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Purpose. Current cardiac rehabilitation (CR) evidence was systematically evaluated to identify program components that may yield improvements in physiological and psychosocial outcomes in women. Methods. A search was conducted in the electronic databases: MEDLlNE, Embase, ClNAHL, Scopus, Sport Discus and Cochrane Library. Search terms included women, heart disease, exercise therapy, and cardiac rehabilitation. A systematic elimination process was used with specific inclusion/exclusion criteria. Included articles were independently evaluated by four reviewers for level of evidence and internal validity. Specific recommendations were made based on trends in the literature and strength of supporting evidence. Results. Thirty-seven articles were included with a combined sample of 3,807 Subjects. Ten studies included an analysis of physiological effects of exercise. Aerobic, resistance, and combined exercise interventions all yield physiological benefits. CR yielded favourable healthrelated quality of life outcomes and women benefited from psychosocial support in both formal and informal environments. Conclusions. The following recommendations are based on the review: 1) For patients with good cardiac function, community/home-based programs are as effective as supervised programs (Level II, B); 2) resistance training should be included as an adjunct to aerobic training (Level I, A); 3) programs need to address the specific educational needs of women (Level I, A) and a stronger emphasis needs to be placed on social support (Level II, B). [ABSTRACT FROM AUTHOR]

Purpose. To examine cardiovascular function and risk profile of postmenopausal women treated with chemoendocrine therapy (CET) for hormone receptor-positive operable breast cancer. Methods. Forty-seven breast cancer patients and 11 age-matched healthy controls were studied. Participants performed a cardiopulmonary exercise test with expired gas analysis and impedance cardiography to assess peak aerobic power (VO(2peak)) and cardiovascular function (stroke volume, cardiac output, cardiac power output, and cardiac reserve). Traditional (i.e., body mass index, lipid profile, and fasting insulin and glucose) and novel (i.e., C-reactive protein, brain natriuretic peptide) cardiovascular risk biochemical factors were also assessed. Results. Breast cancer patients had significantly lower peak exercise stroke volume (68 +/- 9 versus 76 +/- 11 ml/beat), cardiac output (10.4 +/- 1.5 versus 11.7 +/- 2.4 l/minute), cardiac power output (3.0 +/- 0.5 versus 3.5 +/- 0.9 Watts), cardiac power output reserve (1.7 +/- 0.6 versus 2.4 +/- 0.8 Watts), and VO(2peak) (1.3 +/- 0.3 versus 1.6 +/- 0.2 l.min(-1)) than control subjects (p-values < .05). Patients with the greatest impairment in VO(2peak) had the worse cardiovascular risk profile. Exploratory analyses revealed several differences in study outcomes between the 26 patients receiving hormonal therapy with tamoxifen (TAM) and the 21 patients receiving aromatase inhibitor (AI) therapy. Conclusion. Breast cancer patients treated with adjuvant CET have a significantly and markedly lower cardiorespiratory fitness and cardiac functional reserve compared with age- and sex-matched controls. AI therapy may be associated with a more unfavorable cardiovascular risk profile than TAM. Prospective studies are required to further investigate the clinical value of these findings. [ABSTRACT FROM AUTHOR]

Background: There is a deleterious association between sedentary behavior and mortality risk factors. Elevated sedentary time has been reported in several studies that involved cardiac rehabilitation (CR) participants., Objectives: To examine the changes in sedentary behavior, breaks in sedentary time, and physical activity (PA) in CR participants., Methods: This was a prospective repeated measures study. Sedentary behavior and PA were assessed using accelerometer at baseline, 12 weeks, and 6 months after CR entry., Results: At 12 weeks, participants (n = 58) spent more time in moderate-vigorous PA (MVPA) and tended to be less sedentary. However, the changes were lost by 6 month follow-up. Although the majority of participants met the recommended MVPA, our participants demonstrated elevated sedentary time. We found a strong positive correlation between time in light PA and number of breaks in sedentary time; neither of which showed any changes over time., Conclusions: By promoting MVPA as their main target, current CR programs may have little impact on changing the elevated sedentary behavior of their participants. Further, interrupting sedentary time with light PA could be an achievable strategy to reduce sedentary behavior in CR participants., (Copyright © 2018. Published by Elsevier Inc.)

Purpose: Cardiac resynchronization therapy (CRT) has emerged as a beneficial therapy for heart failure (HF) patients. It has been shown to enhance cardiac pump function and increase exercise capacity in patients with HF who display wide QRS complex on their electrocardiogram. To date, few studies have assessed daily physical activity (PA) in CRT patients. The objective of this pilot study was to assess the impact of CRT on the physical function and daily PA of HF patients who met the standard indications for CRT implantation., Methods: The daily PA of 18 CRT patients was measured using a SenseWear Armband for ∼3 d. Daily PA measurements included steps/d and time spent sedentary (≤1.5 metabolic equivalent tasks), in light PA (1.6-2.9 metabolic equivalent tasks), and in moderate-vigorous PA (≥3 metabolic equivalent tasks). To assess exercise capacity, a 6-min walk test was performed pre- and post-CRT., Results: There was no significant change in the 6-min walk test distance from pre- to post-CRT (383 ± 99 m at baseline vs 402 ± 104 m post-CRT). There was a decrease in total steps/d from 3405 ± 2334 pre-CRT to 2553 ± 1692 post-CRT (P = .017). Furthermore, no significant changes were observed pre- to post-CRT with regard to the additional PA assessments., Conclusions: Our patients exhibited a sedentary lifestyle pre- and post-CRT. These findings underscore the need for a cardiac rehabilitation program that encourages post-CRT patients to decrease sedentary time.

