Assessment by a microprocessor of adherence to home-based moderate-intensity exercise training in healthy, sedentary middle-aged men and women

Accelerometer feedback to promote physical activity in adults with type 2 diabetes: a pilot study

This study examined whether giving activity feedback to obese, sedentary adults with Type 2 diabetes would improve their adherence to a home-based walking program. 49 subjects were recruited. Ten failed a treadmill cardiovascular test. Another 9 dropped out before the intervention, and 4 dropped out during the intervention. The remaining 26 adults (14 women, 12 men; age M = 48.1 yr., SD = 7.1) received behavioral counseling monthly for 3 mo. regarding exercise. All subjects wore a triaxial accelerometer during these 3 months. Randomly, half of the subjects were blind to the data from the accelerometers, i.e., no feedback, and had counseling based on their self-report diaries. The other half had access to the accelerometer data, got a computerized graph of their physical activity for the period between counseling sessions, and had counseling based on these objective data, i.e., feedback. The feedback group showed an increase in exercise over the 3 mo. The nonfeedback group showed an increase in activity at 1.5 mo. but reverted to their baseline exercise levels at 3 mo. However, analysis of variance showed there was at least an 8% probability that this effect was due to chance, so the hypothesis that feedback would improve exercise adherence could not be supported. Further studies with larger sample sizes and greater control of experimental conditions are needed to determine the utility of objective activity feedback.

A practical guide to exercise training for heart failure patients

BACKGROUND

Exercise training has been shown to improve exercise capacity in patients with heart failure. We sought to examine the optimal strategy of exercise training for patients with heart failure.

METHODS

Review of the published data on the characteristics of the training program, with comparison of physiologic markers of exercise capacity in heart failure patients and healthy individuals and comparison of the change in these characteristics after an exercise training program.

RESULTS

Many factors, including the duration, supervision, and venue of exercise training; the volume of working muscle; the delivery mode (eg, continuous vs. intermittent exercise), training intensity; and the concurrent effects of medical treatments may influence the results of exercise training in heart failure. Starting in an individually prescribed and safely monitored hospital-based program, followed by progression to an ongoing and progressive home program of exercise appears to be the best solution to the barriers of anxiety, adherence, and "ease of access" encountered by the heart failure patient.

CONCLUSIONS

Various exercise training programs have been shown to improve exercise capacity and symptom status in heart failure, but these improvements may only be preserved with an ongoing maintenance program.

Effects of an off-site walking program on energy expenditure, serum lipids, and glucose metabolism in middle-aged women

The present study aims to identify the effects of systematic walking on exercise energy expenditure (EEE) and blood profiles in middle-aged women. Fifty-two female nurse managers, aged 32 to 57 years (42.0 +/- 6.2), were randomly assigned to an intervention group (IG) and a control group (CG) for a 12-week study of the walking program. EEE was measured using a microelectronic device. Blood profiles were assessed before and after the walking program. The mean EEE (kcal/kg/d) in the IG and CG was 4.73 +/- 1.02 and 3.88 +/- 0.81 (P = 0.01), indicating an increase of 1.17 +/- 0.98 and 0.46 +/- 0.68 from baseline (P = 0.01), respectively. The mean change in high-density lipoprotein cholesterol in the IG and CG was 1.8 +/- 8.3 mg/dL and -2.9 +/- 7.0 mg/dL (P = 0.051); that in insulin was -4.5 +/- 7.5 microU/dL and -0.6 +/- 4.3 microU/dL (P = 0.046), respectively. These results show that systematic walking increases EEE and improves blood profiles.

Effects of moderate-intensity exercise on physiological, behavioral, and emotional responses to family caregiving: a randomized controlled trial

BACKGROUND

The study objective was to determine the health and quality-of-life effects of moderate-intensity exercise among older women family caregivers.

