th century is closer to the concept of physical activity of today--regular, moderate-intensity activities that become part of one's lifestyle. Nurses are in a unique position to counsel individuals, families, and communities on the importance of regular physical activity and to correct misconceptions that only vigorous exercise has health benefits.

Habitual physical activity, anabolic hormones, and potassium content of fat-free mass in postmenopausal women

BACKGROUND

Total body potassium (TBK) is known to decline throughout adulthood. The relations between physical activity, age, anabolic hormones, and TBK have rarely been considered.

OBJECTIVE

We sought to describe the relation between habitual physical activity, age, serum estradiol, and insulin-like growth factor I (IGF-I) and TBK in postmenopausal women.

DESIGN

TBK, fat-free mass (FFM), moderate-to-vigorous-intensity physical activity (MVPA; assessed with use of a semistructured interview), and serum concentrations of estradiol, IGF-I, and IGF binding protein 3 (IGFBP-3) were quantified in 51 healthy white women aged 54-76 y.

RESULTS

The potassium content of FFM declined curvilinearly with age, indicating an accelerated loss of skeletal muscle after 65 y of age. With the data split into high (n = 25) and low (n = 26) MVPA groups, the active women had 6.5% more potassium per FFM than did their less-active counterparts (P < 0.01). In multiple regression analysis, MVPA was the major determinant of the potassium content of FFM (P = 0.02), such that an active 70-y-old had the potassium content value of a 55-y-old sedentary woman. Serum estradiol, IGF-I, and IGFBP-3 were not significant determinants of the potassium content of FFM.

CONCLUSIONS

These data suggest that 1) habitual physical activity can significantly influence FFM potassium content; 2) physical activity must, therefore, be considered if the effect of aging per se on TBK is to be clarified; and 3) MVPA, such as that pursued by the active women in the present study (eg, walking, dancing, floor exercises, and swimming), can assist in preventing sarcopenia in older women.

Levantamento epidemiológico da prática de atividade física na cidade de São Paulo

Estudos epidemiológicos conduzidos em geral ou em populações específicas são de vital importância para a determinação e implementação de políticas públicas. Um dos problemas de saúde mais comuns que causa grande preocupação é o crescente número de pessoas obesas e, consequentemente, os problemas de saúde advindos da obesidade. No entanto, as desordens de sono, como a insônia, e distúrbios no ciclo vigília-sono que resultam de fatores psicológicos, neurológicos e sociais são também importantes problemas de saúde. Neste estudo, foi realizado um levantamento epidemiológico da prática de atividade física e problemas de sono na população geral da cidade de São Paulo. Mil indivíduos de todas a regiões da cidade, representando todas as classes sociais, responderam a um questionário específico. Os resultados mostraram que somente 31,3% dos entrevistados estão engajados em algum tipo de atividade física e somente 36,4% desses indivíduos têm supervisão de um profissional qualificado. Os distúrbios de sono associados com a insônia foram reportados por 27,1% dos indivíduos fisicamente ativos e 35,9% dos não ativos (p < 0,003). Dados de um estudo nacional em saúde e nutrição mostram um aumento na percentagem de indivíduos obesos no Brasil. Isto pode ser parcialmente explicado pelos nossos achados de baixos níveis de atividade física desta população pesquisada, o que pode levar a um aumento na incidência de doenças cardíacas e metabólicas (diabetes). Os resultados revelaram uma baixa percentagem de indivíduos engajados em atividade física regular sob supervisão da população em geral. Portanto, é importante alertar a população quanto aos benefícios da prática regular e supervisionada de exercícios físicos.

Leisure-time, occupational, and household physical activity among professional, skilled, and less-skilled workers and homemakers

BACKGROUND

Adults in lower status occupations are at higher risk of premature cardiovascular disease, for which physical inactivity is a major risk factor. While lower rates of leisure-time physical activity have been found to be associated consistently with lower income and education levels, the association between occupational and home-based physical activity with membership of different occupational categories is not well understood.

METHODS

An urban-representative population data set derived from a self-completion questionnaire was used to examine both self-reported leisure-time physical activity and a combined measure of occupational/home-based physical activity of adult less-skilled, skilled, and professional workers and homemakers (3795 males; 4140 females). chi(2) analyses, ANOVA, and logistic regressions were used to examine the associations between occupational group membership and physical activity.

RESULTS

After adjustment for age, body mass index, education, country of birth, marital status, and smoking, less-skilled workers were less likely to report any form of leisure-time physical activity. However, occupational category was not a strong predictor of participation in combined vigorous occupational/home physical activity. Homemakers and those in lower status occupations were less likely to report participation in vigorous leisure-time physical activity sufficient for cardiorespiratory fitness. With the inclusion of time spent in combined vigorous occupational/home physical activity, there was no longer an association of activity with occupational status for males. However, for females the association remained.

