Exercise and the primary prevention of cardiovascular disease

Association of Physical Activity With Primary Cardiac Arrest Risk in the General Population: A Nationwide Cohort Study of the Dose-Response Relationship

OBJECTIVE

To quantify the dose-response relationship between moderate to vigorous physical activity and primary cardiac arrest (PCA).

PATIENTS AND METHODS

There were 504,840 participants older than 18 years who underwent the Korean National Health Screening Program, including a self-administered questionnaire for physical activity from January 1, 2009, through December 31, 2014. Physical activity levels were converted into metabolic equivalent tasks (METs) per week and categorized to correspond with multiples of public health recommendations. We evaluated the quantitative and categorical dose-response relationship between physical activity and PCA.

RESULTS

A curvilinear dose-response relationship between physical activity and PCA was observed; the benefits started at two-thirds (5 MET-hour/week) of the United States and World Health Organization guidelines-recommended minimum (7.5 MET-hour/week) and continued to 5 times (40 MET-hour/week) the recommended minimum (P nonlinearity <.001). The largest benefit was noted at a level of 2 to 3 times the recommended minimum (hazard ratio, 0.6; 95% CI, 0.4 to 0.8). In addition, there was no evidence of an increased PCA risk at a level more than 5 times the recommended minimum (hazard ratio, 0.7; 95% CI, 0.5 to 1.1). These associations were consistent regardless of age, sex, body mass index, comorbid conditions, and estimated 10-year risk for cardiovascular disease.

CONCLUSION

The beneficial effect of physical activity on PCA started at two-thirds of the recommended minimum and continued to 5 times the recommended minimum. No excess risk for PCA was present among individuals with activity levels more than 5 times the recommended minimum regardless of cardiovascular disease or lifestyle risk factor presence.

Why Does Exercise "Trigger" Adaptive Protective Responses in the Heart?

Numerous epidemiological studies suggest that individuals who exercise have decreased cardiac morbidity and mortality. Pre-clinical studies in animal models also find clear cardioprotective phenotypes in animals that exercise, specifically characterized by lower myocardial infarction and arrhythmia. Despite the clear benefits, the underlying cellular and molecular mechanisms that are responsible for exercise preconditioning are not fully understood. In particular, the adaptive signaling events that occur during exercise to "trigger" cardioprotection represent emerging paradigms. In this review, we discuss recent studies that have identified several different factors that appear to initiate exercise preconditioning. We summarize the evidence for and against specific cellular factors in triggering exercise adaptations and identify areas for future study.

Design and Rationale for a Randomized Controlled Trial Testing the Efficacy of Aerobic Exercise for Patients with Obsessive-Compulsive Disorder

BACKGROUND: Over the last two decades very few advances have been made in the development of new treatments for obsessive-compulsive disorder (OCD). While patients with OCD improve with available treatments (pharmacotherapy and/or cognitive-behavioral therapy), moderate levels of OCD symptoms often persist even with adequate doses and durations of these treatments. Building on the growing body of evidence for the efficacy of exercise in the treatment of other psychiatric disorders, interventions to increase aerobic exercise in patients with OCD represent a potentially useful yet relatively unexplored strategy in OCD. METHODS/DESIGN: One hundred and two (102) patients with clinically significant OCD symptoms despite current engagement in recommended treatments (pharmacotherapy and/or CBT) will be randomly assigned to receive either a 12-week moderate intensity aerobic exercise (AE) intervention or a health education control (HEC) intervention. Follow-up interviews will be conducted at the end of treatment and at 3-, 6- and 12-months post-intervention. They will assess OCD severity, nonspecific anxiety, depression, quality of life, cardiorespiratory fitness and cognition (executive function). DISCUSSION: If efficacy is established, patients with OCD who have clinically significant residual symptoms despite current pharmacotherapy or CBT would gain a valuable and practical treatment augmentation option.

