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Biomedical subjects

A L Dunn

Publications and source records attributed to A L Dunn.

At least 19 recordsLinked to original sources

Using Rasch modeling to re-evaluate three scales related to physical activity: enjoyment, perceived benefits and perceived barriers.

Studies suggest that enjoyment, perceived benefits and perceived barriers may be important mediators of physical activity. However, the psychometric properties of these scales have not been assessed using Rasch modeling. The purpose of this study was to use Rasch modeling to evaluate the properties of three scales commonly used in physical activity studies: the Physical Activity Enjoyment Scale, the Benefits of Physical Activity Scale and the Barriers to Physical Activity Scale. The scales were administered to 378 healthy adults, aged 25-75 years (50% women, 62% Whites), at the baseline assessment for a lifestyle physical activity intervention trial. The ConQuest software was used to assess model fit, item difficulty, item functioning and standard error of measurement. For all scales, the partial credit model fit the data. Item content of one scale did not adequately cover all respondents. Response options of each scale were not targeting respondents appropriately, and standard error of measurement varied across the total score continuum of each scale. These findings indicate that each scale's effectiveness at detecting differences among individuals may be limited unless changes in scale content and response format are made.

Evaluation Studies as Topic↗

Does adherence to a lifestyle physical activity intervention predict changes in physical activity?

This study examined whether adherence to a lifestyle physical activity intervention predicted weekly participation in at least 150 min of moderate to vigorous physical activity among 244 sedentary healthy adults. Structural equation modeling was used to assess the association between adherence and physical activity. Markers of adherence were attendance, homework completion, and self-monitoring for a group-based intervention and telephone call completion, homework completion, and self-monitoring for a telephone and mail-delivered intervention. For both interventions, adherence significantly predicted moderate to vigorous physical activity. Adherence to lifestyle physical activity interventions ought to be encouraged to increase the likelihood that participants will engage in an adequate amount of physical activity for health benefits to occur.

Adult↗

Physical activity dose-response effects on outcomes of depression and anxiety.

PURPOSE: The purpose of this study was to examine the scientific evidence for a dose-response relation of physical activity with depressive and anxiety disorders. METHODS: Computer database searches of MEDLINE, PsychLit, and Internet and personal retrieval systems to locate population studies, randomized controlled trials (RCTs), observational studies, and consensus panel judgments were conducted. RESULTS: Observational studies demonstrate that greater amounts of occupational and leisure time physical activity are generally associated with reduced symptoms of depression. Quasi-experimental studies show that light-, moderate-, and vigorous-intensity exercise can reduce symptoms of depression. However, no RCTs have varied frequency or duration of exercise and controlled for total energy expenditure in studies of depression or anxiety. Quasi-experimental and RCTs demonstrate that both resistance training and aerobic exercise can reduce symptoms of depression. Finally, the relation of exercise dose to changes in cardiorespiratory fitness is equivocal with some studies showing that fitness is associated with reduction of symptoms and others that have demonstrated reduction in symptoms without increases in fitness. CONCLUSION: All evidence for dose-response effects of physical activity and exercise come from B and C levels of evidence. There is little evidence for dose-response effects, though this is largely because of a lack of studies rather than a lack of evidence. A dose-response relation does, however, remain plausible.

Adult↗

Evaluating the reproducibility and validity of the Aerobic Adaptation Test.

PURPOSE: To examine the reproducibility and validity of a new submaximal, ramped cycle ergometer testing methodology known as the Aerobic Adaptation Test (AAT), which attempts to detect changes in submaximal work capacity and minimize participant discomfort. METHODS: 36 sedentary men (mean age = 48.1 +/- 10.2 yr [SD]) and 22 sedentary women (mean age = 51.9 +/- 10.2 yr [SD]) participated in the study. To test reproducibility, participants were tested twice with an average of 20 d between tests (+/-15 d). To test validity, participants were tested before and after a 6-month physical activity intervention, and outcomes were compared with standard measures of fitness (exercise time and oxygen consumption at 70% max heart rate). The main outcome variable of the AAT was work output (W) over a period of 3 min after reaching 70% maximal heart rate. RESULTS: The average work output at 70% HRmax was highly reproducible, with a test-retest reliability of rho = 0.85 (P < 0.001). Average work output at 70% HRmax significantly increased after 6 months of physical activity intervention (87.8 +/- 32.9 W vs 95.5 +/- 37.9 W, P = 0.002), and changes in average work output at 70% HRmax correlated with changes in exercise time to elicit 70% HRmax (r = 0.87, P < 0.001) as well as changes in VO2 at 70% HRmax (r = 0.75, P < 0.001). Thus, the AAT appears to be a valid measure of submaximal work capacity. CONCLUSIONS: The AAT is a reproducible and valid measure of submaximal work capacity that can serve as an effective means to evaluate physical activity interventions.