Background: The benefits of regular physical activity (PA) are well documented in patients with heart failure (HF), however the amount and intensity of objectively measured PA and sedentary behaviour in HF with preserved (HFPEF) or reduced ejection fraction (HFREF) is not well known., Methods: In a cross-sectional observational study the energy expenditure of 151 participants (HFPEF: n = 53; HFREF: n = 16; at-risk for HF: n = 48; control participants: n = 34) using SenseWear Mini Armbands (Body Media, Inc, Pittsburgh, PA) were monitored. PA outcomes included time spent in different PA intensities (light and moderate-vigorous PA), sedentary time, steps per day, total daily energy expenditure, PA energy expenditure, and the patterns of PA in bouts of ≥ 10 minutes of moderate-vigorous PA., Results: The patients with HFPEF had the lowest volume of activity across the 4 groups. After adjusting for covariates, only steps per day remained significantly different across groups (P = 0.0005). A comparison of HFPEF vs HFREF indicated a higher amount of time in bouts of ≥ 10 minutes of moderate-vigorous PA for patients with HFREF (median, 2.4 [interquartile range, 0-13.5] vs 26 [3.7-46.8]; P = 0.0075). In the at-risk group, PA was lower than the recommended levels in the guidelines., Conclusions: Our findings suggest step count as the most robust outcome in evaluating daily PA in this population. Also, patients with HFPEF showed to be the least active group in the HF continuum. Monitoring volume and pattern of PA for those at risk of HF and patients with HFPEF could help to identify sedentary individuals and to develop tailored behavioural interventions for them., (Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Despite the health benefits associated with regular physical activity (PA), many cardiac patients fail to maintain optimal levels of PA after completing cardiac rehabilitation (CR). The long-term impact of different CR delivery models on the PA habits of cardiac patients is not completely understood., Objective: The purpose of this study is to use a multisensor accelerometer to compare the long-term impact of a traditional versus fast-track CR on the PA of patients with coronary artery disease 6 months after CR entry., Methods: Forty-four participants attended either traditional (twice a week, 12 weeks; n = 24) or fast-track (once a week, 8 weeks; n = 20) CR. Exercise capacity (ie, 6-minute walk test distance) and PA were assessed at baseline and at 12 weeks and 6 months after CR entry., Results: At 12 weeks, exercise capacity increased significantly in both groups and remained elevated by the 6-month follow-up. Sedentary time decreased from baseline to 12 weeks. However, at 6 months, it was comparable with the baseline level. There was no significant change in any other PA marker (ie, steps/day, time in light and moderate-vigorous PA) over the course of the study., Conclusions: Findings support the long-term effectiveness of CR on exercise capacity irrespective of the delivery model. However, participation in CR program, whether it be a traditional or fast-track CR exercise program, may not lead to long-term PA behavior change. Thus, CR participants may benefit from structured strategies that promote long-term PA adherence in addition to facilitating exercise capacity improvement.

Background: Sedentary behaviour and the level of daily physical activity are of particular concern in cardiac patients, as diminished activity may be a strong predictor of mortality in this population., Purpose: In this study we assessed sedentary behaviour and the quantity and quality of daily physical activity among older cardiac patients who were at different stages of recovery following a cardiac event., Design: We used a cross-sectional design and a convenience sampling technique., Method: Participants were recruited into three groups: an Acute group (n = 32), a Rehab group (n = 32), and a Maintain group (n = 29). Continuous minute by minute physical activity was assessed using the SenseWear Mini Armband, which was worn throughout each day for four consecutive days and provided data on steps/day, as well as time spent sedentary (waking time ≤ 1.5 METs), or in light (1.6-2.9 METs) or moderate-vigorous (≥ 3.0 METs) physical activity., Findings: While the Rehab group accumulated more daily activity than the other two groups, they remained sedentary for approximately 70% of waking time. The quantity and quality of the activity in the Maintain group was comparable to that observed in the Acute group., Conclusions: Our observation of consistently elevated sedentary time regardless of whether the participant was entering, completing or were long removed from a formal cardiac rehabilitation program reinforces the need for cardiac rehabilitation nurse educators to both monitor routine daily activity and encourage coronary artery disease patients to adapt a lifestyle that is focused on reducing sedentary behaviour by incorporating planned exercise training and unstructured physical activity throughout the day.

Objectives: The purpose of this study was to assess the impact of exercise rehabilitation (ER) on the daily physical activity (PA) of cardiopulmonary patients., Background: The impact of ER programs on the objectively measured quantity and quality of daily PA in cardiopulmonary patients is not completely understood., Methods: Participants' exercise capacity and PA were measured at baseline and at the end of the ER program (n = 37)., Results: Exercise capacity was higher at the end of the ER. Participants' sedentary time decreased while time spent in light PA increased; however, time spent in moderate-vigorous PA (MVPA) did not change. There was an increase in steps/day (>1.5 METs) and PA energy expenditure (PAEE) (>1.5 METs); whereas steps/day (≥3METs) and PAEE (≥3 METs) remained unchanged., Conclusions: Findings imply that changes in daily PA in patients participating in ER occur in activities where the EE is in light intensity rather than in MVPA., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: Although participation in either center- or home-based cardiac rehabilitation (CR) can improve exercise capacity, the sustainability of this improvement following completion of the CR program is challenging. The purpose of this study was to compare the immediate and 1-year effectiveness of center- versus home-based CR on exercise capacity in cardiac patients who were given the choice of participating in a center-based or home-based CR program., Methods: This was a retrospective study, which relied on the database from a large multidisciplinary CR program. A sample of 3488 cardiac patients participated either in center-based (n = 2803) or home-based (n = 685) CR. Participants underwent exercise testing at baseline, after 12 weeks of CR and again 1 year after completion of the CR programs., Results: Following CR, exercise capacity (ie, peak metabolic equivalents [METs]) increased significantly in both groups (P < .05). From post-CR to the 1-year followup, exercise capacity remained unchanged in home-based CR participants (P = .183), whereas the center-based CR group demonstrated a decline in exercise capacity (P < .05)., Conclusions: Although at the 1-year followup exercise capacity decreased in the center-based group, the observed decline did not seem to be clinically significant. The present findings indicate that when the patients were given a choice as to the delivery model (center- vs home-based) used for their CR program, they were relatively successful in retaining the improvement in exercise capacity 1 year post-CR irrespective of the exact location for their exercise training.