Aerobic exercise for alcohol recovery: rationale, program description, and preliminary findings

Alcohol use disorders are a major public health concern. Despite the demonstrated efficacy of a number of different treatments for alcohol dependence, relapse remains a major problem. Healthy lifestyle changes may contribute to long-term maintenance of recovery, and interventions targeting physical activity, in particular, may be especially valuable as an adjunct to alcohol treatment. In this article, the authors discuss the rationale and review potential mechanisms of action whereby exercise might benefit alcohol dependent patients in recovery. They then describe the development of a 12-week moderate-intensity aerobic exercise program as an adjunctive intervention for alcohol dependent patients in recovery. Preliminary data from a pilot study (N=19) are presented, and the overall significance of this research effort is discussed.

Are parental health habits transmitted to their children? An eight year longitudinal study of physical activity in adolescents and their parents

Parents are believed to play a role in influencing their children's health behaviours. This longitudinal study of two generations (parents and their children) examined associations between parents' self-reported leisure-time physical activity changes and the self-reported physical activity changes of their offspring in a sample of 557 adolescents over an 8 year period (from 13 to 21 years of age). The results revealed only weak and non-existent associations between changes in parents' physical activity and changes in adolescent physical activity from 13 to 21 years of age. The findings did not support the hypothesis that adolescents' leisure-time physical activity covaried with their parents' leisure-time physical activity over time. This may mean that parental physical activity is not transmitted to their children to the degree that is often believed.

Cardiovascular risk factors, monitoring, and therapy for HIV-infected patients

Cardiovascular complications are important contributors to morbidity and mortality in HIV-infected patients. These complications can usually be detected at subclinical levels with monitoring, which can help guide targeted interventions. This article reviews available data on types and frequency of cardiovascular manifestations in HIV-infected patients and proposes monitoring strategies aimed at early subclinical detection. In particular, we recommend routine echocardiography for HIV-infected patients, even those with no evidence of cardiovascular disease. We also review preventive and therapeutic cardiovascular interventions. For procedures that have not been studied in HIV-infected patients, we extrapolate from evidence-based guidelines for the general population.

Cardiovascular monitoring and therapy for HIV-infected patients

Cardiovascular complications are important contributors to morbidity and mortality in HIV-infected patients. These complications can usually be detected at subclinical levels with monitoring, which can help guide targeted interventions. This article reviews available data on types and frequency of cardiovascular manifestations in HIV+ patients and proposes monitoring strategies aimed at early subclinical detection. In particular, we recommend routine echocardiography for HIV+ patients, even those with no evidence of cardiovascular disease. We also review preventive and therapeutic cardiovascular interventions. For procedures that have not been studied in HIV+ patients, we extrapolate from evidence-based guidelines for the general population.

A cardiovascular health needs assessment of university students living in residence

The purpose of this study was to determine the cardiovascular health needs of university students living in residence. A survey was administered to students living in residence at a university in Nova Scotia, Canada to identify eating patterns, physical activity, smoking behaviours and perceived stress. Data were analyzed using descriptive statistics and chi-square tests of association. Qualitative data were collected using focus group interviews. Results showed that fewer than half of the students participated in exercise three or more times per week, and 82% are less than the recommended amount of fruits and vegetables. As perceived knowledge of CVD increased so did level of physical activity and consumption of fruits and vegetables. Fifty-six percent of students rated their stress as high or very high; exams and course assignments are a major cause of this stress. Fifteen percent of the university students surveyed were daily smokers. Barriers to a healthy lifestyle include time constraints and limited food choices in the residence cafeteria.

Regular physical activity and coronary risk factors in Japanese men

BACKGROUND

Physical activity decreases the risk of coronary heart disease (CHD), but its effects on risk factors require further exploration.

METHODS AND RESULTS

The study included 3331 adult Japanese men in whom health benefits, especially CHD risk factors, were compared among those who were sedentary and those who were engaged in continuous physical activity of 30 minutes or more per day for 1, 2 and > or =3 days per week. Significantly higher HDL cholesterol values; lower triceps, scapula, and iliac subcutaneous fat thickness; and lower smoking rates were noted in all physically active groups compared with the sedentary group, whereas body mass index did not differ significantly. Waist-to-height ratios and the prevalence of fatty liver were significantly lower in the groups who exercised 2 or > or =3 days per week than in the sedentary group. The lowest triglyceride values were noted in the group who exercised > or =3 days per week. Multiple regression analysis revealed both the frequency of physical activity and smoking status to be independent positive and negative factors, respectively, for the HDL cholesterol value. The sum of the risk factor scores for hypertension, abnormal glucose tolerance, hypertriglyceridemia, hypercholesterolemia, and low HDL cholesterol level (one point for each if present) was highest in the sedentary group (1.38, 1.19, 1.19, 0.99 for the sedentary group and the groups who exercised 1, 2, and > or =3 days per week).