CONCLUSIONS

The assessment of occupational and household physical activity in addition to leisure-time activity may be important for understanding associations between occupational categories, physical activity, and increased levels of health risk and for the development of physical activity promotion strategies.

Physical activity of adult Australians: epidemiological evidence and potential strategies for health gain

Physical activity is now considered a major modifiable factor for preventing and reducing the mortality from cardiovascular disease, diabetes and some cancers, as well as improving musculoskeletal and mental health. Increasing epidemiological evidence confirms the health benefits of moderate regular physical activity. A dose response relationship remains, with greater benefits derived from increased intensity and duration of physical activity. Clinicians and exercise scientists should consider physical inactivity as important a risk factor as hypertension or elevated serum cholesterol levels. The broader public health objectives are to measure and monitor physical activity levels among all Australians, and to develop interventions to increase regular participation for the whole population. Population Campaigns and behaviour change programs are needed to increase the prevalence of participation in physical activity.

Aerobic fitness of Tasmanian secondary school children using the 20-m shuttle run test

The aim of this study was to determine the aerobic fitness of Tasmanian secondary school children aged 11 to 16 years. A random sample of Tasmanian secondary schools was undertaken and then all children within each grade in the school were tested. In all, 6061 children undertook the test, 2981 boys and 3080 girls. The test consisted of a 20-m shuttle run in time to a prerecorded timing sequence. Each child had to complete as many shuttles as possible while staying in time with the beep. The test ceased for each child when they could no longer reach the marker at the same time or prior to the generated sound. The analyses indicated that there was a significant main effect of grade and sex. Children in lower grades completed fewer shuttles than the children in higher grades, and boys completed more shuttles than girls within each grade. Students in government-run schools completed significantly fewer shuttles than their nongovernment school counterparts (p < .0001). On a regional basis, there were no differences between children in the north and south of Tasmania as each completed 5.7 +/- 0.1 shuttles but children in the northwestern region of the state completed a significantly greater number of shuttles. An estimation of mean VO2max based upon shuttle stages completed indicated that these values ranged from a low of 40.6 ml.kg-1.min-1 in 13-, 14-, and 15-yr-old girls to a high of 50.4 ml.kg-1.min.-1 in 16-yr-old boys. Comparisons between this and similar data suggest that Tasmanian school children are less fit than their counterparts around the world. In conclusion, normative data for Tasmanian school children were developed and distributed to schools throughout Tasmania for use by teachers in evaluating the fitness of their students.

Insufficiently active Australian college students: perceived personal, social, and environmental influences

BACKGROUND

A sustainable pattern of participation in physical activity is important in the maintenance of health and prevention of disease. College students are in transition from an active youth to a more sedentary adult behavior pattern.

METHODS

We assessed self-reported physical activity and other characteristics in a sample of 2,729 male and female students (median age was 20 years) recruited from representative courses and year levels at four Australian College campuses. They were categorized as sufficiently or insufficiently active, using estimates of energy expenditure (kcal/week) derived from self-reported physical activity. Personal factors (self-efficacy, job status, enjoyment), social factors (social support from family/friends), and environmental factors (awareness of facilities, gym membership) were also assessed.

RESULTS

Forty-seven percent of females and 32% of males were insufficiently active. For females, the significant independent predictors of being insufficiently active were lower social support from family and friends, lower enjoyment of activity, and not working. For males, predictors were lower social support from family and friends, lower enjoyment of activity, and being older.

CONCLUSIONS

Factors associated with physical activity participation (particularly social support from family and friends) can inform physical activity strategies directed at young adults in the college setting.

Relating physical activity to health status, social connections and community facilities

An important public health goal is to increase the population's participation in regular, moderate physical activity. Descriptive epidemiological studies that focus only on associations between physical activity and demographic and psychological factors are not sufficient to inform exercise promotion strategies, and a broader view of health is required. This study investigates the additional factors of health status, social connections and satisfaction with local area facilities by analysing data from a 1987 community health survey of 1765 residents of Adelaide. Factors associated with low activity were age group, education, general health (women), reduced mobility, number of social connections (men) and degree of satisfaction with recreation facilities. Including social and structural factors is valuable for research into interventions, policy and theory relating to physical activity as it brings theoretical perspectives and links to other areas of public health and social research.