Techniques to increase physical activity among pulmonary rehabilitation patients outside of the rehabilitation context are warranted. Implementation intentions are a strategy used to initiate goal-directed behaviour, and have been found to be useful in other populations. This study compared the long-term effects of exercise and social implementation intentions interventions on objectively measured physical activity in 40 pulmonary rehabilitation patients randomly assigned to condition. Repeated measures ANOVAs found that those in the exercise implementation intentions group took more steps (p = .007) at the end of pulmonary rehabilitation than those in the social implementation intentions group. Improvements attained by the exercise group during the intervention were not maintained 6-months following rehabilitation. Implementation intentions targeting physical activity appear to have positive short term effects on physical activity, although the long term effects are less consistent. This may be due in part to methods used to assess physical activity behaviour.

Exercise training improves health-related physical fitness and patient-reported outcomes in cancer survivors, but few interventions have targeted colorectal cancer (CRC) survivors. This investigation aimed to determine the feasibility and efficacy of a 12-week supervised exercise training program for CRC survivors. Feasibility was assessed by tracking participant recruitment, loss to follow-up, assessment completion rates, participant evaluation, and adherence to the intervention. Efficacy was determined by changes in health-related physical fitness. Over a 1-year period, 72 of 351 (21%) CRC survivors screened were eligible for the study and 29 of the 72 (40%) were enrolled. Two participants were lost to follow-up (7%) and the completion rate for all study assessments was ≥93%. Mean adherence to the exercise intervention was 91% (standard deviation = ±18%), with a median of 98%. Participants rated the intervention positively (all items ≥ 6.6/7) and burden of testing low (all tests ≤ 2.4/7). Compared with baseline, CRC survivors showed improvements in peak oxygen uptake (mean change (MC) = +0.24 L·min(-1), p < 0.001), upper (MC = +7.0 kg, p < 0.001) and lower (MC = +26.5 kg, p < 0.001) body strength, waist circumference (MC = -2.1 cm, p = 0.005), sum of skinfolds (MC = -7.9 mm, p = 0.006), and trunk forward flexion (MC = +2.5 cm, p = 0.019). Exercise training was found to be feasible and improved many aspects of health-related physical fitness in CRC survivors that may be associated with improved quality of life and survival in these individuals.

Renal transplant recipients (RTR) have reduced peak aerobic capacity, muscle strength, arterial function and an unfavorable cardiovascular disease risk (CVD) profile. This study compared the effects of 12 weeks of supervised endurance and strength training (EST, n = 16) versus usual care (UC, n = 15) on peak aerobic capicity, cardiovascular and skeletal muscle function, CVD risk profile, and quality of life (QOL) in RTR (55 ± 13 years). Peak aerobic capacity and exercise hemodynamics, arterial compliance, 24-h blood pressure, muscle strength, lean body mass, CVD risk score, and QOL were assessed before and after 12 weeks. The change in peak aerobic capacity (EST: 2.6 ± 3.1 vs. UC: -0.5 ± 2.5 mL/(kg·min)), cardiac output (EST: 1.7 ± 2.6 vs. UC: -0.01 ± 0.8 L/min), leg press (EST: 48.7 ± 34.1 vs. UC: -10.5 ± 37.7 kg) and leg extension strength (EST: 9.5 ± 10.3 vs. UC: 0.65 ± 5.5 kg) improved significantly after EST compared with UC. The overall change in QOL improved significantly after 12 weeks of EST compared with UC. No significant difference was found between groups for lean body mass, arterial compliance, 24-h blood pressure or CVD risk score. Supervised EST is an effective intervention to improve peak exercise aerobic capacity and cardiac output, muscle strength and QOL in clinically stable RTR.

The purpose of this study was to examine the physiological responses to treadmill and cycle cardiopulmonary exercise testing (CPET) in male and female COPD patients. Fifty-five patients [28 males (FEV1=58.2±19.5% predicted), and 27 females (FEV1=65.3±16.6% predicted)] completed a treadmill and a cycle CPET in random order on two separate days. Respiratory and cardiovascular data were obtained. Compared to the cycle CPET, the treadmill elicited greater peak power output and peak oxygen uptake, while arterial saturation at peak exercise was lower with the treadmill; however, there were no differences between the responses in men and women. No differences were observed in heart rate, ventilation, tidal volume/breathing frequency, inspiratory capacity, or dyspnea responses between modalities or sex. The physiological responses between treadmill and cycle CPET protocols are largely similar for both men and women with COPD, indicating that either modality can be used in mild/moderate COPD patients., (Copyright © 2013 Elsevier B.V. All rights reserved.)

