Acute effects of exercise on cognition in patients with chronic obstructive pulmonary disease

Prior data indicate positive effects of long-term exercise interventions for cognitive functioning among patients with chronic obstructive pulmonary disease (COPD), but no prior studies have examined acute effects of individual bouts of exercise among patients with COPD. This study evaluated acute effects of exercise on cognitive performance in a community-based sample of patients with COPD and a healthy control group, matched by age, sex, and education. Twenty-nine older adults with COPD (mean age = 67.8 yr [+/- 7.4]; range: 56-85; 17 women) and 29 matched healthy control subjects (mean age = 68.7 yr [+/- 6.0] ) were recruited from the community. All participants completed a 20-min exercise session in which they exercised to a peak level and a video control condition in which they were provided information about exercise and cholesterol. Conditions were separated by a 1-wk interval, and order of participation in conditions was randomly assigned. Assessments of cognitive performance (Trail Making Test, Digit Symbol, Verbal Fluency, Digit Span, Finger Tapping) were administered before and after each condition (exercise and video). Among patients with COPD, acute exercise was associated with improved performance on the Verbal Fluency test, a measure of verbal processing, suggesting that acute exercise may benefit aspects of cognitive performance among patients with COPD.

Depression as an antecedent to heart disease among women and men in the NHANES I study. National Health and Nutrition Examination Survey

BACKGROUND

Depression predicts morbidity and mortality among individuals who have coronary heart disease (CHD), and there is increasing evidence that depression may also act as an antecedent to CHD. The studies that have reported a relationship between depression and CHD incidence or mortality either were restricted to men only or analyzed women and men together. The present investigation was conducted to evaluate the differential effect depression may have on CHD incidence and mortality in women and men.

RESEARCH METHODS

We analyzed data from 5007 women and 2886 men enrolled in the first National Health and Nutrition Examination Survey (NHANES I) who were free of CHD at the 1982-1984 interview and who had completed the Center for Epidemiologic Studies Depression Scale (CES-D). Participants were evaluated from the 1982 interview date either until the end of the study (1992 interview date) or until the occurrence of a CHD event. Using CHD incidence and CHD mortality (International Classification of Disease, Ninth Revision, codes 410-414) as the outcome variables, Cox proportional hazards regression models were developed to evaluate the relative risk (RR) of CHD incidence and mortality in the depressed women and men separately, controlling for standard CHD risk factors.

RESULTS

The women experienced 187 nonfatal and 137 fatal events, compared with 187 nonfatal and 129 fatal events among the men. The adjusted RR of CHD incidence among depressed women was 1.73 (95% confidence internal [CI], 1.11-2.68) compared with nondepressed women. Depression had no effect on CHD mortality in the women (RR, 0.74; 95% CI, 0.40-1.48). The adjusted RR of CHD incidence among depressed men was 1.71 (95% CI, 1.14-2.56) compared with nondepressed men. Depressed men also had an increased risk of CHD mortality compared with their nondepressed counterparts, with an adjusted RR of 2.34 (95% CI, 1.54-3.56).

CONCLUSIONS

In this sample, while controlling for possible confounding factors, depression was associated with an increased risk of CHD incidence in both men and women, as well as CHD mortality in men. Depression had no effect on CHD mortality in women.

Continuous handrail support, oxygen uptake, and heart rate in women during submaximal step treadmill exercise

Past research suggests that continuous handrail support during exercise attenuates physiologic responses to exercise and reduces aerobic benefits; however, this phenomenon has not been systematically studied in women exercising on the step treadmill. The effects of three levels of handrail support (continuous light, continuous very light, or no handrail support) on oxygen uptake and heart rate during step treadmill exercise were examined in 15 healthy women. Measures were obtained during 6 bouts of exercise, 3 bouts at 25 steps/min followed by 3 bouts at 33 steps/min. At both step rates, mean oxygen uptake was significantly reduced during continuous light and continuous very light handrail support as compared with no handrail support, and mean heart rate was significantly reduced during continuous light versus no handrail support. At 25 steps/min only, mean heart rate was significantly reduced during continuous very light versus no handrail support. Findings indicate that women who use even continuous light or continuous very light handrail support attenuate physiologic responses during step treadmill exercise, thereby reducing aerobic requirements and gaining suboptimal benefits from exercise.