CONCLUSIONS

Those who engaged in regular physical activity > or =3 days per week appeared to have the fewest coronary risk factors. However, even those engaged in physical activity once per week had fewer CHD risk factors than sedentary individuals.

Condicionamento físico aplicado a doenças cardiovasculares

Tendo em vista a relevância da prevenção das doenças cardiovasculares, este artigo visa discutir alguns aspectos relativos à prevenção cardíaca primária e secundária a partir de um programa de condicionamento físico especializado. A prática da atividade física regular é utilizada tanto para a prevenção como para a reabilitação das doenças cardiovasculares. Um bom programa de condicionamento físico produz alterações fisiológicas crônicas nos sistemas cardiovascular e neurovegetativo e na secreção hormonal, constituindo expressivas modificações no que diz respeito à prevenção, estabilização e até regressão do quadro degenerativo das cardiopatias. A supervisão do paciente durante a sessão de condicionamento físico é essencial, pois a incidência de complicações cardiovasculares é maior nestes, quando comparados com adultos aparentemente saudáveis; com isso, a segurança e a qualidade do programa ficam salvaguardadas. Um aspecto muito importante é a necessidade da prescrição de exercício individualizada, tanto na prevenção primária como nas três fases de prevenção secundária. Essa prescrição deve respeitar os princípios do treinamento físico e os componentes básicos do programa: freqüência e duração, que são valores absolutos, e a intensidade, que é o fator crítico da prescrição, pois é relativa e envolve fatores como diferença entre os sexos, nível de aptidão física e idade

Systemic arterial blood pressure responses of stroke-prone spontaneously hypertensive rats to treadmill exercise

The present study was undertaken to compare the systemic blood pressure responses during graded acute exercise of stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto rats (WKY). Systemic blood pressure was measured by left carotid artery catheter during exercise. Systolic blood pressure incre-ments with running exercises at 10, 15, and 20 m/min were significantly greater in SHRSP than in WKY. Diastolic blood pressure increments with exercise were singnificantly greater only at 20 m/min in SHRSP compared to WKY. This study suggests that the blood pressure response to exercise is accentuated in SHRSP.

Non-pharmacological modification of cardiac risk factors: Part 1

Many factors influence whether a person will develop coronary heart disease. Genetic predisposition, gender and advanced age are recognized risk factors for the development of coronary heart disease over which we have little control. On the other hand, high serum cholesterol, cigarette smoking, high blood pressure, excessive body weight and long-term physical inactivity are key risk factors over which we have considerable control. In many cases cardiac risk factors can be modified without resorting to pharmacological intervention. Current evidence suggests that individuals who follow a diet which is low in saturated fats and cholesterol, lose weight, stop cigarette smoking and take regular aerobic exercise will significantly reduce their risk of developing coronary heart disease. In addition, patients who already have evidence of coronary heart disease may improve their symptoms and prognosis by similar life-style changes. In the first of two parts, we review the role of exercise in modifying cardiac risk factors.

Physical activity and 23-year incidence of coronary heart disease morbidity and mortality among middle-aged men. The Honolulu Heart Program

BACKGROUND

The purpose of the study was to examine the association between physical activity and 23-year incidence of coronary heart disease morbidity and mortality. This cohort study continues to follow 8006 Japanese-American men who were 45 to 68 years of age and living on Oahu, Hawaii, in 1965, for the development of coronary heart disease morbidity and mortality.