In the past decade a significant development in the management and rehabilitation of people with chronic heart failure (CHF) has been the utilization of cardiac devices. The use of biventricular pacemakers, referred to as Cardiac Resynchronization Therapy (CRT) can yield improvements in functional abilities for a select group of CHF patients and the inclusion of implantable cardiac defibrillators (ICDs) may reduce the risk of sudden death. This review provides physical therapists with a basic understanding of how to prescribe exercise for people with CHF who have these device implants.

To better understand the mechanisms contributing to improved exercise capacity with cardiac resynchronization therapy (CRT), we studied the effects of 6 mo of CRT on pulmonary O(2) uptake (Vo(2)) kinetics, exercise left ventricular (LV) function, and peak Vo(2) in 12 subjects (age: 56 ± 15 yr, peak Vo(2): 12.9 ± 3.2 ml·kg(-1)·min(-1), ejection fraction: 18 ± 3%) with heart failure. We hypothesized that CRT would speed Vo(2) kinetics due to an increase in stroke volume secondary to a reduction in LV end-systolic volume (ESV) and that the increase in peak Vo(2) would be related to an increase in cardiac output reserve. We found that Vo(2) kinetics were faster during the transition to moderate-intensity exercise after CRT (pre-CRT: 69 ± 21 s vs. post-CRT: 54 ± 17 s, P < 0.05). During moderate-intensity exercise, LV ESV reserve (exercise - resting) increased 9 ± 7 ml (vs. a 3 ± 9-ml decrease pre-CRT, P < 0.05), and steady-state stroke volume increased (pre-CRT: 42 ± 8 ml vs. post-CRT: 61 ± 12 ml, P < 0.05). LV end-diastolic volume did not change from rest to steady-state exercise post-CRT (P > 0.05). CRT improved heart rate, measured as a lower resting and steady-state exercise heart rate and as faster heart rate kinetics after CRT (pre-CRT: 89 ± 12 s vs. post-CRT: 69 ± 21 s, P < 0.05). For peak exercise, cardiac output reserve increased significantly post-CRT and was 22% higher at peak exercise post-CRT (both P < 0.05). The increase in cardiac output was due to both a significant increase in peak and reserve stroke volume and to a nonsignificant increase in heart rate reserve. Similar patterns in LV volumes as moderate-intensity exercise were observed at peak exercise. Cardiac output reserve was related to peak Vo(2) (r = 0.48, P < 0.05). These findings demonstrate the chronic CRT-mediated cardiac factors that contribute, in part, to the speeding in Vo(2) kinetics and increase in peak Vo(2) in clinically stable heart failure patients.

The purpose of this study was to test the validity of the SenseWear Pro Armband (SWA) for the measurement of energy expenditure (EE) and step count against a criterion in persons with stroke. Twelve participants with chronic stroke (mean age 64.2 ± 10.4 years; mean gait speed 0.67 ± 0.25 m/sec) completed two trials of a six-minute walk test, while wearing a SenseWear Armband (SWA) on each arm and being continuously monitored using a portable metabolic cart. Agreement between estimates of energy expenditure from the SWA and the metabolic cart was fair for the armband on the hemiplegic arm (intraclass correlation cefficient (ICC) = 0.586) and good for the armband on the unaffected arm (ICC = 0.702). Agreement between the SWA estimate of step count, and step count as measured by the Step Activity Monitor was poor (ICC < 0.352), with significant underestimation by the SWA. Our results show that, for these moderately impaired persons with stroke, the SWA should be used with caution for the measurement of energy expenditure and should not be used to measure step count.

We studied the acute effect of high-intensity interval exercise on biventricular function using cardiac magnetic resonance imaging in nine patients [age: 49 ± 16 yr; left ventricular (LV) ejection fraction (EF): 35.8 ± 7.2%] with nonischemic mild heart failure (HF). We hypothesized that a significant impairment in the immediate postexercise end-systolic volume (ESV) and end-diastolic volume (EDV) would contribute to a reduction in EF. We found that immediately following acute high-intensity interval exercise, LV ESV decreased by 6% and LV systolic annular velocity increased by 21% (both P < 0.05). Thirty minutes following exercise (+30 min), there was an absolute increase in LV EF of 2.4% (P < 0.05). Measures of preload, left atrial volume and LV EDV, were reduced immediately following exercise. Similar responses were observed for right ventricular volumes. Early filling velocity, filling rate, and diastolic annular velocity remained unchanged, while LV untwisting rate increased 24% immediately following exercise (P < 0.05) and remained 18% above baseline at +30 min (P < 0.05). The major novel findings of this investigation are 1) that acute high-intensity interval exercise decreases the immediate postexercise LV ESV and increases LV EF at +30 min in patients with mild HF, and this is associated with a reduction in LV afterload and maintenance of contractility, and 2) that despite a reduction in left atrial volume and LV EDV immediately postexercise, diastolic function is preserved and may be modulated by enhanced LV peak untwisting rate. Acute high-intensity interval exercise does not impair postexercise biventricular function in patients with nonischemic mild HF.