Adaptation, Physiological↗

Characteristics of inactive primary care patients: baseline data from the activity counseling trial. For the Activity Counseling Trial Research Group.

BACKGROUND: Although many primary care patients are inactive, being able to classify even small amounts and intensities of activity and factors associated with these activity levels could be helpful for physicians who are trying to motivate their patients to become more physically active. METHODS: Sociodemographics, physical activity, fitness, other cardiovascular risk factors, and psychosocial measures were measured at baseline in the 874 patients in the Activity Counseling Trial. Patients were categorized into three groups: (1) no moderate-to-vigorous physical activity (MVPA), (2) some moderate but no vigorous activity, and (3) some vigorous activity. Multiple logistic regression was used to determine factors cross-sectionally associated with activity intensity. RESULTS: One or more cardiovascular risk factors in addition to physical inactivity were present in 84% of participants. Maximal oxygen uptake averaged 25.2 ml/kg/min; 85% had poor to fair aerobic fitness. Physical activity averaged 32.7 kcal/kg/day, with 13.5 min of MVPA/day; 26% engaged in some vigorous activity, 11% engaged in no MVPA. In unadjusted analyses, gender, age, race, education, income, employment, smoking, alcohol use, and exercise self-efficacy were associated with activity intensity (P = 0.05-0.001). A greater percentage engaged in moderate than in vigorous activity in all subgroups. In multiple logistic regression analyses, odds ratios (95% confidence intervals) for engaging in vigorous activity were 0. 39 (0.28, 0.56) for women, 0.38 (0.19, 0.75) for 65+ compared with 35- to 44-year-olds, and 1.14 (1.06, 1.22) for 10-unit increases in performance self-efficacy score. CONCLUSIONS: Most primary care patients who are physically inactive have additional cardiovascular risk factors, particularly overweight and obesity. All subgroups pursue moderate-intensity activity more often than vigorous activity. Women, older persons, and those with lower exercise self-efficacy are less likely to engage in vigorous activity.

Adult↗

Exercise management of obesity.

When dealing with overweight patients, it is important to treat obesity as a chronic condition requiring long-term management. Physicians do not send a patient with hypertension home with just one bottle of pills and expect blood pressure to be managed forever. Similarly, it is naive to think that sending an overweight patient home with only a single word of advice to "lose weight" will solve the problem. Medical staff would be wise to adopt the attitude that obesity requires long-term intervention and management, just as hypertension requires ongoing monitoring and management. Continued attention to patients' physical activity is required. It is important for physicians to spend a few minutes discussing physical activity with their patients. The patient's current and past levels of physical activity should be assessed as well as the barriers to and benefits of activity. Normal-weight patients should accumulate at least 30 minutes of moderate-intensity activity on most days of the week, and overweight patients should accumulate 60 to 80 minutes per day, every day. The physician can provide some simple tools, such as a step counter and self-monitoring forms, to promote increases in activity and can follow up with the patient after the office visit. This information may sound like a lot to cover, especially given the limited time available for each patient. By spending 3 to 5 minutes intervening, however, physicians can play a critical role in promoting health. Physicians should set a goal to address one specific topic (e.g., a brief discussion of exercise benefits and barriers) and try one strategy (e.g., introduce self-monitoring) during the next counseling session with patients. It is also important for physicians to remember that their success in changing behavior may be in small increments. These small changes can and do eventually lead to success for many patients and physicians.

Adult↗

Heart rate variability, trait anxiety, and perceived stress among physically fit men and women.