Effect of amlodipine on mode of death among patients with advanced heart failure in the PRAISE trial. Prospective Randomized Amlodipine Survival Evaluation

Investigations of calcium antagonists in patients with advanced heart failure have raised concern over an increased risk of worsening heart failure and heart failure deaths. We assessed the effect of amlodipine on cause-specific mortality in such patients enrolled in a randomized, double-blind, placebo-controlled trial. In total, 1,153 patients in New York Heart Association class IIIb or IV heart failure were randomized to receive amlodipine or placebo, along with angiotensin-converting enzyme inhibitors, diuretics, and digitalis. Over a median 14.5 months of follow-up, 413 patients died. Cardiovascular deaths accounted for 89% of fatalities, 50% of which were sudden deaths and 45% of which were due to pump failure, with fewer attributed to myocardial infarction (3.3%) or other cardiovascular causes (1.6%). Amlodipine treatment resulted in a greater relative reduction in sudden deaths (21%) than in pump failure deaths (6.6%) overall. When patients were classified by etiology of heart failure (ischemic or nonischemic), cause-specific mortality did not differ significantly between treatment groups in the ischemic stratum. In the nonischemic stratum, however, sudden deaths and pump failure deaths were reduced by 38% and 45%, respectively, with amlodipine. Thus, when added to digitalis, diuretics, and angiotensin-converting enzyme inhibitors in patients with advanced heart failure, amlodipine appears to have no effect on cause-specific mortality in ischemic cardiomyopathy, but both pump failure and sudden deaths appear to be decreased in nonischemic heart failure patients treated with amlodipine.

Stepping as an exercise modality for improving fitness and function

This article describes three stepping modes, summarizes research on stepping in healthy adults and patients with peripheral vascular disease, and discusses clinical implications and directions for future research. Stepping exercise has been shown to increase cardiorespiratory fitness in healthy adults and increase physical function in patients with peripheral vascular disease. Although further research is warranted, stepping exercise has potential value as a nursing intervention to correct alterations in physical mobility in selected populations. Stepping is proposed as an alternative exercise strategy; one which adds variety to exercise routines and may enhance long-term exercise adherence.

Evaluation of a commercial accelerometer (Tritrac-R3 D) to measure energy expenditure during ambulation

This study evaluated the ability of a commercially available accelerometer (Tritrac-R3 D) to measure energy expenditure in 16 subjects at rest (pre- and post-exercise) and during three different intensities of steady-state exercise (40-70% of peak oxygen consumption [VO2peak]) while ambulating on a treadmill (no grade). Oxygen consumption and the respiratory exchange ratio from indirect calorimetry and the vector magnitude of triaxial accelerations were used to estimate energy expenditure using the manufacturers' equations. There was a significant relationship between indirect calorimetry-derived energy expenditure and the energy expenditure derived from the accelerometer (r=0.96). Using analysis of variance, there was no difference in the energy expenditure derived by the two methods at rest before exercise and during the three different intensities of ambulatory exercise. There was a significant difference between energy expenditure derived via indirect calorimetry and with the accelerometer during rest after exercise, probably due to the failure of the accelerometer to accurately estimate the energy expenditure associated with the progressive decline in post-exercise oxygen consumption. Thus, this commercially available accelerometer appears to provide statistically acceptable estimates of energy expenditure at rest and during zero-grade treadmill ambulation up to about 70% VO2peak. This may indicate its acceptable utility for large-scale population studies of physical activity involving this mode of movement. The failure of the accelerometer to accurately estimate energy expenditure during recovery from exercise may contribute to an underestimation of energy expenditure in some physically active individuals.