Background: The effect of organ transplantation on arterial compliance, pulmonary oxygen uptake (VO2p) and heart rate kinetics during the 6-minute walk test (6-MWT) remains unknown., Methods: Twenty-two thoracic (heart and/or lung) organ transplant recipients (TOTR, 51+/-12 years) and 30 abdominal (kidney, kidney-pancreas, or liver) organ transplant recipients (AOTR, 46+/-11 years) from the 2006 Canadian Transplant Games, and 37 healthy controls (HC) completed a 6-MWT. VO2p, heart rate kinetics, and arterial compliance were determined., Results: The 6-MWT distance and highest VO2p were significantly lower in TOTR and AOTR versus HC. The highest 6-MWT heart rate was lower in TOTR (11%) and AOTR (13%) versus HC. VO2p kinetics were slower in TOTR (52+/-11 sec, P

We developed a multivariate prediction equation for estimating the highest obtainable pulmonary oxygen uptake (VO2p) during the 6-minute walk test (6-MWT) in 54 organ transplant recipients: heart/heart-double-lung (n=14), kidney/kidney-pancreas (n=16), liver (n=14), double lung (n=8), bone marrow (n=2). They were of age, 48+/-12 years. Participants performed a 6-MWT during which expired gases were collected and analyzed with a portable metabolic system interfaced with a wireless heart rate monitor. The following variables significantly contributed to the model for predicting the highest obtainable 6-MWT VO2p: 6-MWT distance (m), age (years), gender (male=0, female=1), resting heart rate, peak heart rate, weight (kg), and transplant type (kidney/kidney-pancreas=1, other=0), where: VO2p=1.253+0.022 (6-MWT distance)+0.112 (age) -3.192 (gender) -0.104 (resting heart rate)+0.127 (peak 6-MWT heart rate)-0.084 (weight)+2.116 (transplant type). The explanatory variables in our final model accounted for 78% of the variance in 6-MWT VO2p. In conclusion, the addition of an easily estimated 6-MWT VO2p will provide added clinical information of functional capacity following an exercise rehabilitation intervention or during routine follow-up for organ transplant recipients.

Objective: The purpose of this study was to compare an educational approach based on the Stages of Change Model with usual care education in reducing dietary fat intake and serum lipids in individuals with hyperlipidemia., Design: A 40-week randomized control study was conducted. Four education sessions were provided on an outpatient basis during a 1-month period with follow-up every 6 weeks., Participants: The sample consisted of 141 men and women with hyperlipidemia (mean age 50+/-11 years and a mean body mass index of 30+/-6) randomly assigned to one of two education interventions., Intervention: The stages of change group was provided with tailored dietary activities based on their readiness to change to reduce dietary fat intake. Dietary information and activities for the usual care program were developed for those individuals ready to make a change in their diets., Main Outcome Measures: Serum lipids, anthropometric measures, readiness to change, dietary intake, and exercise data were assessed at baseline, 4, 16, 28, and 40 weeks., Statistical Analyses: A repeated measures analysis of variance was used to compare differences between groups across time., Results: Total cholesterol, low-density lipoprotein cholesterol, and body weight decreased significantly at 4 weeks (P<0.05) for both groups and were sustained over time, with no differences between the groups., Conclusions: The stages of change education approach was not more effective than the usual care education approach in decreasing dietary fat intake and serum lipids in a classroom setting.

Objective: To elucidate the effects of atrioventricular (AV) dyssynchrony on phase I and phase II oxygen uptake (V(O2)) kinetics in chronotropically competent pacemaker patients during exercise of an intensity comparable to activities of daily living., Design: Blinded patients completed sub-ventilatory threshold (VT) work rate (WR) cycle ergometry exercise in random order during asynchronous AV pacing (AV OFF) and synchronous AV pacing., Setting: Tertiary care hospital in a major city., Subjects: Six chronotropically competent male pacemaker patients (mean [+/- SD] age, 68 +/- 10 years) with high-degree AV block and varying cardiac histories., Results: The phase I and phase II V(O2) amplitude response and gain (deltaV(O2)/WR ratio) were lower (p < 0.05) and the time course of phase II was slower (p < 0.05) during AV OFF; however, the O2 deficit was similar (p > 0.05) across pacing modes. The stroke volume index (SVI) was consistently lower (p < 0.05) during AV OFF pacing and was significantly correlated with the time course of phase II V(O2). A significant compensatory amplitude response in heart rate (HR) was observed in addition to a higher (p < 0.05) deltaHR/V(O2) ratio during AV OFF. Ventilatory responses were consistent with ventilatory-perfusion mismatching and perceived exertion was higher during asynchronous pacing., Conclusion: This study demonstrated that the contribution of SVI affects V(O2) kinetics and underscores the importance of the atrial contribution to ventricular filling and, consequently, to metabolic and hemodynamic responses. This study supports the theory of an O2 transport limitation and further implicates SV as a potential limiting factor during sub-VT exercise intensities that are comparable to those encountered in activities of daily living.

The benefits of cardiac rehabilitation (CR) have been linked to an individual's level of self-efficacy (SE) for the behaviours required. Successful behaviour performance is one way of increasing SE. The purpose of this study was to examine the reciprocal relationship of exercise SE to the specific outcomes of functional ability and health-related quality of life (HRQL) among a relatively healthy population in a CR program. One hundred and seventy new CR clients participated in this study. Those with high initial SE had greater functional ability and higher HRQL (p's < .01) than those with low initial SE through 12 weeks of CR. All outcomes, including SE, improved after 12 weeks of CR. Thus, the reciprocal nature of SE and CR exercise behaviours was demonstrated. We recommend further research to test the effectiveness of pre-screening new CR clients for SE, and using this information to guide the individual CR experience to optimize outcomes.