METHODS AND RESULTS

The Framingham physical activity index was calculated by summing the product of average hours spent at each activity level and a weighting factor based on oxygen consumption. Study subjects were divided into tertiles of physical activity index at baseline. Relative risks and 95% confidence intervals (CI) for incidence of coronary heart disease morbidity and mortality were obtained using the Cox model. After age adjustment and using the lowest physical activity index tertile as a reference group, the relative risk for coronary heart disease incidence for the highest tertile of physical activity was 0.83 (CI, 0.70 to 0.99). After adjusting for age, hypertension, smoking, alcohol intake, diabetes, cholesterol, and body mass index, the relative risk was 0.95 and CI included 1 (CI, 0.80 to 1.14). For coronary heart disease mortality, the age-adjusted relative risk was 0.74 (CI, 0.56 to 0.97) and 0.85 (CI, 0.65 to 1.13) after risk factor adjustment.

CONCLUSIONS

The results suggest that the impact of physical activity index on coronary heart disease is mediated through its effects on hypertension, diabetes, cholesterol, and body mass index. These findings support the hypothesis that physical activity is inversely associated with coronary heart disease morbidity and mortality and suggest that physical activity interventions in middle-aged men, by improving cardiovascular risk factor levels, may have significant public health implications in the prevention of coronary heart disease.

Physical conditioning can modulate endothelium-dependent vasorelaxation in rabbits

To investigate whether exercise training can modulate endothelium-dependent vasorelaxation, male New Zealand White rabbits were divided into either control or training groups. The training animals were trained on a treadmill with a running speed of 0.88 km/hr on a 0 degree grade for 10-60 minutes/day, 5 days/week for 8 weeks. After exercise training, the resting heart rate was lowered (p < 0.05). At the end of the experiments, three vessel segments, i.e., the thoracic aortas, the pulmonary arteries, and the common carotid arteries, were isolated and precontracted with norepinephrine. Acetylcholine-stimulated endothelium-derived relaxing factor (EDRF) release was assessed by bioassay in the presence of indomethacin (10(-5) M). Basal release of EDRF was examined by the addition of hemoglobin. In addition, the relaxing responses of the thoracic aortas and pulmonary arteries to A23187, a calcium ionophore, and to sodium nitroprusside, a direct vasodilator of vascular smooth muscle, were compared between control and trained groups to further investigate possible underlying mechanisms. The results indicated that after exercise training 1) both the thoracic aorta and pulmonary artery, but not the carotid artery, became more sensitive to acetylcholine-induced vasorelaxation; 2) no significant differences in basal release of EDRF between control and trained rabbits were observed; and 3) there were no significant differences in the vascular responses to A23187 or sodium nitroprusside between the two groups. Our data suggest that exercise training may enhance endothelium-dependent vasodilation to acetylcholine via the stimulated EDRF release and that this elevated sensitivity to acetylcholine may not be caused by the alteration of the relaxing response in vascular smooth muscle.

Personal determinants of leisure-time exercise activities

This study investigated the importance of personal determinants such as self-efficacy, beliefs about the contribution of exercise, health locus of control, and dispositional optimism for leisure-time exercise in a working population. The main predictors of such exercise were beliefs and self-efficacy with the generalization of the latter to eat correctly. Beliefs and efficacy expectations were highly correlated. Neither health locus of control nor dispositional optimism was related to leisure-time exercise; however, optimism was related to the positive belief that exercise contributes to health. Ramifications of the findings were carefully described.

Effect of a six-month aerobic exercise training program on cardiovascular responsivity in healthy middle-aged adults

The purpose of this study was to determine the effects of a six month aerobic exercise training regimen on cardiovascular responsivity to mental arithmetic in healthy middle-aged men and women. Subjects were randomly assigned to a moderate intensity exercise intervention or to an assessment-only control group. Before and after the intervention subjects' heart rates and blood pressures were measured doing a mental arithmetic task (N = 83). Other physiological and psychosocial measures included the Type A structured interview and a maximal exercise treadmill test. Validated adherence to the exercise regimen exceeded 75% and there were significant increases in aerobic capacity in those subjects receiving exercise training. Exercise did not significantly reduce cardiovascular responsivity to the stress task. Type A behavior did not interact with reactivity across exercisers or controls nor was it significantly correlated with adherence. The results are discussed with respect to factors that have been previously reported to potentially influence the exercise/reactivity relationship.