BACKGROUND: It is unclear from prior reports whether the relationships between self-ratings of anxiety or emotional stress and parasympathetic nervous system components of heart rate variability are independent of personality and cardiorespiratory fitness. We examined those relationships in a clinical setting prior to a standardized exercise test. METHODS AND RESULTS: Heart rate variability (HRV) was measured during 5 min of supine rest among 92 healthy men (N=52) and women (N=40) who had above-average cardiorespiratory fitness as indicated by peak oxygen uptake measured during grade-incremented treadmill exercise. HRV datasets were decomposed into low-frequency (LF; 0.05-0.15 Hz) and high-frequency (HF; 0.15-0.5 Hz) components using spectral analysis. Self-ratings of trait anxiety and perceived emotional stress during the past week were also assessed. CONCLUSIONS: There was an inverse relationship between perceived emotional stress during the past week and the normalized HF component of HRV (P=0.038). This indicates a lower cardiac vagal component of HRV among men and women who perceived more stress. That relationship was independent of age, gender, trait anxiety, and cardiorespiratory fitness. It was also independent of heart rate; mean arterial blood pressure; and respiration rate, factors which can influence HRV and might be elevated among people reporting anxiety and perceived stress. We conclude that vagal modulation of heart period appears to be sensitive to the recent experience of persistent emotional stress, regardless of a person's level of physical fitness and disposition toward experiencing anxiety.

Adult↗

Cost-effectiveness of lifestyle and structured exercise interventions in sedentary adults: results of project ACTIVE.

BACKGROUND: Project ACTIVE was a randomized clinical trial comparing two physical activity interventions, lifestyle and traditional structured exercise. The two interventions were evaluated and compared in terms of cost effectiveness and ability to enhance physical activity among sedentary adults. DESIGN: This was a randomized clinical trial. SETTING/ PARTICIPANTS: The study included 235 sedentary but healthy community-dwelling adults. INTERVENTION: A center-based lifestyle intervention that consisted of behavioral skills training was compared to a structured exercise intervention that included supervised, center-based exercise. MAIN OUTCOME MEASURES: The main outcome measures of interest included cost, cardiorespiratory fitness, and physical activity. RESULTS: Both interventions were effective in increasing physical activity and fitness. At 6 months, the costs of the lifestyle and structured interventions were, respectively, $46.53 and $190.24 per participant per month. At 24 months these costs were $17.15 and $49.31 per participant per month. At both 6 months and 24 months, the lifestyle intervention was more cost-effective than the structured intervention for most outcomes measures. CONCLUSIONS: A behaviorally-based lifestyle intervention approach in which participants are taught behavioral skills to increase their physical activity by integrating moderate-intensity physical activity into their daily lives is more cost-effective than a structured exercise program in improving physical activity and cardiorespiratory health. This study represents one of the first attempts to compare the efficiency of intervention alternatives for improving physical activity among healthy, sedentary adults.

Adult↗

Physical activity behavior change: issues in adoption and maintenance.

The many benefits of participation in regular moderate- or vigorous-intensity physical activity are well established, yet more than 60% of the population is sedentary or insufficiently active. Published studies have revealed that behavior modification and cognitive-behavior modification can be successfully used to assist patients, healthy adults, and youth in the adoption of physically active lifestyles. However, few studies with adults and youth have examined the maintenance of physical activity behavior beyond 6 months of adoption of this behavior. Maintenance of physical activity is critically important because ongoing participation in the behavior is necessary to sustain health benefits. Knowledge of effective intervention strategies for long-term maintenance of physical activity is at an early stage. The authors provide a summary of what is known about the maintenance of physical activity behavior in adults and youth and how physical activity behavior relates to other health behaviors such as smoking, as well as recommendations for research on physical activity behavior change and maintenance.

Adolescent↗

Adverse events during use of intranasal desmopressin acetate for haemophilia A and von Willebrand disease: a case report and review of 40 patients.