Stress management and exercise training in cardiac patients with myocardial ischemia. Effects on prognosis and evaluation of mechanisms

BACKGROUND

Previous studies have demonstrated that myocardial ischemia can be elicited by mental stress in the laboratory and during daily life and that ischemia induced by mental stress is associated with an increased risk for future cardiac events in patients with coronary artery disease.

OBJECTIVES

To examine the extent to which ischemia induced by mental stress can be modified by exercise stress management, and to evaluate the impact of these interventions on clinical outcomes.

METHODS

One hundred seven patients with coronary artery disease and ischemia documented during mental stress testing or ambulatory electrocardiographic monitoring were randomly assigned to a 4-month program of exercise or stress management training. Patients living at a distance from the facility formed a nonrandom, usual care comparison group. Myocardial ischemia was reassessed following treatment, and patients were contacted annually for as long as 5 years to document cardiac events, including death, nonfatal myocardial infarction, and cardiac revascularization procedures.

RESULTS

Twenty-two patients (21%) experienced at least 1 cardiac event during a mean (+/- SD) follow-up period of 38 +/- 17 months. Stress management was associated with a relative risk of 0.26 compared with controls. The relative risk for the exercise group also was lower than that of controls, but the effect did not reach statistical significance. Stress management also was associated with reduced ischemia induced by mental stress and ambulatory ischemia.

CONCLUSION

These data suggest that behavioral interventions offer additional benefit over and above usual medical care in cardiac patients with evidence of myocardial ischemia.

Effects of mental stress on myocardial ischemia during daily life

OBJECTIVE

To determine the relative risk of myocardial ischemia triggered by specific emotions during daily life.

DESIGN AND SETTING

Relative risk was calculated by the recently developed case-crossover method, in which the frequency of a presumed trigger during nonischemic, or control, hours is compared with the trigger's frequency during ischemic, or case, hours. Outpatients at Duke University Medical Center, Durham, NC, underwent 48 hours of ambulatory electrocardiographic (ECG) monitoring with concurrent self-report measures of activities and emotions. Occurrences of negative emotions in the hour before the onset of myocardial ischemia were compared with their usual frequency based on all hours in which ischemia did not occur.

SUBJECTS

From a sample of 132 patients with coronary artery disease and recent evidence of exercise-induced ischemia who underwent 48 hours of ambulatory ECG monitoring, 58 patients exhibited ambulatory ischemia and were included in the analysis.

OUTCOME MEASURES

Myocardial ischemia during 48-hour ECG monitoring was defined as horizontal or downsloping ST-segment depression of 1 mm (0.1 mV) or more for 1 minute or longer compared with resting baseline. The ECG data were cross-tabulated with subjects' concurrent diary ratings of 3 negative emotions-tension, sadness, and frustration-and 2 positive emotions-happiness and feeling in contro-on a 5-point scale of intensity.

RESULTS

The unadjusted relative risk of occurrence of myocardial ischemia in the hour following high levels of negative emotions was 3.0 (95% confidence interval [CI], 1.5-5.9; P<.01) for tension, 2.9 (95% CI, 1.0-8.0; P<.05) for sadness, and 2.6 (95% CI, 1.3-5.1; P<.01) for frustration. The corresponding risk ratios adjusted for physical activity and time of day were 2.2 (95% CI, 1.1 -4.5; P<.05) for tension, 2.2 (95% CI, 0.7-6.4; P=.16) for sadness, and 2.2 (95% CI, 1.1-4.3; P<.05) for frustration.

CONCLUSIONS

Mental stress during daily life, including reported feelings of tension, frustration, and sadness, can more than double the risk of myocardial ischemia in the subsequent hour. The clinical significance of mental stress-induced ischemia during daily life needs to be further evaluated.