The myth of "healthism" in organized sports: implications for health promotion sponsorship of sports and the arts

PURPOSE

The study examines the association of involvement in sports and arts with five health risk factors. The aims were to evaluate the argument that promotion of sports alone will achieve health objectives and to assess the suitability of sports and arts populations as targets for health promotion sponsorship.

DESIGN

Personal and telephone cross-sectional surveys were performed in Western Australia in 1992 (N = 2629) and 1994 (N = 2031).

SETTING

Sports and arts venues in Western Australia.

SUBJECTS

Random samples of household respondents aged 16 to 69 years.

MEASURES

Measures of association between risk factors and involvement in sports and the arts were adjusted for sex, age, residence, income, and other types of sports/arts involvement.

RESULTS

Spectators attending sports events, who were not members of organized sports clubs, were more likely to possess three or more risk factors than nonparticipants (OR = 1.43; 95% CI 1.20-1.70). They were more likely to report cigarette smoking, unsafe alcohol drinking, and poor sun protection practices. Sports club members had a similar profile of risk factors, except that their prevalence of smoking was reduced and they were much less likely to report inadequate physical exercise. The most elevated risk factor in sports populations was unsafe alcohol drinking (OR = 1.81 in club members, 1.88 in spectators, and 2.25 in spectators who were also members). Arts populations were less likely than average to report elevated risk factors, especially in the case of members of arts organizations who also attended arts events (for three or more risk factors, OR = 0.59; 95% CI .45-.75). However, the majority of arts respondents had at least two risk factors. Levels of inadequate exercise in arts populations were the same as those in sports populations.

CONCLUSIONS

The promotion of sports alone is unlikely to achieve health objectives. Highest priority in the use of health promotion sponsorship funds should be given to the populations attending sports events and involved as members of sports clubs. Investment in arts sponsorship is warranted, but at a lower level than health sponsorship of sports.

Relationship between a 14-day recall measure of leisure-time physical activity and a submaximal test of physical work capacity in a population sample of Australian adults

This paper reports on the validity of a 14-day recall measure of leisure time physical activity (LTPA) in a sample of Australian adults (N = 986). Submaximal cycle ergometry was used to assess physical work capacity per kilogram of body mass (pwc75/kg). The self-report energy expenditure estimates were used to categorize respondents as vigorously active, moderately active, and low active/sedentary. Multiple regression analyses showed that pwc75/kg increased significantly across energy expenditure categories for adults aged less than 40 years; that the vigorous and moderate activity categories had greater mean pwc75/kg values than the low/sedentary category for 40 to 59-year-olds; and, that there were no differences in pwc75/kg between activity categories for those aged 60 years or older.

Plasma cholesterol and other cardiac risk factors in adolescent girls

The aim was to examine the effects of smoking, physical activity, and body mass on total cholesterol and high density lipoprotein cholesterol (HDL-C) in adolescent schoolgirls in Sydney, Australia. Body mass index (BMI) and waist to hip ratio (WHR) were determined in 144 girls aged 15 to 18 years. Total cholesterol (TC) and HDL-C were estimated on fingerprick blood and behavioural variables assessed by questionnaire. Prevalence of overweight (> 90th centile for BMI) was less in Australian adolescents than reported from the USA. Smokers had lower total cholesterol than non-smokers; this was partly explained by a lower HDL-C in the smokers. Physical activity was associated with a less atherogenic TC/HDL-C ratio. Girls with BMI > 90th centile had higher mean TC/HDL-C and apoprotein B than the group as a whole but those > 90th centile for WHR did not.

Cost-effectiveness of alternative interventions for the prevention and treatment of coronary heart disease

Although mortality from coronary heart disease (CHD) in Australia has fallen dramatically since the 1960s, it still remains the major cause of death in Australia and poses a significant burden on the economy. Even though a number of studies have concluded that prevention has been the main determinant of the declines in CHD, a disproportionate amount of health-care expenditure is devoted to treatment rather than prevention. This paper reviews the international literature on the economic appraisal (costs and benefits) of alternative interventions for the treatment and prevention of CHD with the view of assessing whether there is sufficient evidence to justify a reallocation of resources away from treatment to prevention. First, few studies on the economic evaluation of CHD prevention and treatment programs have been undertaken in Australia, with most being from the United States and Europe. Second, assumptions about the specification, measurement and valuation of costs, and the epidemiological evidence on program effectiveness have varied. Third, health promotion and prevention programs are not necessarily more cost-effective than drug or surgical treatments for CHD. Individual interventions must be judged on their own merits. There is a need for a systematic evaluation of interventions for CHD using primary Australian data to better inform decision making on resource-allocation priorities. Such an evaluation should incorporate economic evaluation techniques.

Serial mass-media campaigns to promote physical activity: reinforcing or redundant?

