Physical activity intervention for males with high risk of coronary heart disease: a three-year follow-up

The Use of Behavioral Contracting to Increase Exercise Activity

A cardiovascular risk reduction program used a submaximal treadmill stress test to evaluate physical fitness. Of the 179 individuals who participated in the health education counseling activities which followed testing, 96 signed a behavioral contract to engage in a 12-week aerobic exercise program. Forty-one contractors fully met contract goals, and 21 reported increased activity levels. Analyses examined demographic, risk factor, and attitudinal predictors of contract signing and contract adherence. Contract signing was related to education, smoking, and women's mean body weight. Only women's body weight was related to contract adherence. Attitudes toward exercise were related to neither. Level of contract adherence was significantly related to a decrease in exercising heart rate at the six-month follow-up assessment. These data suggest that contract signing may be a useful device for assessing client motivation and predicting program participation and behavioral change outcomes.

Behavioral Contracting in an Urban Health Promotion Project

A health promotion project involving 223 participants was conducted by the Department of Family Medicine at Wayne State University in Detroit, Michigan. Participants were screenedforfive cardiovascular riskfactors: blood lipids, obesity, smoking, blood pressure and physical fitness; they were reassessed at six-month and two-year intervals. Following the initial screening, participants were asked to meet with the project health educator to sign one or more "behavioral contracts" to make behavior or life-style changes designed to improve risk factor status. Individual and group interventions were provided to all interested clients. Of the individuals screened, 179 of the 223 returned for at least one health counseling session. Contractors were most successful in improving exercise habits and making dietary changes to reduce cholesterol. These changes were reflected in improved treadmill performance and significant reductions in serum cholesterol. Smokers and the overweight showed poor success rates, few smokers were willing to sign a smoking cessation contract, and there was a high dropout ratefrom weightcontrol counseling.

A controlled trial of community based coronary rehabilitation

Two hundred patients who had suffered an acute myocardial infarction 4-6 weeks before entered a randomised controlled trial of exercise treatment at a community sports centre supervised by a general practitioner. Eighty one per cent of the treatment group continued to exercise until they returned to work and 73% completed three months' exercise. There were no serious complications of the exercise course. The prevalence of angina pectoris fell by 10% in the treatment group but rose by 60% in the control group. The perceived energy level rose by significantly more in the treatment group than in the controls. The rise in predicted maximum oxygen uptake was significantly greater in the treatment group than in the control group as was the reduction in the double product (a reflection of myocardial workload) at peak exercise. Coronary rehabilitation in the community can be both safe and effective.

Effects of physical activity on risk factors for coronary heart disease in previously sedentary women: a five-year longitudinal study

Fitness, weight, blood-pressure, and lipids were measured in 290 women joining a fitness programme. Five years later, 110 (38%) had remained active, and the others had become sedentary again. The net effect of being active was to increase fitness by 18% and to reduce weight by 1.9 kg, diastolic blood pressure by 3 mmHg, and triglycerides by 0.15 mmol/L-1. After controlling for age, weight and fitness, physical activity accounted for 1% and 3% of the variance of changes in systolic and diastolic blood pressure respectively, and was not associated with changes in lipids. Change in fitness accounted for only 1% of change in diastolic blood pressure. More 'active' women gave up smoking than 'inactive' (70% versus 10%). Hypertensive women were more sensitive to changes in weight and fitness than normotensive women. It was concluded that physical activity and change in fitness were only weakly related to changes in blood pressure and were unrelated to changes in lipids.

Smoking, alcohol consumption, and endurance capacity: an analysis of 6,500 19-year-old conscripts and 4,100 joggers

