Resistance exercise in men receiving androgen deprivation therapy for prostate cancer.

PURPOSE: Androgen deprivation therapy is a common treatment in men with prostate cancer that may cause fatigue, functional decline, increased body fatness, and loss of lean body tissue. These physical changes can negatively affect health-related quality of life. Resistance exercise may help to counter some of these side effects by reducing fatigue, elevating mood, building muscle mass, and reducing body fat. METHODS: In a two-site study, 155 men with prostate cancer who were scheduled to receive androgen deprivation therapy for at least 3 months after recruitment were randomly assigned to an intervention group that participated in a resistance exercise program three times per week for 12 weeks (82 men) or to a waiting list control group (73 men). The primary outcomes were fatigue and disease-specific quality of life as assessed by self-reported questionnaires after 12 weeks. Secondary outcomes were muscular fitness and body composition. RESULTS: Men assigned to resistance exercise had less interference from fatigue on activities of daily living (P =.002) and higher quality of life (P =.001) than men in the control group. Men in the intervention group demonstrated higher levels of upper body (P =.009) and lower body (P <.001) muscular fitness than men in the control group. The 12-week resistance exercise intervention did not improve body composition as measured by changes in body weight, body mass index, waist circumference, or subcutaneous skinfolds. CONCLUSION: Resistance exercise reduces fatigue and improves quality of life and muscular fitness in men with prostate cancer receiving androgen deprivation therapy. This form of exercise can be an important component of supportive care for these patients.

Low cardiorespiratory fitness is associated with elevated C-reactive protein levels in women with type 2 diabetes.

OBJECTIVE: The purpose of this study was to examine differences in novel markers of cardiovascular disease (CVD) in women with type 2 diabetes stratified according to cardiorespiratory fitness. RESEARCH DESIGN AND METHODS: A total of 28 women (mean age 57 +/- 6 years) with type 2 diabetes who were free from overt CVD were placed into low cardiorespiratory fitness (LCF) or average cardiorespiratory fitness (ACF) groups based on a graded exercise test to exhaustion. A group of eight women without type 2 diabetes were also examined and served as healthy control subjects. The median VO(2peak) value was used as a cutoff for group determination. We assessed both conventional CVD risk factors, including blood pressure, BMI, and lipid profile, as well as novel CVD risk factors, such as left ventricular filling dynamics, arterial stiffness, fasting insulin, and C-reactive protein (CRP). RESULTS: VO(2peak) values were 69 +/- 14 and 91 +/- 24% of predicted values for sedentary age-matched healthy individuals in the LCF and ACF groups, respectively. BMI was significantly greater in the LCF group (P < 0.05); however, no differences were observed in age, lipid profile, or resting hemodynamics. CRP was 3.3-fold higher in the LCF group (6.3 +/- 41. vs. 1.9 +/- 1.7 mg/l, P < 0.05), whereas other novel markers of CVD were not significantly different between the groups. Significant negative relationships were observed between VO(2peak) and both CRP (r = -0.49) and the homeostasis model assessment index (r = -0.48) (P < 0.05). CONCLUSIONS: The novel finding of this investigation is that low cardiorespiratory fitness is associated with elevated CRP and reduced fasting glucose control in women with type 2 diabetes.

Three independent factors predicted adherence in a randomized controlled trial of resistance exercise training among prostate cancer survivors.

OBJECTIVE: To examine predictors of adherence in a randomized controlled trial of resistance exercise training (RET) in prostate cancer survivors receiving androgen deprivation therapy. STUDY DESIGN AND SETTING: A randomized controlled trial conducted at fitness centers in Ottawa and Edmonton, Canada. Prostate cancer survivors (n=155) completed measures of social cognitive variables, quality of life (QOL), behavior, and fitness before being randomized to either an exercise (n=82) or control (n=73) group. The exercise group was asked to perform supervised RET three times per week for 12 weeks. RESULTS: The exercise group attended 28.2 of the 36 (78.3%) RET sessions. Univariate analyses revealed eight different significant (Ps <.05) predictors of exercise adherence including exercise stage of change, intention, age, QOL, fatigue, subjective norm, leg-press test, and perceived behavioral control. A multivariate analysis indicated that there were three independent predictors of adherence that explained 20.4% of the variance: exercise stage of change (beta=0.26; P=.013), age (beta=-0.22; P=.037), and intention (beta=0.19; P=.073). CONCLUSION: Exercise adherence in the trial was very good but not optimal. Adherence was predicted by variables from many different categories including social cognitive, QOL, behavioral, fitness, and demographic. These findings may have important implications for maximizing adherence during clinical trials of exercise in prostate cancer survivors.