The present study examined the factors contributing to performance of a backward overhead medicine ball throw (B-MBT) across 2 types of athletes. Twenty male volleyball players (jump athletes) and 20 wrestlers (nonjump athletes) were evaluated on 4 measures of power, including B-MBT, chest medicine ball throw (C-MBT), countermovement vertical jump (CMJ), and power index (PI). The athletes also completed 3 measures of strength: a 1-repetition-maximum (1RM) bench press (BP), a 1RM leg press (LP), and combined BP + LP strength. Jump athletes demonstrated greater absolute scores for CMJ, C-MBT, and B-MBT (p < 0.05), whereas nonjump athletes demonstrated greater strength scores for BP and for BP + LP (p < 0.05). When performances were examined on a relative basis, jump athletes achieved superior scores for C-MBT (p < 0.05), whereas nonjump athletes had greater scores for BP, LP, and BP + LP (p < 0.05). For both groups, B-MBT had strong correlations with PI (r = 0.817 [jump] and 0.917 [nonjump]), whereas for C-MBT, only nonjump athletes demonstrated a strong correlation (r = 0.842). When expressed in relative terms, B-MBT was strongly correlated with C-MBT (r = 0.762 [jump] and 0.835 [nonjump]) and CMJ (r = 0.899 [jump] and 0.945 [nonjump]). Only nonjump athletes demonstrated strong correlations with strength for absolute LP (r = 0.801) and BP + LP (r = 0.810) strength. The interaction of upper- and lower-body strength and power in the performance of a B-MBT appears complex, with the contributing factors differing for athletes with divergent skill sets and performance demands.

Objective: To review the role of physical activity in primary prevention of cardiovascular (CV) diseases with particular attention to the intensity and amount of physical activity needed to benefit health., Quality of Evidence: MEDLINE was searched for articles published in the indexed English literature from January 1991 to December 2000 using key words related to physical activity (e.g., exercise, physical fitness), CV and coronary artery disease (CAD) risk factors (e.g., diabetes, hypertension, hyperlipidemia, obesity). Findings were supplemented by consensus documents and other published literature. Most articles described prospective observational studies., Main Message: Clear evidence indicates an inverse linear dose response between amount of physical activity and all-cause mortality, total CV disease, and CAD incidence and mortality. The minimal effective dose is unclear, but physical activity that results in energy expenditure of approximately 4200 kJ.week-1 appears to be associated with substantial benefits. Physical activity need not be vigorous to benefit health., Conclusion: Moderate activity, such as brisk walking for 30 to 60 minutes a day most days of the week, is associated with significant reductions in the incidence and mortality of CV disease.

The purpose of this study was to evaluate the validity and reliability of a medicine ball throw test to assess explosive power. Twenty competitive sand volleyball players (10 male players, 10 female players) performed a medicine ball throw and a standard countermovement vertical jump. The subjects attended 2 sessions; at each session, 3 attempts of each test were completed. The movement pattern for the medicine ball throw was a backward overhead toss. To standardize for body weight, a power index was calculated for the countermovement vertical jump using the Lewis formula. Validity was assessed using the best score for both the throw and the jump, and reliability was assessed using the best score from each session. There was a strong correlation between the distance of the medicine ball throw and the power index for the countermovement vertical jump (r = 0.906, p < 0.01). For the countermovement vertical jump, the test-retest reliability was 0.993 (p < 0.01), and for the medicine ball throw, the test-retest reliability was 0.996 (p < 0.01). These findings suggest that the medicine ball throw test is a valid and reliable test for assessing explosive power for an analogous total-body movement pattern and general athletic ability.

The effects of sensor selection and sensor blending on the cardiovascular response to graded exercise was evaluated in 10 patients (age 74 +/- 2 yrs; 7 men and 3 women) implanted with a dual sensor rate adaptive VVIR pacemaker (Vitatron Topaz model 515). Patients underwent three graded exercise tests (GXT) with sensor programming randomly assigned. For a given graded exercise text the pacemaker was programmed into activity sensing (ACT), QT sensing, or dual sensing (ACT = QT). Data were recorded at rest and during each stage of the graded exercise text. Oxygen uptake (VO2) was measured continuously using a Q Plex I system. Heart rate (HR), stroke volume (SV), and cardiac output (Qc) were measured by impedance cardiography. Systolic time intervals were calculated from simultaneous recordings of the ECG, phonocardiogram, and the impedance cardiogram. In response to the GXT no differences in peak VO2 were observed across the three sensor settings. Regardless of the sensor setting Qc increased linearly with each increment in VO2. The HR response to ACT only pacing was significantly higher than in the other two pacing conditions. During ACT only pacing SV failed to rise in response to exercise. The increased exercise Qc during QT and ACT = QT pacing were mediated by significant increases in both HR and SV. The QT and dual pacing conditions were also associated with longer diastolic filling times. The data indicate that the mechanisms responsible for the increase Qc during exercise were different for ACT versus ACT = QT or QT sensor-driven pacing.

The changes in stroke volume (SV) during upright exercise were studied in 20 insulin-dependent diabetics (IDDM) and 20 age- and sex-matched controls. None of the diabetics had any cardiovascular symptoms. In addition, tests of autonomic function were conducted in the diabetics, assessing changes in heart rate (HR) during deep breathing and the Valsalva maneuver. During exercise the SV in the controls gradually increased and then remained essentially unchanged until maximum HR was achieved. Seven of the diabetics failed to sustain an initial increase in SV (fall > 15%), eight showed a "delayed" increase in SV, and the remaining five demonstrated an increasing SV over the range from rest to peak exercise. Abnormal autonomic function results were found during deep breathing (four diabetics) and the Valsalva maneuver (four diabetics). Findings indicate that cardiac function could be abnormal in IDDM without evidence of autonomic dysfunction. This abnormality could be due to a specific cardiomyopathy.