We report our experience with the incidence of adverse events during the use of Stimate brand intranasal desmopressin acetate (IN DDAVP) for patients with haemophilia A (HA) or von Willebrand disease (vWD) after noting two severe adverse events in one adult patient. All patients with documented vWD (type 1 or 2 A) or haemophilia A (mild, moderate or symptomatic carrier) from the Emory Comprehensive Hemophilia Center who had IN DDAVP challenge testing or were using Stimate for treatment of bleeding were evaluated for adverse events by patient report or nursing observation of clinical signs and symptoms. Forty patients were studied. Sixty-eight per cent (27/40) experienced clinical signs and/or symptoms. The majority of these symptoms were mild, however several patients reported moderate to severe side-effects and one adult patient required medical intervention for symptomatic hyponatraemia. In our experience, two-thirds of patients tested experienced adverse signs and/or symptoms with the use of Stimate; considerably higher than that reported from preliminary results in the literature. Young age did not correlate positively with adverse reactions. Severe adverse events requiring medical intervention were rare, however symptoms such as moderate to severe headache, nausea, vomiting and weakness may necessitate evaluation for hyponatraemia. This is the first report of symptomatic hyponatraemia in an adult patient with recommended dosing of Stimate. Side-effects may be minimized if patients adhere to instructions regarding fluid intake and composition while using IN DDAVP.

Administration, Intranasal↗

Variables related to meeting the CDC/ACSM physical activity guidelines.

PURPOSE: The purpose of this study was to investigate the relation between perceived importance of physical activity and demographic variables and current physical activity level with specific reference to the CDC/ACSM guidelines for sufficient physical activity for a health benefit. METHODS: Physical activity levels were assessed by a telephone survey of 2002 households throughout the continental United States and the District of Columbia to determine whether the individuals met the CDC/ACSM physical activity guidelines. RESULTS: Results indicate that 68% of the respondents are physically active below the CDC/ACSM criterion. Chi-square analysis revealed significant relationships between meeting the CDC/ACSM physical activity guidelines and 1) perceived importance of physical inactivity as a health risk (P < 0.0001), and 2) gender (P < 0.0001). Logistic regression analysis revealed that having a greater awareness of the health risks of physical inactivity improved the odds ratio (OR = 1.40, 95% CI = 1.21-1.62) of being sufficiently physically active for a health benefit by 40% (P < 0.0001) and being a male improved the odds ratio (OR = 1.45, 95% CI = 1.17-1.79) of being sufficiently physically active for a health benefit by 45% (P < 0.0006). CONCLUSIONS: Implications for health and physical fitness researchers and practitioners are that they need to improve awareness of life span fitness benefits and develop intervention programs based on individuals' current physical activity levels.

Aged↗

Comparison of lifestyle and structured interventions to increase physical activity and cardiorespiratory fitness: a randomized trial.

CONTEXT: Even though the strong association between physical inactivity and ill health is well documented, 60% of the population is inadequately active or completely inactive. Traditional methods of prescribing exercise have not proven effective for increasing and maintaining a program of regular physical activity. OBJECTIVE: To compare the 24-month intervention effects of a lifestyle physical activity program with traditional structured exercise on improving physical activity, cardiorespiratory fitness, and cardiovascular disease risk factors. DESIGN: Randomized clinical trial conducted from August 1, 1993, through July 31, 1997. PARTICIPANTS: Sedentary men (n = 116) and women (n = 119) with self-reported physical activity of less than 36 and 34 kcal/kg per day, respectively. INTERVENTIONS: Six months of intensive and 18 months of maintenance intervention on either a lifestyle physical activity or a traditional structured exercise program. MAIN OUTCOME MEASURES: Primary outcomes were physical activity assessed by the 7-Day Physical Activity Recall and peak oxygen consumption (VO2peak) by a maximal exercise treadmill test. Secondary outcomes were plasma lipid and lipoprotein cholesterol concentrations, blood pressure, and body composition. All measures were obtained at baseline and at 6 and 24 months. RESULTS: Both the lifestyle and structured activity groups had significant and comparable improvements in physical activity and cardiorespiratory fitness from baseline to 24 months. Adjusted mean changes (95% confidence intervals [CIs]) were 0.84 (95% CI, 0.42-1.25 kcal/kg per day; P<.001) and 0.69 (95% CI, 0.25-1.12 kcal/kg day; P = .002) for activity, and 0.77 (95% CI, 0.18-1.36 mL/kg per minute; P = .01) and 1.34 (95% CI, 0.72-1.96 mL/kg per minute; P<.001) for VO2peak for the lifestyle and structured activity groups, respectively. There were significant and comparable reductions in systolic blood pressure (-3.63 [95% CI, -5.54 to -1.72 mm Hg; P<.001] and -3.26 [95% CI, -5.26 to -1.25 mm Hg; P = .002]) and diastolic blood pressure (-5.38 [95% CI, -6.90 to -3.86 mm Hg; P<.001] and -5.14 [95% CI, -6.73 to -3.54 mm Hg; P<.001) for the lifestyle and structured activity groups, respectively. Neither group significantly changed their weight (-0.05 [95% CI, -1.05 to 0.96 kg; P = .93] and 0.69 [95% CI, -0.37 to 1.74 kg; P = .20]), but each group significantly reduced their percentage of body fat (-2.39% [95% CI, -2.92% to -1.85%; P<.001] and -1.85% [95% CI, -2.41 % to -1.28%; P<.001]) in the lifestyle and structured activity groups, respectively. CONCLUSIONS: In previously sedentary healthy adults, a lifestyle physical activity intervention is as effective as a structured exercise program in improving physical activity, cardiorespiratory fitness, and blood pressure.