The role of exercise in the treatment of cardiovascular disease associated with type 2 diabetes mellitus.

The role of exercise training in the prevention and treatment of type 2 diabetes mellitus has been studied extensively over the past two decades. Although the primary treatment aim for patients with type 2 diabetes is metabolic control, the morbidity and mortality associated with the disease is more a function of cardiovascular disease. As exercise is associated with favourable reductions in the risk for cardiovascular disease in other high-risk populations, here we explore the role of exercise in the treatment of cardiovascular maladaptations associated with type 2 diabetes. The cardiovascular adaptation to type 2 diabetes is characterised by hypertrophy, stiffening and loss of functional reserve. Clinically, the cardiovascular adaptations to the diabetic state are associated with an increased risk for cardiovascular disease. Functionally, these adaptations have been shown to contribute to a reduced exercise capacity, which may explain the reduced cardiovascular fitness observed in this population. Exercise training is associated with improved exercise capacity in various populations, including type 2 diabetes. Several structural and functional adaptations within the cardiovascular system following exercise training could explain these findings, such as reductions in ventricular and vascular structural hypertrophy and compliance coupled with increased functional reserve. Although these cardiovascular adaptations to aerobic exercise training have been well documented in older populations with similar decrements in cardiovascular fitness and function, they have yet to be examined in patients with type 2 diabetes. For this reason, we contend that exercise training may be an excellent therapeutic adjunct in the treatment of diabetic cardiovascular disease.

Effects of taper on endurance cycling capacity and single muscle fiber properties.

PURPOSE: It was hypothesized that metabolic adaptations in single muscle cells after a taper period are fiber type (I and II) specific and protocol regimen dependent. METHODS: After 7-wk intensive endurance training, 22 male cyclists (VO2max=4.42 +/- 0.40 L.min(-1)) were randomly assigned to one of three 7-d taper groups: the control group (CON, N=7) continued weekly training, the first experimental group (INT) maintained training intensity but reduced duration (N=7), and the second experimental group (DUR) maintained training duration but reduced exercise intensity (N=8). Each cyclist completed a simulated 40-km time trial (40TT) before and after tapering on a set of wind-loaded rollers using their own bicycle. Muscle biopsies were taken immediately before the 40TT both before and after tapering, and analyzed for mATPase, succinate dehydrogenase (SDH), cyctochrome oxidase (CYTOX), alpha-glycerolphosphate dehydrogenase (alpha-GPD), and beta-hydroxyacyl CoA dehydrogenase (beta-HOAD) in Type I and II fibers, separately, using quantitative histochemistry. RESULTS: The results showed significant (P< or =0.05) increases in SDH (Type I) and mATPase, CYTOX, beta-HOAD, and SDH (Type II fibers) in the INT group, and significant increases in CYTOX (Type I) and beta-HOAD (Type I and II fibers) in the DUR group. Regression analysis showed that the change (posttaper minus pretaper) in simulated 40-km endurance time was correlated with the change in CYTOX and SDH activity for all groups combined (r2=0.62-0.72). CONCLUSION: These results demonstrated that the metabolic properties of different fiber types are altered with tapering, that the type of taper protocol used influences their physiological adaptation, and that improvements in simulated 40-km endurance time were related to changes in metabolic properties of the muscle at the single fiber level.

Blood volume expansion and cardiorespiratory function: effects of training modality.