The study was undertaken to examine the heart rate (HR) and stroke volume (SV) responses to upright exercise in patients after orthotopic cardiac transplantation (Group A). The findings were compared to data obtained from post-coronary artery bypass surgery patients (Group B) and from healthy subjects (Group C). All three groups (n = 12 in each group) were matched for age and gender. The preexercise HR and blood pressure were significantly higher in Group A (p < 0.05), whereas the SV was significantly lower (41 +/- 4mL.beat-1 vs 63 +/- 3 and 65 +/- 2 mL.beat-1 in Group B and C respectively, p < 0.05). In Group A, at submaximal work loads, the SV was consistently lower than in Groups B and C. During the early phases of exercise, the HR was consistently higher in Group A also. Systemic vascular resistance remained significantly higher in Group A throughout exercise (p < 0.05).

This study was undertaken to determine the blood pressure (BP) and cardiac output (Qc) responses to maximal isokinetic exercise. The subjects (n = 5) performed unilateral knee extension/flexion exercise (knee exercise) and unilateral elbow extension/flexion exercise (elbow exercise) at 0.52, 1.57, and 2.62 rads.sec-1. The BP was monitored using a cannula placed in the radial artery. Heart rate (HR), stroke volume (SV), and Qc were measured by impedance cardiography. In response to isokinetic exercise, HR and Qc increased significantly (p less than .01), while the SV did not. The BP response was characterized by significant increases in systolic, diastolic, and mean arterial pressure (MAP) (p less than .01). The Qc and MAP, responses were not influenced by the exercise velocity. The adjustments in HR, MAP, and rate pressure product (RPP) to the elbow exercise were qualitatively similar to those seen during the knee exercise, but the absolute values achieved were smaller (p less than .05). Compared with maximal dynamic exercise, the HR and SV responses to the knee exercises were lower. The MAP response to isokinetic exercise equaled the highest value achieved during dynamic exercise. Findings from the present study suggest that the cardiovascular stress (the increase in HR, MAP, and RPP) associated with isokinetic exercise is independent of the velocity of movement and is proportional to the active muscle mass.

The effect of hydraulic circuit training (HCT) on stroke volume (SV), cardiac output (Qc), aerobic power (peak VO2), and muscular strength and endurance was evaluated in 24 post-coronary artery bypass (CABS) patients (mean age = 52.8 +/- 2.6 yr). All assessments other than muscular strength and endurance were based upon a symptom limited graded exercise test on a bicycle ergometer. Muscular strength and endurance were assessed on a Cybex II isokinetic dynamometer. Sixteen patients were assigned randomly to 8 wk of cycle training or HCT (N = 8 in each). Subjects assigned to cycle training exercised on bicycle ergometers. The HCT group exercised on a three-station circuit, completing three circuits per day. Each circuit consisted of three 20 s work intervals at each station with a 1:1 work:rest ratio. Results from the training groups were compared with results from eight patients who served as a nonexercising control group. Following training the peak VO2 was significantly increased in the training groups (20% and 11% for the cycle and HCT groups, respectively; P less than 0.05). For both training groups, the increase in peak VO2 was associated with increases in SV and Qc and a reduction in heart rate (HR) at submaximal levels of exercise (P less than 0.05). Only the HCT group demonstrated an increase in both muscular strength and endurance during knee and shoulder exercises (P less than 0.05). These findings suggest that a program of HCT can elicit improvements in cardiovascular fitness and muscular strength and endurance in post-CABS patients.

The need to adjust atrioventricular delay relative to pacing rate in atrial synchronous pacemakers was assessed in eight subjects treated for complete heart block (mean age 61 +/- 3.4 years). First, an inverse relationship between heart rate and PR interval was confirmed in two groups of healthy subjects and one group of patients recovering from myocardial infarction. Due to the limitations of the available pacemakers this relationship could not be precisely reproduced. Subjects with pacemakers performed an initial exercise test on a bicycle ergometer to determine heart rate response; this information was used in part 2 to program atrioventricular delay relative to heart rate. During a second exercise test, a rate-adapting atrioventricular delay was compared to a constant atrioventricular delay of 200 ms at matched heart rates. Cardiac output was measured noninvasively by impedance cardiography. The results of part 1 showed an abnormal pattern in the response of stroke volume to exercise in seven subjects. Part 2 results demonstrated no significant difference (P greater than 0.05) between a rate-adapting atrioventricular delay and a constant delay of 200 ms for heart rate, stroke volume, cardiac output, blood pressure or Borg scale. A trend towards increased stroke volume with a rate-adapting atrioventricular delay was observed. Stroke volume was 13% larger with a rate-adapting atrioventricular delay of 125 ms at a heart rate of 125 beats/min. These results suggest that subjects with atrial synchronous pacemakers have a variable stroke volume response to exercise. It appears that in these subjects the ability to increase heart rate is the key factor for raising cardiac output during exercise.