Exercise as a coronary protective factor

Exercise has multiple beneficial actions, both in normal subjects and in patients with coronary artery disease, which can be cardioprotective. Apart from reducing known risk factors and protecting against their deleterious effects, exercise also reduces the risk of coronary artery disease by increasing cardiovascular fitness. The exact contribution of each of these mechanisms in reducing coronary artery disease morbidity and mortality is unclear. Although fitness may be desirable, much of the cardioprotection can be achieved through increased leisure time and recreational physical activity. The risk-benefit ratio is very much in favor of moderate intensity exercise. Even in the absence of a controlled trial, the available evidence suggests that efforts to encourage physical activity are justified.

What is the dose-response relationship between exercise training and blood pressure?

Most studies of exercise and blood pressure have used a standard exercise programme with a single level of physical activity. To determine the nature of the dose-response relationship however it is necessary to examine several levels of activity, preferably in the same subjects. We have recently performed several randomised crossover studies comparing different levels of regular exercise. The intensity and duration of exercise bouts were constant throughout the studies, but their frequency was varied. Standard bouts consisted of 30 min of bicycling at 60%-70% of maximum work capacity. The exercise was performed either three-weekly or 7-weekly in randomised order and each level was maintained for one month. In sedentary normal subjects three bouts of exercise/week for a total of 90 min lowered blood pressure by 10/7 mmHg. With seven bouts, i.e. a total of 210 min exercise/week, blood pressure was only slightly lower than 3-week exercise and was 12/7 mmHg below sedentary values. Responses to measures of physical fitness including maximum oxygen consumption and work capacity were linearly related to the amount of exercise performed each week. Similar results were obtained in hypertensives. Another randomised study was performed amongst expeditioners to Antarctica where environmental conditions determined that they were sedentary in winter and active in summer. The addition of either 3-week or 7-week exercise in winter significantly lowered blood pressure. In summer when the background level of activity was higher, blood pressure with no added exercise was similar to exercising levels in winter. There was no further fall in blood pressure with either 3-week or 7-week additional exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Stroke volume during submaximal exercise in endurance-trained normotensive subjects and in untrained hypertensive subjects with beta blockade (propranolol and pindolol)

The effect of beta-adrenergic blockade on stroke volume (SV) at increasing submaximal exercise intensities was studied in 12 endurance-trained normotensive and 12 untrained hypertensive (diastolic blood pressure greater than 95 mm Hg) men, aged 18 to 34 years. Subjects were assigned to each of 3 treatments in a double-blind, randomized order: placebo, propranolol (80 mg twice daily) and pindolol (10 mg twice daily) for 10 days, with a period of 48 to 60 hours from the initial dose to the first treadmill test and a 4-day washout period between drugs. Cardiac output was measured using the carbon dioxide rebreathing method and SV was calculated from cardiac output and heart rate as follows: SV = cardiac output/heart rate. Cardiac outputs were estimated at rest and while walking on a treadmill at 25, 45, 60 and 75% of the subject's previously determined maximal oxygen uptake (VO2max). No significant differences were found in cardiac output between either of the drugs and placebo at rest, or at any of the 4 rates of work. Propranolol significantly increased SV above placebo values (p less than 0.05) for both trained and untrained groups at the intensities of 45, 60 and 75%. Significant differences in SV were found between pindolol and placebo only at the intensities of 60 and 75% in the trained group. Contrary to expectations, SV showed no indication of a plateau with propranolol in the trained subjects throughout the 4 different exercise intensities, whereas a plateau was established under placebo conditions by 45% of VO2max in both trained and untrained subjects. These results suggest that both trained and untrained hypertensive persons can exercise with beta-adrenergic blockade at submaximal levels without compromised cardiac function.