Using data from two Swiss studies, a 20% random sample (n = 6,592) of all 19-year-old army conscripts and all male participants in a 16-km popular race (n = 4,358), we studied the relationships among smoking, alcohol consumption, and endurance capacity using univariate and multivariate analyses. Alcohol was significantly correlated with endurance capacity among joggers in univariate analysis, but lost its significance in multivariate analysis. Among army conscripts, the distance covered in a 12-min endurance run was inversely related to daily cigarette consumption and years of smoking (P less than 0.001). This association was apparent even among light smokers who had been smoking for less than 2 years when they were compared with nonsmokers. Among joggers, even when the lower training activity of the smokers was controlled for, smoking retained a negative, independent association with endurance capacity, as measured by 16-km race time. In multiple regression analysis of endurance capacity, the standardized regression coefficient for smoking was -0.14 for distance covered in the 12-min run and 0.10 for 16-km running time, the latter despite the low prevalence (6.9%) of regular cigarette smokers among the joggers. Seventy percent of the 16-km race participants who smoked around the time they took up jogging quit smoking as joggers. Within the limits of this cross-sectional study design, these results suggest that smoking exerts a direct, biologically mediated, deleterious effect on endurance capacity. The lower levels of exercise of the smokers did not entirely explain the difference in endurance between smokers and nonsmokers. This observation of a short-term negative association between even light smoking and endurance capacity may have implications for health education and promotion efforts.

Vigorous physical activity and cardiovascular risk factors in young adults

There are conflicting data regarding the effects of vigorous physical activity (PA) and cardiovascular disease risk factors. Representative samples of adults aged 20-35 from four northern California cities were studied both cross-sectionally and longitudinally in order to examine the relationships between vigorous PA and selected physiological risk factors. A self-report measure of habitual vigorous PA was validated by pulse rate. There were relationships, in both cross-sectional and longitudinal analyses between self-reported vigorous PA and HDL/LDL ratio, especially for women. Relationships in cross-sectional analyses only were found between PA and diastolic blood pressure, total cholesterol, HDL-cholesterol, triglycerides, and alveolar carbon monoxide. The results of the present study generally tend to confirm investigations of other samples.

Exercise and the primary prevention of cardiovascular disease

Longitudinal population studies have consistently demonstrated an association between sedentary lifestyles and the incidence of coronary artery disease (CAD). Diverse lines of evidence from clinical and experimental studies further implicate physical inactivity as an important risk factor for CAD. The relation between physical inactivity and CAD appears to be curvilinear and independent of other major risk factors, but of lower magnitude. Several training-induced physiologic adaptations offer plausible mechanisms for the protective effects of physical activity. Extrapolation from available data indicates that exercise must be habitual, vigorous and continuous to provide protection from CAD. However, the observed association between inactivity and CAD could represent several hypotheses other than cause and effect. The need for an appropriately designed clinical trial is apparent, but such an endeavor is not feasible at present. Until more rigorous scientific data are available, judgment on the use of exercise in prevention of CAD must necessarily be based on the accumulation of evidence supporting the role of physical activity. The rationale for exercise in preventing the occurrence of CAD is reviewed.

Exercise for optimal health: strategies and motivational considerations

It appears that most people who engage in exercise for 20-60 min per day, 3 days per week, at an intensity level of 70-80% of maximal heart rate will derive at least some health-related benefits associated with improved cardiorespiratory fitness and optimal body weight. Individuals exhibiting extremely low cardiorespiratory fitness can probably derive benefits from even less exercise, while higher intensity and/or longer duration may be required to optimize some desired changes, particularly in areas associated with metabolic adaptation relative to blood lipids, diabetes, and psychological affect. While there is some evidence that it may take less exercise to maintain fitness levels already attained, a lifelong pattern of regular physical activity is recommended to optimize health-related benefits. Strategies which have been successful in combating high attrition rates in exercise programs include educational efforts to increase the participants' awareness pf exercise benefits; assessment procedures which determine the participants' needs, provide continuous motivational reinforcement, and accurately record improvement; and written contracts which hold participants accountable for reaching realistic goals within specified time periods.

Long-term effects of physical training programme on risk factors for coronary heart disease in otherwise sedentary men

Three hundred and seventy sedentary men aged 20-65 years enrolled in a physical training programme after a medical and fitness examination that included measurements of "classical" risk factors for coronary heart disease. Five years later re-examination showed (a) that on average the subjects had not changed significantly in weight, blood pressure, serum lipid concentrations, smoking habits, and physical working capacity; (b) that men who had remained active and therefore had a higher degree of fitness did not differ in risk factors from men who had returned to sedentary habits; and (c) that men who had improved substantially in fitness did not differ in risk factors from men whose fitness had not changed or had declined. Five years after the initial programme one-third of the men were continuing with regular vigorous exercise. These results do not support the view that classical risk factors for coronary heart disease improve with increased physical activity and fitness.