Between January 1982 and June 1989, 102 consecutive patients (25 women and 77 men) who had isolated aortic valve replacements were reviewed. The overall early operative mortality was 5%. The deaths were related mainly to pump failure and endocarditis. The early operative mortality in younger patients (less than 70 years old) was 3.5% and in the elderly (70 or older) 11%. The overall late mortality was 4%. All of the survivors except three (follow-up by telephone) were seen in follow-up by cardiologists. The mean follow-up was 40 +/- 26 months (range four to 89). Eighty-seven per cent of all patients or 92% of the survivors in the younger population did well following the operation. In the elderly patients, the results were less favorable (P less than 0.025). The overall cumulative survival was 92% at one year and 89% at five years. The actuarial event-free percentage of survivors was 86% at one year and 74% at five years. Aortic valve replacement can be accomplished in symptomatic patients with an acceptable operative mortality. Long term follow-up of these patients showed functional improvement and low mortality.

The left ventricular response to upright bicycle exercise was studied in 39 unselected, non-beta blocked patients (mean(SEM) age 54.2(1.7)yr) (mean(SEM) resting ejection fraction 41.9(2.3)%) 8-10 weeks after myocardial infarction. Nine healthy, age matched, sedentary adult men were studied for comparison (mean(SEM) age 49.8(0.9)yr). The stroke volume and cardiac output were measured by impedance cardiography at rest and after each 3 min workload until symptom limited maximum. The patients were separated into three groups based on stroke volume response to graded exercise. Group 1 (n = 14) had a normal stroke volume response to increasing heart rate. In group 2 (n = 13) stroke volume increased initially then decreased by greater than 15% at a heart rate greater than 100-105 beats.min-1. In group 3 (n = 12) stroke volume failed to increase during exercise. In group 1 cardiac output and mean arterial pressure increased whereas vascular resistance decreased during exercise in a normal fashion. Group 2 had an increased mean arterial pressure and systemic vascular resistance throughout exercise while heart rate increased in a similar fashion to group 1 until work of greater than 70 W was undertaken, at which time heart rate increased in a curvilinear fashion and cardiac output was attenuated. Group 3 had an attenuated cardiac output and a higher heart rate during exercise. In this group of patients systemic vascular resistance failed to decrease normally during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Inversion devices have been advocated as means of therapy for patients with low back pain. The present investigation was undertaken to determine the cardiovascular responses to vertical head-down suspension with such a device. Eight men were monitored for three minutes in the upright and supine position, and for ten minutes in the vertical head-down position. Stroke volume (SV), heart rate (HR), cardiac output (QT), segmental arm blood flow (ABF), and segmental leg blood flow (LBF) were measured by impedance plethysmography. Moving from the upright to the supine positions resulted in an SV increase from 93.1 +/- 18.8 to 138.2 +/- 28.2 ml.beat-1 (p less than 0.01). During the first minute of suspension a further increase in SV to a maximum of 178.6 +/- 45.0 ml.beat-1 was noted. By the end of the suspension period, SV had declined to 159.6 +/- 34.2 ml.beat-1. Resumption of the upright position was associated with a reduction in SV to 94.3 +/- 15.8 ml.beat-1. Changes in QT across the supine and vertical head-down positions reflected the changes in SV. The vertical head-down position was also associated with a gradual reduction in both ABF and LBF. These data suggest that the primary effect of inverted suspension was a transient increase in venous return, which requires an effective ventricular response. An element of caution should be exercised in using these devices to avoid aggravating concurrent pathologic conditions.

In order to investigate the influence of high-velocity circuit resistance training on maximal aerobic power, maximal stroke volume and cardiac output, and blood lactate removal during recovery, 16 habitually active males were blocked on initial VO2max into either training or control groups. The training group completed two (weeks 1 and 2) or three (weeks 3-6) circuits of 10 variable-resistance hydraulic exercise stations at an exercise: relief ratio of 1:2 on alternate days over six weeks. Angular velocities of movement were maintained at approximately 3.1 rad.s-1. Following training, the VO2max was increased (p less than .01) from 4.32 to 4.68 1.min-1. Maximal stroke volume was increased (p less than .05) from 120 to 129 mL and heart rate response to an absolute submaximal exercise load was decreased (p less than .05) from 153 to 146 beats.min-1. As well, enhanced (p less than .01) removal of lactate from the blood was observed during recovery from exhausting exercise. No changes were observed for control subjects. These results indicate that positive alterations in aerobic and cardiovascular function may be achieved consequent to high-velocity circuit resistance training.

The overall accuracy of cardiac output measurements made by impedance cardiography during maximum exercise was studied in man. Initially, the systematic error of the technique was assessed over the range 3.5 to 18 litre . min-1 by comparing with simultaneous measurements of cardiac output made using the direct Fick method. No systemic error was demonstrated in 40 estimations made in 20 subjects. The random error was assessed in 4 subjects in a steady state at rest and during exercise at 80 and 130 W and found to be less than 5% in each subject. The reproducibility of maximum exercise response was assessed in six healthy male subjects (age 26.2 +/- 4.4 years, +/- SEM) who underwent maximum exercise tests twice, 1 week apart, on a bicycle ergometer. Simultaneous recordings of cardiac output and oxygen uptake (VO2) at rest and during each 3 min stage of exercise were made. Highly significant correlations were obtained in the stroke volume (r = 0.84, p less than 0.001), cardiac output (r = 0.98, p less than 0.001) and VO2 (r = 0.98, p less than 0.001) between the two tests. Average maximum cardiac output was 27.0 +/- 1.2 litre . min-1 (+/- SEM) and maximum VO2 was 4.4 +/- 0.2 litre . min-1 (+/- SEM). These results show that measurements of cardiac output were reproducible over one week. Impedance cardiography is non-invasive technique which is as accurate as invasive methods and can be used for maximal exercise testing.