Adult↗

Lifestyle physical activity interventions. History, short- and long-term effects, and recommendations.

INTRODUCTION: Lifestyle physical activity interventions have resulted in response to the public health problem of promoting regular amounts of physical activity to the majority of U.S. adults who remain inadequately or completely inactive. These lifestyle interventions allow a person to individualize his/her physical activity programs to include a wide variety of activities that are at least of moderate intensity and to accumulate bouts of these activities in a manner befitting his/her life circumstances. METHODS: We reviewed the history of lifestyle physical activity interventions and defined lifestyle physical activity based on this review. We located 14 studies that met this definition. RESULTS: Lifestyle physical activity interventions are effective at increasing and maintaining levels of physical activity that meet or exceed public health guidelines for physical activity in representative samples of previously sedentary adults and obese children. The majority of these interventions have been delivered by face-to-face contact in small groups, which limits their public health impact. However, a small number of studies demonstrate that these interventions can be delivered by mail and telephone, which may enhance their generalizability. Most of these studies utilized behavior change theories such as Social Cognitive Theory, the Transtheoretical Model, and Behavior Learning to shape the interventions. Lifestyle interventions aimed at modifying the environment, such as signs posted to increase stair climbing, also have been shown to be effective over the short term. CONCLUSIONS: The major issues concerning lifestyle physical activity interventions are: (1) testing their ability to be implemented on a large scale; (2) examining cost-effectiveness for different modes of delivery; and (3) researching the efficacy in populations such as the elderly, minorities, economically disadvantaged, and individuals with concurrent disease. More studies aimed at manipulating the environment to increase physical activity need to be tested over periods of one year or longer. It is possible that lifestyle interventions could be integrated and delivered by new technologies such as interactive computer-mediated programs, telephone, or computer web-based formats. All of these recommended approaches should utilize valid and reliable measures of physical activity and should examine the health effects, particularly on a longitudinal basis. Basic dose-response studies in controlled settings also are needed to help us understand the health effects of accumulated moderate intensity activity.

Adult↗

A randomized trial of physical activity interventions: design and baseline data from project active.

We report here the design and baseline data from Project Active, a 2-yr randomized trial designed to compare the effectiveness of a Lifestyle physical activity intervention with the traditional Structured exercise prescription approach. Primary outcome measures are energy expenditure in physical activity (estimated by kcal per kilogram of body weight of energy expenditure) and cardiorespiratory fitness (measured by maximal oxygen uptake). The participants, 235 initially sedentary and apparently healthy adults, were randomized into either the Lifestyle or Structured intervention groups. The Lifestyle treatment consists of a personalized approach that accounts for an individual's motivational readiness and preferences for integrating physical activity into daily routines. The Structured approach is the familiar exercise prescription that is based on a frequency, intensity, and duration formula. The primary hypothesis to be tested is that there will be a difference in physical activity and cardiorespiratory fitness measures between the two conditions at the end of 24 months. The secondary hypothesis is that both groups will make significant improvements from baseline in physical activity and cardiorespiratory fitness at the end of 6 months. Six months of active intervention are followed by 18 months of a tapered follow-up maintenance intervention in both groups. Primary outcome measures are measured after 6 and 24 months.

Adult↗

Six-month physical activity and fitness changes in Project Active, a randomized trial.