Habitual physical activity and cardiovascular risk factors

The relationships between different levels of participation in physical activity and biological indices of cardiovascular risk were examined in a sample of 6814 male and female adults who took part in a national risk factor prevalence survey. Participation in physical activity was classified as "aerobic" (14.6% of total), "moderate" (53.6%) or "inactive" (31.8%). Bivariate analyses found significant associations between level of exercise participation and diastolic blood pressures in men, but not in women; significant associations were found between reported physical activity and systolic blood pressure, total serum cholesterol, high-density lipoprotein (HDL) cholesterol, HDL/total cholesterol ratio and triglycerides for both men and women. Further analyses were controlled for age, education, and the survey site, which were potential confounders of the association between physical activity and other coronary heart disease risk factors. After adjustment, significant associations remained between levels of exercise participation and HDL cholesterol level, HDL/total cholesterol ratio and serum triglyceride levels for both sexes. In women, there was also a significant relationship between activity level and body mass index. In addition, for men only, there was a significant inverse relationship between physical activity and total cholesterol, and, for older men, between physical activity and systolic blood pressure. It is well recognised that physical activity has an independent effect on reducing the risk of coronary heart disease. The results of this study suggest that there may be small supplementary effects mediated through the relationship between exercise and other biological cardiovascular risk factors.

Acute changes in lipid, lipoprotein, apolipoprotein, and low-density lipoprotein particle size after an endurance triathlon

The effect of an endurance triathlon (2.4-mile swim, 112-mile bicycle ride, 26.2-mile run, in succession) on plasma total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, apolipoprotein (apo) A-I and B levels, and LDL particle size was determined in 34 male and six female participants 6 to 12 hours before and immediately after the completion of the triathlon. Plasma TG decreased significantly (70% decrease) in both men and women. In men the change in plasma TG was inversely associated with baseline TG values (P less than .0001). Plasma TC and LDL cholesterol did not change significantly in male athletes but decreased significantly in women. A significant increase in HDL cholesterol was observed in both men (18% increase, P less than .0001) and women (5% increase, P less than .01). In men the increase in HDL cholesterol was inversely correlated with the decrease in triglycerides (P less than .0002). Plasma apo A-I levels increased significantly only in the male group (P less than .005), whereas plasma apo B levels decreased significantly in both men and women (P less than .0005). LDL particle size increased in seven males, whereas in the remaining males and all females no change in LDL size was observed. The increase in LDL particle size in these seven subjects was associated with a greater decline in plasma TG compared with the remaining men (P less than .005) and women (P less than .03). These results indicate that prolonged strenuous physical exercise can induce acute modifications of plasma lipoproteins, which may in part be related to enhanced lipolysis.

Clinical Applications for Exercise

In brief: The body adapts to regular exercise by making central and peripheral physiologic adjustments. Although exercise doesn't reverse pathologic changes, it may play a significant role in the management of certain diseases. Thus physicians can prescribe exercise as therapy. For example, exercise increases calorie consumption but conserves lean body mass, which is an important consideration in the management of obesity. Exercise also has been shown to lower blood pressure-a desirable outcome for patients with hypertension. Similarly, diabetic patients may benefit from regular exercise because it improves glucose tolerance. The author discusses these and other interactions between physiology and exercise and their application to treatment of specific diseases.

Increasing exercise among blue-collar employees: the tailoring of worksite programs to meet specific needs

Despite increasing interest in worksite exercise programs, little attention has been focused on the blue-collar segment of the workforce. Because of their low participation in traditional exercise classes and programs, blue-collar workers at a university were targeted for an exercise program tailored specifically to their preferences and needs. Thirty-eight sedentary males employed in operations and maintenance shops on the university campus were evaluated with regard to their current exercise behavior, other health habits, and their preferred types of physical activity programs. A pre- and postprogram submaximal exercise test, weight, and blood pressure measurements were also completed on-site. Twenty-two men (23% of the total blue-collar population) subsequently participated in a 16-week exercise program using an on-site parcourse, and incorporating such motivational strategies as public monitoring, intershop competition, and activity-based incentives. Participation rates were substantially higher than those recorded for previous worksite exercise classes. Participants showed increases in fitness levels (P less than 0.0001) and decreases in weight (P less than 0.05) compared with nonparticipants. Suggestions concerning recruitment of such individuals into low-cost exercise programs and subsequent participation maintenance are discussed.