METHODS

This 12-month randomized controlled trial involved a volunteer sample of 100 women aged 49 to 82 years who were sedentary, free of cardiovascular disease, and caring for a relative with dementia. Participants were randomized to 12 months of home-based, telephone-supervised, moderate-intensity exercise training or to an attention-control (nutrition education) program. Exercise consisted of four 30- to 40-minute endurance exercise sessions (brisk walking) prescribed per week at 60% to 75% of heart rate reserve based on peak treadmill exercise heart rate. Main outcomes were stress-induced cardiovascular reactivity levels, rated sleep quality, and reported psychological distress.

RESULTS

Compared with nutrition participants (NU), exercise participants (EX) showed significant improvements in the following: total energy expenditure (baseline and post-test means [SD] for EX = 1.4 [1.9] and 2.2 [2.2] kcal/kg/day; for NU = 1.2 [1.7] and 1.2 [1.6] kcal/kg/day; p <.02); stress-induced blood pressure reactivity (baseline and post-test systolic blood pressure reactivity values for EX = 21.6 [12.3] and 12.4 [11.2] mm Hg; for NU = 17.9 [10.2] and 17.7 [13.8] mm Hg; p <.024); and sleep quality (p <.05). NU showed significant improvements in percentages of total calories from fats and saturated fats relative to EX (p values <.01). Both groups reported improvements in psychological distress. Conclusions. Family caregivers can benefit from initiating a regular moderate-intensity exercise program in terms of reductions in stress-induced cardiovascular reactivity and improvements in rated sleep quality.

Methodologic issues in measuring physical activity and physical fitness when evaluating the role of dietary supplements for physically active people

Physical activity and physical fitness are complex entities comprising numerous diverse components that present a challenge in terms of accurate, reliable measurement. Physical activity can be classified by its mechanical (static or dynamic) or metabolic (aerobic or anaerobic) characteristics and its intensity (absolute or relative to the person's capacity). Habitual physical activity can be assessed by using a variety of questionnaires, diaries, or logs and by monitoring body movement or physiologic responses. Selection of a measurement method depends on the purpose of the evaluation, the nature of the study population, and the resources available. The various components of physical fitness can be assessed accurately in the laboratory and, in many cases, in the field by using a composite of performance tests. Most coaches and high-level athletes would accept as very beneficial a dietary supplement that would increase performance in a competitive event by even 3%; for example, lowering a runner's time of 3 min, 43 s in the 1500 m by 6.7 s. To establish that such small changes are caused by the dietary supplement requires carefully conducted research that involves randomized, placebo-controlled, double-blind studies designed to maximize statistical power. Statistical power can be increased by enlarging sample size, selecting tests with high reliability, selecting a potent but safe supplement, and maximizing adherence. Failure to design studies with adequate statistical power will produce results that are unreliable and will increase the likelihood that a true effect will be missed.

Compliance with cardiovascular disease prevention strategies: a review of the research

The efficacy of cardiovascular risk-reduction programs has been established. However, the extent to which risk-reduction interventions are effective may depend on adherence. Non-compliance, or non-adherence, may occur with any of the recommended or prescribed regimens and may vary across the treatment course. Compliance problems, whether occurring early or late in the treatment course, are clinically significant, as adherence is one mediator of the clinical outcome. This article, which is based on a review of the empirical literature of the past 20 years, addresses compliance across four regimens of cardiovascular risk reduction: pharmacological therapy, exercise, nutrition, and smoking cessation. The criteria for inclusion of a study in this review were: (a) focus on cardiovascular disease risk reduction; (b) report of a quantitative measure of compliance behavior; and (c) use of a randomized controlled design. Forty-six studies meeting these criteria were identified. A variety of self-report, objective, and electronic measurement methods were used across these studies. The interventions employed diverse combinations of cognitive, educational, and behavioral strategies to improve compliance in an array of settings. The strategies demonstrated to be successful in improving compliance included behavioral skill training, self-monitoring, telephone/mail contact, self-efficacy enhancement, and external cognitive aids. A series of tables summarize the intervention strategies, compliance measures, and findings, as well as the interventions demonstrated to be successful. This review reflects the progress made over two decades in compliance measurement and research and, further, advances made in the application of behavioral strategies to the promotion of cardiovascular risk reduction.