Step treadmill exercise training and blood pressure reduction in women with mild hypertension

Stepping as an exercise modality has gained increasing popularity. The step treadmill is an exercise machine which simulates actual stair-climbing. The purpose of this study was to determine the effectiveness of a 16-week supervised aerobic step treadmill exercise training protocol in reducing resting blood pressure in women with unmedicated mild hypertension. During the training protocol, subjects exercised during a self-selected appointment three times a week on the step treadmill, increasing from 20 minutes up to 60 minutes per session, at a target heart rate corresponding to 70-80% heart rate reserve for 16 weeks. Utilizing paired t-test analysis, mean resting systolic blood pressure decreased from 142.2 +/- 9.1 to 132.7 +/- 8.2 mm Hg (p < .01) and mean resting diastolic blood pressure decreased from 93 +/- 4.9 to 87.4 +/- 5.4 mm Hg (p < .01) during the 16-week protocol. Mean maximal oxygen uptake was significantly increased, whereas mean body weight did not change significantly over the 16-week period. Large scale trials are needed to further delineate the effectiveness of stepping as a health care intervention in adults with unmedicated mild hypertension, especially in women.

Mental stress--induced myocardial ischemia and cardiac events

OBJECTIVE

To assess the clinical significance of mental stress-induced myocardial ischemia in patients with coronary artery disease (CAD).

DESIGN AND SETTING

Cohort study in outpatients in a tertiary care teaching hospital assessed at baseline and followed up for up to 5 years.

SUBJECTS

A total of 126 volunteer patients (112 men, 14 women; mean age, 59 years) with documented CAD and exercise-induced myocardial ischemia.

OUTCOME MEASURES

Patients underwent baseline mental stress and exercise testing using radionuclide ventriculography and 48-hour Holter monitoring. Patients were subsequently contacted by mailed questionnaires or telephone to document cardiac events, including death, nonfatal myocardial infarction, and cardiac revascularization procedures. Logistic regression and Cox proportional hazards models were used to examine the prognostic value of the ischemic measures after adjusting for such potential confounding factors as age, baseline left ventricular ejection fraction (LVEF), and history of myocardial infarction.

RESULTS

Twenty-eight patients (22%) experienced at least 1 cardiac event. Baseline mental stress-induced ischemia was associated with significantly higher rates of subsequent cardiac events (odds ratio, 2.8; 95% confidence interval [CI], 1.0-7.7; P < .05). The LVEF change during mental stress was significantly related to event-free survival (risk ratio [RR], 2.4; 95% CI, 1.12-5.14; P = .02), controlling for age, history of prior myocardial infarction, and baseline LVEF. This relationship remained significant after controlling for electrocardiogram (ECG)-defined ischemia during exercise (RR, 2.2; 95% CI, 1.01-4.81; P < .05). The RR for ECG-defined ischemia during exercise testing was 1.9 (95% CI, 0.95-3.96; P = .07) and the RR for ambulatory ECG ischemia was 0.75 (95% CI, 0.35-1.64; P = .47).

CONCLUSIONS

The presence of mental stress-induced ischemia is associated with significantly higher rates of subsequent fatal and nonfatal cardiac events, independent of age, baseline LVEF, and previous myocardial infarction, and predicted events over and above exercise-induced ischemia. These data suggest that the relationship between psychological stress and adverse cardiac events may be mediated by the occurrence of myocardial ischemia.

Association of physical fitness and transient myocardial ischemia in patients with coronary artery disease

PURPOSE

To examine the relationship between physical fitness and transient myocardial ischemia (TMI) in the laboratory and during daily life, in a sample of coronary patients with a recent positive exercise test.

METHODS

47 patients with coronary disease (CAD) participated in laboratory mental and exercise stress testing and 48-hour outpatient Holter monitoring after being withdrawn from ant-ischemic medications. During laboratory testing, left ventricular performance was assessed by radionuclide ventriculography. Physical fitness was assessed by measurement of oxygen consumption during symptom-limited exercise treadmill testing.

RESULTS

Higher physical fitness subjects were less likely to exhibit wall-motion abnormalities in response to mental stress (P < .05), and to exercise stress (P < .05) testing. They also had smaller decreases in left ventricular ejection fraction (LVEF) in response to mental stress than less fit subjects (P .056), and exhibited a mean increase in LVEF during exercise, compared to the less fit subjects who exhibited a decrease in LVEF (P < .02). Moreover, higher fit subjects exhibited fewer episodes of TMI (P < .04), for a shorter duration (P < .04), and less total ischemic burden (P < .04) during Holter monitoring.