PURPOSE: To evaluate the effects of different modalities of aerobic (i.e., interval (INT) and continuous (CONT)) training on cardiorespiratory function and the importance of training-induced blood volume (BV) expansion on aerobic power and LV function. We hypothesized that if modality-mediated differences in cardiorespiratory function exist after INT and CONT, they would be related directly to differences in training-induced hypervolemia. METHODS: We examined the effects of 12 wk of CONT and INT on BV, volume-regulatory hormones (angiotensin II, aldosterone, atrial natriuretic peptide), and cardiorespiratory function in 20 untrained males (mean age 30 +/- 4 (SD)). Participants were stratified (mass and VO2max) and randomly assigned to control, CONT, or INT. RESULTS: There were no significant changes in cardiorespiratory function or BV in the control group. Twelve weeks of continuous and interval training, respectively, resulted in significant changes in VO2max (23 +/- 18 vs 21 +/- 10%), peak stroke volume (20 +/- 18 vs 11 +/- 18%), and BV (12 +/- 9 vs 10 +/- 6%). Changes in VO2max were directly related to changes in BV (r = 0.47). Angiotensin II significantly increased after 1 wk of CONT and INT and thereafter returned to baseline values. There was no significant difference between the CONT and INT groups with regard to changes in vascular volumes, volume-regulatory hormones, and/or cardiorespiratory function. CONCLUSIONS: These data indicate that: 1) 12 wk of CONT and INT result in similar improvements in VO2max, and LV function and 2) training-induced hypervolemia accounts for approximately 47% of the changes in VO2max after CONT and INT.

Effects of aerobic or aerobic and resistance training on cardiorespiratory and skeletal muscle function in heart failure: a randomized controlled pilot trial.

OBJECTIVE: To examined the effects of different training modalities on exercise capacity (Vo( 2peak)), systolic function, muscular strength and endurance and quality of life in heart failure patients. DESIGN: Randomized controlled trial. SETTING: Cardiac rehabilitation centre in Canada. SUBJECTS: Forty-two individuals with heart failure (62 +/- 12 years; New York Heart Association (NYHA) classes I-III). INTERVENTIONS: Aerobic training (n = 14), combined aerobic and resistance training (n = 15) or usual care (n = 13) three times per week for 12 weeks. MAIN MEASURES: (1) Vo( 2peak) measured by symptom-limited graded exercise test on cycle ergometer; (2) systolic function assessed by two-dimensional echocardiography; (3) muscular strength and muscular endurance measured by one-repetition maximum procedure; and (4) quality of life assessed by questionnaires. RESULTS: In the intention-to-treat analysis, neither aerobic nor combined aerobic and resistance training significantly improved Vo(2peak), systolic function or quality of life compared with usual care. However, combined aerobic and resistance training significantly improved upper extremity strength (40.7 (14.0)-48.5 (16.0) kg, P<0.05) and muscular endurance (5.7 (2.7)-11.6 (7.6) reps, P<0.05) compared with aerobic training or usual care. In compliant participants (exercise adherence 80%), Vo(2peak) increased in the aerobic group (16.9 (6.0)-19.0 (6.8), P= 0.026) and tended to increase in the combined training group (15.9 (5.0)-17.6 (5.6), P= 0.058) compared with usual care. Quality of life was improved in the aerobic group only. CONCLUSIONS: Both aerobic and combined aerobic and resistance training are effective interventions to improve Vo(2peak) in compliant heart failure patients. Combined training may be more effective in improving muscle strength and endurance.

A longitudinal study of exercise barriers in colorectal cancer survivors participating in a randomized controlled trial.

BACKGROUND: The Colorectal Cancer and Home-Based Physical Exercise (CAN-HOPE) trial compared the effects of a 16-week home-based exercise program to usual care on quality of life in colorectal cancer survivors. PURPOSE: In this study, we report the weekly exercise barriers from the exercise group. METHODS: Participants randomized to the exercise group (N = 69) were asked to report their exercise on a weekly basis by telephone. Those participants not achieving the minimum weekly exercise prescription (3 times per week of 30 min of moderate intensity exercise) were asked for a primary exercise barrier. RESULTS: We obtained 1,073 (97.2%) weeks of adherence data out of a possible 1,104 (i.e., 69 x 16). Participants did not meet the minimum exercise prescription in 39.2% (421/1,073) of the weeks. We obtained an exercise barrier in 83.8% (353/421) of these cases. Overall, participants reported 37 different exercise barriers; the three most common were lack of time/too busy, nonspecific treatment side effects, and fatigue. The top 7 to 10 barriers accounted for 70% to 80% of all missed exercise weeks. CONCLUSIONS: These findings may have utility for promoting exercise in this population both inside and outside of clinical trials.