Changes associated with two serial, nationwide, mass-media-based campaigns to promote physical activity conducted by the National Heart Foundation of Australia in 1990 and 1991 were examined. Surveys conducted before and after each campaign found statistically significant differences in message awareness (46% vs 71% in 1990; 63% vs 74% in 1991). In 1990, there were significant increases in walking, particularly among older people, and in intentions to exercise. No such changes were apparent in 1991. In the case of these two campaigns, conducted 1 year apart, the second may have been redundant.

Leisure-time physical activity and other health behaviours: are they related?

Data on the associations between leisure-time physical activity and other health behaviours are conflicting. The National Heart Foundation 1989 Risk Factor Prevalence Survey data were analysed to examine the associations between leisure-time physical activity and other life-style health behaviours in a national representative sample with adjustment for potential confounders. Multivariate stepwise logistic regression analysis using data from 9054 respondents aged 20 to 69 years showed that participation in leisure-time physical activity, even when it was not vigorous, was weakly associated with not smoking, following a special diet and moderate consumption of alcohol; it was inversely associated with obesity. These weak associations could influence health practices at a population level if, as has been hypothesised, the adoption of leisure activity promotes the adoption of other good health practices. Confirmation of earlier findings of cross-sectional associations between activity and other positive health practices justifies future prospective or experimental studies to determine the behavioural response to adoption of leisure-time physical activity.

Exercise and dietary modification with women of non-english speaking background: A pilot study with polish-australian women

Health promotion programs aimed at the general community often fail to reach Australians of non-English speaking background (NESB) because of language and cultural barriers. A 12-week minimal-intervention heart health program, designed for women of European background, was piloted with 43 women from a Polish social group, with a further 30 women serving as a comparison group. Assessments of the intervention group before and after the 12-week program indicated significant decreases in exercising heart rate and in resting blood pressure, which were not evident in the comparison group. Twelve-week follow-up data indicated that these gains had been well maintained. When the comparison group was invited to participate in a similar program, there were also significant improvements on these variables. This pilot study suggests that health promotion programs aimed at NESB Australians can be effective in modifying risk factors for cardiovascular disease if an effort is made lo address language and cultural barriers.

A descriptive epidemiology of physical activity from a Northern Ireland perspective

The benefits of physical activity are well documented and exercise is included in most health promotion recommendations but, before adopting a population strategy, it is important to establish baseline patterns of physical activity so as to make regional and international comparisons and measure behaviour change. This review examines adult physical activity participation in a national and international context and highlights how difficult it is to draw meaningful conclusions and detect trends from studies that measure physical activity using different measuring instruments. Overall, about 4 in 5 people are active at least occasionally but the more rigorous the definition of habitual physical activity the lower the participation rates so that less than 1 in 5 people perform regular vigorous physical activity. Males are more active than females with a decrease in physical activity with increasing age. There is a social class gradient with those in social classes 1 and 2 being more active.

Population prevalence and correlates of stages of change in physical activity

Stages of change for exercise, sociodemographic variables, and beliefs about the health benefits of exercise were obtained for a representative sample of Australian adults (N = 4404). Logistic regression analysis was used to examine the relationship between exercise stage of change and sociodemographic variables and beliefs about the benefits of exercise. Thirteen percent of respondents stated that they did not exercise and did not intend to start; 10% stated that they did not exercise but were thinking of starting; 16% stated that they exercise occasionally and were not thinking of doing more; 23% stated that they exercised occasionally and were thinking of doing more; and 38% stated that they exercised regularly and intended to continue. Intention to do more exercise generally decreased with increasing age, but increased with level of education. An increased frequency of exercise and an intention to do more exercise was associated with the belief that exercise would help to prevent heart disease and with a higher level of education. The results provide a useful profile of the exercise habits (and intention to change those habits) of population subgroups. Public communication campaigns on the benefits of physical activity should focus particularly on those who do not intend to exercise, older adults, and the less well educated.

The definition and assessment of physical activity in cardiovascular risk reduction research

Community-wide promotion of physical activity is becoming increasingly relevant in the development of social, economic, and health-related policy. Such research raises issues in the assessment of physical activity on a population basis. This paper reviews definitions of physical activity for cardiovascular risk reduction and the assessment techniques which arise from them, and makes some recommendations, firstly for the identification of appropriate levels of physical activity, and secondly for the development and selection of assessment techniques. It seems that a clearer conception of appropriate activity levels for fitness and for health will require further research with a range of population groups and activity types. Greater standardisation of questionnaires, improved validity of measures, and a greater understanding of possible response biases will also improve the quality of the basic information on which interventions and policies are developed.