CONCLUSION

These findings suggest that within a population of CAD patients, higher levels of physical fitness are associated with less TMI assessed in the laboratory and during routine activities of daily living.

Mental stress-induced ischemia in the laboratory and ambulatory ischemia during daily life. Association and hemodynamic features

BACKGROUND

The purpose of this study was to determine the correspondence of mental stress-induced ischemia in the laboratory with ambulatory ischemia and to assess the relationship between hemodynamic responses to mental stress and the occurrence of ischemia. Although exercise testing is usually used to elicit myocardial ischemia, ischemia during daily life usually occurs at relatively low heart rates and in the absence of strenuous physical exercise. Mental stress has been shown to trigger ischemic events in the laboratory at lower heart rates but at blood pressures comparable to exercise. We therefore compared the extent to which mental stress and exercise testing identify patients who develop ischemia out of hospital.

METHODS AND RESULTS

One hundred thirty-two patients with documented coronary disease and recent evidence of exercise-induced myocardial ischemia underwent 48-hour ambulatory monitoring and radionuclide ventriculography during exercise and mental stress testing. Patients who displayed mental stress-induced ischemia in the laboratory were more likely to exhibit ischemia during daily life (P < .021). Furthermore, patients who exhibited ischemia during ambulatory monitoring displayed larger diastolic blood pressure (P < .006), heart rate (P < .039), and rate-pressure product responses (P < .018) during mental stress.

CONCLUSIONS

Among patients with prior positive exercise stress tests, mental stress-induced ischemia, defined by new wall motion abnormalities, predicts daily ischemia independent of exercise-induced ischemia. Exaggerated hemodynamic responses during mental stress testing also identify individuals who are more likely to exhibit myocardial ischemia during daily life and mental stress.

Predicting the risk of abrupt vessel closure after angioplasty in an individual patient

OBJECTIVES

We proposed to examine the relation between angiographic morphologic characteristics and abrupt closure after coronary angioplasty and to develop an empirically based risk stratification system.

BACKGROUND

Certain lesion morphologic characteristics are associated with higher rates of abrupt closure after coronary angioplasty. Previous approaches have been limited by relatively small sample sizes and an inability to combine multiple characteristics to predict risk in an individual patient.

METHODS

Lesion morphology was determined for 779 lesions in 658 patients undergoing an elective first angioplasty. Abrupt closure occurred in 63 lesions (8.1%). Variables associated with abrupt closure were identified by univariate and stepwise multiple logistic regression analysis, and internal validity was assessed by use of bootstrapping. An empirically based scoring system was developed by assigning different weights to each predictive characteristic and was then validated.

RESULTS

Almost all lesion characteristics previously labeled "adverse" were associated with an increased risk of abrupt closure, but only total occlusion, location at a branch point, increasing lesion length, evidence for thrombus and right coronary artery location were statistically significant independent predictors. Despite the large sample size, the study was underpowered to detect even a 50% increase in risk with many characteristics. Using a scoring system, we assigned each lesion a specific risk of abrupt closure. The distribution of risk was broad, with 20% of patients having < or = 2.5% risk and 25% having > 10% risk. Internal validation techniques revealed that when 10% of patients were randomly eliminated from the sample in multiple iterations, the risk estimates varied, again pointing to the need for a larger sample.

CONCLUSIONS

Empirically based weighting of lesion characteristics could quantify the risk of abrupt closure for individual patients, but a very large sample will be required to understand the interplay of complex lesion characteristics in altering expected outcomes.