Effects of exercise on plasma fibrinolytic activity in patients with ischaemic heart disease

In order to investigate the response of plasma fibrinolytic activity to exercise in patients with ischaemic heart disease, we studied 109 patients with chronic stable angina pectoris. All patients were exercised on the treadmill according to the Bruce protocol. They were subsequently divided into 2 groups according to the results of exercise testing. The first group comprised 47 patients with negative exercise tests and the second group 62 patients with positive exercise tests. The plasma fibrinolytic activity was determined in all patients by the method of euglobulin lysis time before exercise, at peak exercise and 2 hours later. The results were compared with those of a control group which consisted of 30 normal healthy volunteers. In the control group there was a significant increase of plasma fibrinolytic activity (P less than 0.001) at peak exercise, which almost returned to the resting levels at 2 hours. In all patients with angina, resting and peak exercise fibrinolytic activity level was significantly lower than that of the control group (P less than 0.01 and less than 0.001, respectively), although at peak exercise it also increased significantly (P less than 0.001) compared to resting levels and it remained elevated at 2 hours after exercise (P less than 0.001). In patients with negative exercise test, plasma fibrinolytic activity at rest was almost identical to that of the control group, it increased with exercise (P less than 0.001) but to values below those of the control group (P less than 0.01) and although there was a tendency to return to resting levels it remained elevated (P less than 0.01) at 2 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Strategies for increasing early adherence to and long-term maintenance of home-based exercise training in healthy middle-aged men and women

Two studies were undertaken to compare strategies for the adoption and maintenance of moderate-intensity, home-based exercise training. In the study of adoption, 52 men and women who had served for 6 months as controls for a study of moderate-intensity, home-based exercise training received 30 minutes of baseline instruction. They were then randomized to receive continuing instruction and support through 10 staff-initiated telephone contacts of 5 minutes each every 2 weeks, or to receive no telephone contacts. In subjects receiving telephone contacts, peak oxygen uptake increased significantly after 6 months, whereas no increase was observed in subjects receiving no staff support (p less than 0.05). In the maintenance study, 51 men and women who had significantly increased their peak oxygen uptake by 6 months of moderate-intensity, home-based exercise training were randomized to undergo daily self-monitoring and receive adherence instructions, or undergo weekly self-monitoring only, during a second 6-month period of training. Subjects performing daily self-monitoring reported completing significantly more exercise training sessions during the 6 months of training than subjects performing weekly self-monitoring; functional capacity in both groups remained higher than before training (p less than 0.05). Taken together, these studies suggest that brief baseline instruction followed by continuing telephone contact with staff can be used to help people adopt a moderate-intensity, home-based exercise training program that can be maintained by simple self-monitoring strategies.

Response of some haemocoagulatory and haemorheological variables to maximal exercise in sedentary and active subjects

The purpose of this study was to evaluate how physical conditioning is associated with haemostatic and rheological responses to strenuous exercise. A total of 25 males, divided into two groups differing in exercise fitness (14 sedentary and 11 active), underwent exercise testing on a bicycle ergometer with an initial 25 W workload increasing by the same amount every 3 min. The following variables were evaluated before and after the test: platelet count and aggregability, plasma fibrinogen, fibrinolytic degradation products, viscometry and micro-haematocrit. Significant differences in baseline values between the two groups were found only for blood viscosity. Irrespective of the group, significantly increased values were demonstrated for all the variables, except platelet aggregability and fibrinogen levels, in response to strenuous exercise. It is concluded that the possible protective effect of exercise against cardiovascular disease does not seem to be related to changes in the haemorheological and haemostatic measures evaluated.

Exercise in cardiovascular disease

Exercise has assumed an important role in the treatment of cardiovascular disease (CVD) and, as one of the potentially modifiable risk factors, is also an important component of primary prevention efforts. This article briefly reviews exercise applications in coronary heart disease, hypertension, Type A behavior pattern, diabetes, hyperlipidemia, and obesity. Although increased physical activity offers many potential physical and psychological benefits in CVD patients, all too often the benefits are not realized because of poor adherence to prescribed exercise regimens. Behavioral research indicates that manipulating the antecedents and consequences of physical activity can improve short-term exercise adherence; several studies also suggest that characteristics such as the intensity of the exercise may influence adherence. Exercise in CVD is a challenging area for future research in behavioral medicine.