Brisk walking and serum lipid and lipoprotein variables in previously sedentary women--effect of 12 weeks of regular brisk walking followed by 12 weeks of detraining

The purpose of this study was to examine the effectiveness of brisk walking as a means of improving endurance fitness and influencing serum lipid and lipoprotein variables in previously sedentary women. Walkers (n = 10, mean (s.e.m.) age 47.3(2.0) years) followed a programme of brisk walking (mean(s.e.m.) speed 1.76(0.03) m s-1) for 12 weeks, after which the training stimulus was withdrawn. Controls (n = 10, mean(s.e.m.) age 41.6(1.2) years) maintained their habitual sedentary lifestyle throughout. Endurance fitness was determined using laboratory measures of responses to treadmill walking. Serum lipid and lipoprotein variables were determined in venous blood (12-h fasted). Body fatness was assessed by anthropometry and dietary practice using the 7-day weighed food intake technique. Measurements were repeated after 12 and 24 weeks. Brisk walking resulted in a decrease in heart rate and blood lactate concentration during exercise, while detraining was accompanied by a reversal of these changes. Changes in body mass and the ratio of circumferences at the waist and hip did not differ between groups but the sum of four skinfolds decreased with brisk walking and increased with detraining. High density lipoprotein (HDL) and HDL2 cholesterol increased with walking and decreased with detraining but no between group changes (analysis of variance, P < 0.05) were found in other lipid and lipoprotein variables. These findings suggest that regular brisk walking can improve endurance fitness and increase HDL cholesterol concentration in sedentary women.

Issues in contemporary cardiac rehabilitation: a historical perspective

Cardiac rehabilitation consists of exercise, psychosocial support and education and is prescribed most often for patients with coronary heart disease. Its purpose is to facilitate readaptation to normal life through the achievement of maximal functional capability and to reduce heart disease risk factors. It began historically with progressive ambulation after myocardial infarction and by 1980 became a standardized inpatient therapy performed according to a stepped procedure. Predischarge exercise testing was added and has become a meaningful contribution to the concept of risk stratification after an acute coronary event. Rehabilitation has subsequently become part of the outpatient environment and is delivered by multiple models. Meta-analyses have shown that rehabilitation reduces overall and cardiovascular deaths by about 20% and sudden death by about 37% during the year after an acute myocardial infarction. The significance of this, however, must now be modulated by the dynamic role of aggressive coronary intervention. Selection for such intervention has become an important adjunctive aspect of rehabilitation. Newer findings suggest that those stratified at low risk will benefit most by the modification of coronary risk factors, and that patients previously thought to be poor candidates for rehabilitation (such as those with significant left ventricular dysfunction and low work capacity) may experience substantial relative functional benefit. Beyond risk stratification, important contemporary issues include surveillance of patients after angioplasty, the effectiveness of rehabilitation in the attenuation or reversal of both native and vein graft atherosclerosis and consideration of such currently emphasized end points as quality of life and economic evaluation.

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.

Training effects of long versus short bouts of exercise in healthy subjects

To evaluate the "threshold" duration of exercise required to produce training effects, 18 healthy men aged 51 +/- 6 years completing 30 minutes of exercise training/day were compared with 18 men aged 52 +/- 6 years completing three 10-minute bouts of exercise/day, each separated by at least 4 hours. Exercise training intensity was moderate (65 to 75% of peak treadmill heart rate). During the 8-week study period VO2 max increased significantly in both groups from 33.3 +/- 3.2 to 37.9 +/- 3.5 ml/kg/min in men performing long exercise bouts and from 32.1 +/- 4.6 to 34.5 +/- 4.5 ml/kg/min in men performing short exercise bouts (p less than 0.05 within and between groups). Adherence to unsupervised exercise training performed at home and at work by men in long and short bouts was high; total duration of training completed was 96 and 93% of the prescribed amount and total number of sessions completed was 92 and 93% of that prescribed, respectively. In both groups exercise heart rate measured by a portable microprocessor was within or above the prescribed range for greater than 85% of the prescribed duration. Thus, multiple short bouts of moderate-intensity exercise training significantly increase peak oxygen uptake. For many individuals short bouts of exercise training may fit better into a busy schedule than a single long bout.