Relation of cardiovascular responses to mental stress and cardiac vagal activity in coronary artery disease

Forty-six patients with documented coronary artery disease were studied to examine the relation of cardiovascular reactivity to mental stress and cardiac vagal activity. Cardiac vagal activity was measured by means of frequency-domain analysis of heart rate variability with 48-hour out-of-hospital Holter monitoring. The amplitude of the high-frequency component (0.16 to 0.40 Hz) of heart rate variability is considered to be an index of cardiac vagal activity. Cardiovascular reactivity was measured in the laboratory during a 3-minute public speaking task. Results revealed that (1) the amplitude of the high-frequency component was significantly higher during sleep (24.6 +/- 11.3 ms) than during waking (18.2 +/- 8.0 ms) (p = 0.002); (2) compared to subjects with low diastolic blood pressure reactivity, those who displayed high diastolic blood pressure reactivity exhibited a significantly lower amplitude of the high-frequency component (19.2 +/- 6.9 vs 23.4 +/- 9.6 ms, p = 0.03). These results indicate that decreased cardiac vagal activity may contribute to the exaggerated diastolic blood pressure reactivity to mental stress in patients with coronary artery disease.

Long-term outcome following successful reopening of abrupt closure after coronary angioplasty

Abrupt closure after coronary angioplasty is often successfully treated by repeat dilation. Long-term follow-up, including 6-month repeat catheterization and 12-month clinical evaluation, was obtained in 1,056 patients treated with acute (n = 335) or elective (n = 721) coronary angioplasty to evaluate the long-term impact of successful reopening of abrupt closure. Abrupt closure occurred in 13.5% of patients and was successfully reopened in 58%. Adverse outcomes including restenosis, death, bypass surgery, myocardial infarction and repeat angioplasty were compared between patients with successfully treated abrupt closure and those with successful procedures (residual diameter stenosis < or = 50%) without abrupt closure. For patients with acute angioplasty, the restenosis rates (> 50% diameter stenosis at follow-up) were 64% for those with successfully treated abrupt closure versus 36% for those with successful procedures without abrupt closure (p < 0.01). In addition, subsequent myocardial infarction (12 vs 3%; p = 0.01) and repeat angioplasty (21 vs 10%; p = 0.03) were more frequent in the group with abrupt closure. For patients with elective angioplasty, restenosis was 43% in those with successfully treated abrupt closure versus 45% in those without abrupt closure (p = NS). Subsequent death and myocardial infarction were more frequent in patients with abrupt closure (death: 12 vs 3% [p < 0.01]; myocardial infarction: 13 vs 3% [p < 0.01]). Long-term adverse events are increased in patients with successfully treated abrupt closure compared to those with successful procedures without abrupt closure.

Restenosis after coronary angioplasty: an overview

Despite substantial basic and clinical efforts to address the problem of restenosis after percutaneous coronary intervention, effective preventive therapies have not yet been developed. Nevertheless, the accumulated information has provided much insight into the process of restenosis in addition to allowing standards to be developed for adequate clinical trials. The pathophysiology of restenosis increasingly appears to be distinct from that of primary atherosclerosis. Restenosis involves elastic recoil, incorporation of thrombus into the lesion and fibrocellular proliferation in varying degrees in different patients. Lack of an animal model that satisfactorily mimics restenosis is a major impediment to further understanding of the process. Clinical studies are hampered by difficulties in finding a single unifying definition of restenosis and by variable methods of reporting follow-up. Reporting of clinical outcomes of all patients in angiographic substudies would allow a more satisfactory interpretation of the results of clinical trials. Current noninvasive test results are not accurate enough to substitute for angiographic and clinical outcome data in intervention trials. In the majority of observational studies, only diabetes and unstable angina have emerged as consistently associated with restenosis; whereas most of the standard risk factors for atherosclerosis have a less consistent relation. Disappointingly, the new atherectomy and laser technologies have not affected restenosis rates. The one possible exception is coronary stenting, as a result of the larger luminal diameter achieved by the placement of the stent. In conclusion, although substantial continued effort is necessary to explore the basic aspects of cellular proliferation and mechanical alteration of atherosclerotic vessels, attention to the principles of clinical trials and observation are required to detect the impact of risk factors and interventions on the multifactorial problem of restenosis. Adequate sample sizes, collection of clinical and angiographic outcomes and factorial study designs hold promise for unraveling this important limitation of percutaneous intervention.