PURPOSE: Project Active is a randomized clinical trial (N = 235) comparing a lifestyle physical activity program with a structured exercise program in changing physical activity (total energy expenditure [kcal.kg-1.d-1]) and cardiorespiratory fitness (VO2peak in mL.kg-1.min-1). METHODS: Sedentary but healthy adults (N = 235) aged 35-60 years received 6 months of intensive intervention. RESULTS: Analysis of covariance (ANCOVA), adjusting for baseline measure, age, gender, body mass index (BMI), cohort, and ethnicity, showed that at 6 months both lifestyle and structured groups significantly increased energy expenditure over baseline (P < 0.001). The mean increases +/- SE, 1.53 +/- 0.19 kcal.kg-1.d-1 for the lifestyle group and 1.34 +/- 0.20 kcal.kg-1 d-1 for the structured group, were not significantly different between groups (P = 0.49). For cardiorespiratory fitness, both groups had significant increases from baseline (P < 0.001). Mean increases +/- SE were 1.58 +/- 0.33 mL.kg-1.min-1 and 3.64 +/- 0.33 mL.kg-1.min-1 for the lifestyle and structured groups, respectively. This was significantly greater in the structured group (P < 0.001). We also studied changes in intensity of physical activity. Both groups significantly increased moderate intensity activity from baseline, but the increase was significantly greater in the lifestyle group than the structured group (P = 0.02). In contrast, the structured group increased its hard activity more than the lifestyle group, but the difference was not significantly different (P = 0.02). In contrast, the structured group increased its hard increased (P < 0.01) for both groups by 0.25 kcal.kg-1.d-1. CONCLUSION: Both intervention approaches are effective for increasing physical activity and fitness over a 6-month period in initially sedentary men and women.

Adult↗

Overview of the Activity Counseling Trial (ACT) intervention for promoting physical activity in primary health care settings. Activity Counseling Trial Research Group.

Counseling by health care providers has the potential to increase physical activity in sedentary patients, yet few studies have tested interventions for physical activity counseling delivered in health care settings. The Activity Counseling Trial (ACT) is a 5-yr randomized clinical trial to evaluate the efficacy of two primary care, practice-based physical activity behavioral interventions relative to a standard care control condition. A total of 874 sedentary men and women, 35-75 yr of age, have been recruited from primary care physician offices at three clinical centers for 2 yr of participation. They were randomly assigned to one of three experimental conditions that vary, in a hierarchical fashion, by level of counseling intensity and resource requirements. The interventions, which are based on social cognitive theory and the transtheoretical model, are designed to alter empirically based psychosocial mediators that are known to be associated with physical activity. The present paper describes the theoretical background of the intervention, the intervention methods, and intervention training and quality control procedures.

Adult↗

Activity Counseling Trial (ACT): rationale, design, and methods. Activity Counseling Trial Research Group.

The Activity Counseling Trial (ACT) is a multicenter, randomized controlled trial to evaluate the effectiveness of interventions to promote physical activity in the primary health care setting. ACT has recruited, evaluated, and randomized 874 men and women 35-75 yr of age who are patients of primary care physicians. Participants were assigned to one of three educational interventions that differ in amount of interpersonal contact and resources required: standard care control, staff-assisted intervention, or staff-counseling intervention. The study is designed to provide 90% power in both men and women to detect a 1.1 kcal.kg-1.day-1 difference in total daily energy expenditure between any two treatment groups, and over 90% power to detect a 7% increase in maximal oxygen uptake, the two primary outcomes. Primary analyses will compare study groups on mean outcome measures at 24 months post-randomization, be adjusted for the baseline value of the outcome measure and for multiple comparisons, and be conducted separately for men and women. Secondary outcomes include comparisons between interventions at 24 months of factors related to cardiovascular disease (blood lipids/lipoproteins, blood pressure, body composition, plasma insulin, fibrinogen, dietary intake, smoking, heart rate variability), psychosocial effect, and cost-effectiveness, and at 6 months for primary outcome measures. ACT is the first large-scale behavioral intervention study of physical activity counseling in a clinical setting, includes a generalizable sample of adult men and women and of clinical setting, and examines long-term (24 months) effects. ACT has the potential to make substantial contributions to the understanding of how to promote physical activity in the primary health care setting.

Adult↗