Correlates of adherence and contamination in a randomized controlled trial of exercise in cancer survivors: an application of the theory of planned behavior and the five factor model of personality.

In this study, we examined correlates of adherence and contamination in a randomized controlled trial (RCT) of exercise in cancer survivors using the theory of planned behavior and the Five Factor Model of personality (FFM). We randomly assigned cancer survivors in group psychotherapy classes to either a waiting-list control group (n = 45) or a home-based, moderate intensity exercise program (n = 51). At baseline, participants completed measures of the theory of planned behavior, the FFM, past exercise, physical fitness, medical variables, and demographics. We then monitored exercise over a 10-week period by weekly self-reports. Hierarchical multiple regression analyses indicated that the independent predictors of overall RCT exercise across both conditions were past exercise (beta = .36, p < .001), assignment to experimental condition (beta = .34, p < .001), sex (beta = .30, p < .001), and intention (beta = .14, p < .10). For exercise adherence in the exercise condition, the independent predictors were sex (beta = .38, p < .01), extraversion (beta = .30, p < .05), normative beliefs (beta = -.27, p < .05), and perceived behavioral control (beta = .23, p < .10). Finally, the independent predictors of exercise contamination in the control condition were past exercise (beta = .70, p < .001), sex (beta = .20, p < .05), and intention (beta = .17, p < .10). We conclude that the correlates of exercise adherence and contamination differ in kind as well as in degree. Explanations for these findings and practical implications for conducting exercise RCTs in this population are offered.

Myocardial response to incremental exercise in endurance-trained athletes: influence of heart rate, contractility and the Frank-Starling effect.

Recent evidence indicates that endurance-trained athletes are able to increase their stroke volume (SV) throughout incremental upright exercise, probably due to a progressively greater effect of the Frank-Starling mechanism. This is contrary to the widely held belief that SV reaches a plateau at a submaximal heart rate (irrespective of fitness level), owing to a limitation in the time for diastolic filling. The purpose of this investigation was to evaluate whether endurance-trained athletes rely on a progressively greater effect of the Frank-Starling mechanism throughout incremental exercise. A secondary purpose was to evaluate the effects of postural position on the cardiovascular responses to incremental exercise. Ten male cyclists participated in this investigation. Left ventricular function was assessed throughout incremental exercise in the supine and upright positions (counterbalanced) using radionuclide ventriculography. Stroke volume increased in a linear fashion during incremental exercise in both the upright and supine positions. The increases in cardiac output (Q) throughout incremental to maximal exercise (in both the supine and upright positions) were significantly related to changes in heart rate, myocardial contractility and the Frank-Starling mechanism. Percentage changes in end-diastolic volume and SV were significantly greater in the upright position versus the supine position, reflecting an increased reliance on the Frank-Starling effect to increase Q. We conclude from this investigation that highly trained endurance athletes are able to make progressively increasing usage of the Frank-Starling effect throughout incremental exercise. Postural position has a significant effect on the relative contribution of heart rate, myocardial contractility and the Frank-Starling mechanism to the increase in Q during exercise conditions.

Exercise motivation and adherence in cancer survivors after participation in a randomized controlled trial: an attribution theory perspective.

The purpose of this study was to examine postprogram exercise motivation and adherence in cancer survivors who participated in the Group Psychotherapy and Home-Based Physical Exercise (GROUP-HOPE; Courneya, Friedenreich, Sela, Quinney, & Rhodes, 2002) trial. At the completion of the GROUP-HOPE trial, 46 of 51 (90%) participants in the exercise group completed measures of attribution theory constructs. A 5-week follow-up self-report of exercise was then completed by 30 (65%) participants. Correlational analyses indicated that program exercise, perceived success, expected success, and affective reactions were strong predictors of postprogram exercise. In multivariate stepwise regression analyses, program exercise and perceived success were the strongest predictors of postprogram exercise. Additionally, perceived success was more important than objective success in understanding the attribution process, and it interacted with personal control to influence expected success and negative affect. Finally, postprogram quality of life and changes in physical fitness were correlates of perceived success. We concluded that attribution theory may have utility for understanding postprogram exercise motivation and adherence in cancer survivors.

The group psychotherapy and home-based physical exercise (group-hope) trial in cancer survivors: physical fitness and quality of life outcomes.

Physical exercise has been shown to enhance quality of life (QOL) in cancer survivors using pretest-posttest designs and compared to usual care (i.e. no intervention). In the present study, we conducted a randomized controlled trial to determine if exercise could improve QOL in cancer survivors beyond the known benefits of group psychotherapy (GP). We matched 22 GP classes (N=108) on content and then randomly assigned 11 (n=48) to GP alone and 11 (n=60) to GP plus home-based, moderate-intensity exercise (GP+EX). Participants completed a physical fitness test and QOL measures (e.g. Functional Assessment of Cancer Therapy scales) at the beginning and end of GP classes (about 10 weeks). We had excellent recruitment (81%), retention (89%), and adherence (84%) rates and a modest contamination (22%) rate. Using intention-to-treat repeated measures analyses of variance, we found significant Time by Condition interactions for functional well-being, fatigue, and sum of skinfolds. We also found borderline significant interactions for physical well-being, satisfaction with life, and flexibility. All interactions favored the GP+EX condition. We conclude that a home-based, moderate intensity exercise program may im-prove QOL in cancer survivors beyond the benefits of GP, particularly in relation to physical and functional well-being.

Predictors of adherence and contamination in a randomized trial of exercise in colorectal cancer survivors.

The purpose of this study was to examine predictors of exercise adherence (i.e. exercise in the intervention group) and exercise contamination (i.e. exercise in the control group) in a randomized controlled trial of home-based exercise in colorectal cancer survivors. At baseline, 102 participants completed measures of the theory of planned behavior, personality, past exercise, exercise stage of change, physical fitness, and medical/demographics and then were randomly assigned in a 2:1 ratio to an exercise (n=69) or control (n=33) group. Exercise was monitored weekly for 16 weeks using self-reports by telephone. Ninety-three (91%) participants completed the trial. Adherence was 76% in the exercise group and contamination was 52% in the control group. Hierarchical stepwise regression analyses indicated that baseline exercise stage of change (beta=0.35; p=0.001), employment status (beta=-0.28; p=0.010), treatment protocol (beta=-0.26; p=0.018), and perceived behavioral control (beta=0.20; p=0.055) explained 39.6% of the variance in exercise adherence. Intentions (beta=0.36; p=0.049) and baseline exercise stage of change (beta=0.30; p=0.095) explained 29.9% of the variance in exercise contamination. These findings may have implications for conducting clinical trials of exercise in colorectal cancer survivors and for promoting exercise to colorectal cancer survivors outside of clinical trials.

Late potentials in female triathletes before and after prolonged strenuous exercise.

The objectives of this study were to evaluate the prevalence of late potentials (LP) in female triathletes before and after prolonged strenuous exercise (PSE), and to determine whether LP are related to greater left ventricular (LV) dimensions and/or mass. Thirteen female triathletes were examined immediately before (Pre), one hour after (Post), and 24 to 48 hours after PSE (Recovery) using signal-averaged electrocardiography (SAECG). Late potentials were evaluated by two or more standard SAECG anomalies. Left ventricular dimensions and mass were measured Pre using two-dimensional echocardiography. Results revealed that no significant differences existed between Pre, Post, and Recovery in the SAECG parameters. Four athletes displayed LP during Pre. The incidence of LP during did not increase Post. There were no significant relationships between LV dimensions or mass and SAECG parameters. In conclusion, a small portion of female triathletes display LP before and after PSE, which are not worsened by PSE nor related to increased LV dimensions and/or mass.