Increased central adiposity in morbidly obese patients with obstructive sleep apnoea.

BACKGROUND: With the growing epidemic of obesity, few data are available regarding adipose distribution and the severity of sleep apnoea. Our aim was to measure precisely adipose distribution with dual-energy X-ray absorptiometry (DXA) in a morbidly obese population with and without obstructive sleep apnoea (OSA). METHODS: Morbidly obese female subjects without a history of OSA underwent overnight polysomnography and DXA analysis. Subject demographics, DXA variables, serum laboratory markers and physical exam characteristics were compared between individuals with and without OSA. RESULTS: For the study population (n= 26), mean body mass index (BMI) was 45.9 ± 7.8 kg/m(2); mean age was 47.5 ± 10.2 years and all were female. The central adiposity ratio (CAR) was higher in individuals with OSA (apnoea-hypopnoea index > 5) than those without OSA (1.1 ± 0.05 vs 1.0 ± 0.04; P = 0.004). No difference was observed in Epworth Sleepiness Scale scores, body mass index (BMI) or neck circumference between groups. CONCLUSIONS: OSA is associated with increased central adipose deposition in patients with a BMI of >40 kg/m(2). These data may be helpful in designing future studies regarding the pathophysiology of OSA, and potential treatment options.

Hydralazine therapy in severe chronic heart failure: inability of radionuclide left ventricular ejection fraction measurement to predict the hemodynamic response.

Simultaneous hemodynamic and radionuclide angiographic assessment was made at rest and during exercise in nine patients with severe chronic congestive heart failure to determine the value of radionuclide left ventricular ejection fraction measurement in predicting the hemodynamic response to short-term treatment with oral hydralazine. Hydralazine, 50 to 100 mg orally every 6 hours, produced significant increases in cardiac index and stroke volume index at rest and during exercise (p less than 0.01) and in left ventricular stroke work index at rest (p less than 0.01) and during exercise (p less than 0.05), significant decreases in systemic vascular resistance at rest and during exercise (p less than 0.01) and significant increases in radionuclide angiographic left ventricular ejection fraction at rest (control 0.21 +/- 0.06 vs. hydralazine 0.26 +/- 0.07, p less than 0.01) and during exercise (control 0.21 +/- 0.08 vs. hydralazine 0.24 +/- 0.09, p less than 0.05). However, there were no statistically significant correlations between changes in radionuclide ejection fraction with hydralazine and changes in hemodynamic variables with hydralazine, either at rest or during exercise. Patients responding hemodynamically to hydralazine could not be separated from those not responding on the basis of the radionuclide ejection fraction at rest or changes in ejection fraction with hydralazine.(ABSTRACT TRUNCATED AT 250 WORDS)

Theophylline disposition in obesity.

Theophylline disposition was examined in 14 obese subjects and 57 normal subjects. A single oral dose of aminophylline solution was given and serum and saliva samples were collected over several hours and assayed by high-pressure liquid chromatography. The apparent volume of distribution (Vd) and body clearance (ClB) were analyzed for total body weight (TBW) and ideal body weight (IBW). The Vd averaged 0.482 (SD = 0.084) L/kg TBW in normals vs 0.382 (0.069) L/kg TBW and 0.77 (0.189) L/kg IBW in obese subjects. The ClB averaged 63.0 (28.5) ml/hr/kg IBW in normals compared to 32.8 (11.1) ml/hr/kg TBW and 64.1 (20.8) ml/hr/kg IBW in obese subjects. Similar Vd values between the two groups when TBW is used indicates that loading dose is best calculated based on TBW. Similar ClB based on IBW in normal and obese subjects indicates that IBW should be used to calculate maintenance doses for theophylline. Mean half-lives were longer in obese subjects than in normals, 8.6 (2.0) and 6.0 (2.1) hr, respectively, suggesting that obese patients may need less frequent dosing.

Validity of skinfold thickness measures of formerly obese adults.

UNLABELLED: To assess the validity of skinfold thickness estimates of body fatness in formerly morbid obese adults, 23 patients (17 women, 6 men) who had completed a protein-sparing modified fast were studied. Mean +/- SD weight loss was 60.7 +/- 20.6 kg for men and 42.6 +/- 11.5 kg for women. Body density and percent body fatness were determined after weight loss according to four commonly used skinfold equations: Pollock (P); Durnin-Rahaman (D-R); Durnin-Womersley (D-W); and, Jackson-Pollock (J-P). The validity of these measurements was assessed by hydrostatic weighing, which revealed a percent body fatness of 20.4 +/- 6.5 for men and 29.8 +/- 8.4 for women. The mean difference and total error (square root of the mean of squared deviations) between skinfold predicted and hydrostatically-determined percent body fatness for each skinfold equation were: P, 2.0 and 4.9; D-R, 4.2 and 6.6; D-W, 7.1 and 8.4; and, J-P, 0.7 and 4.4. With the exception of the latter equation, all significantly overestimated (p less than 0.01) hydrostatically-determined percent body fatness. CONCLUSION: Select skinfold equations may result in a marked overestimation of body fatness in formerly obese patients.

Contemporary cardiac rehabilitation services.

Major changes will be required in the components and delivery of cardiac rehabilitation services in the era of managed care. These include restructuring and amplifying the coronary risk reduction services that are currently provided, and offering group and home-based cardiac rehabilitation services to increase their availability.

Comparison of the effects of guanadrel sulfate and propranolol on blood pressure, functional capacity, serum lipoproteins and glucose in systemic hypertension.

In a controlled, double-blind, crossover study, the effects of guanadrel sulfate and propranolol on blood pressure (BP) and selected cardiopulmonary and metabolic variables were compared in 15 physically active and moderately hypertensive subjects. Guanadrel sulfate reduced systolic and diastolic BP at rest by -16 and -15 mm Hg, and at maximal exercise by -33 and -13 mm Hg, respectively (p less than 0.005), without affecting submaximal oxygen consumption (VO2), maximal VO2, ventilatory threshold, forced vital capacity, forced expiratory volume in 1 second, or fatigue, as assessed by perceived exertion. In contrast, propranolol significantly decreased diastolic BP at rest (-16 mm Hg) and systolic BP at maximal exercise (-44 mm Hg); however, it significantly decreased submaximal VO2 (-3.9 ml.kg-1.min-1), maximal VO2 (-3.9 ml.kg-1.min-1), ventilatory threshold (-0.3 liters.min-1), minute ventilation at submaximal exercise (-7.3 liters.min-1), forced expiratory volume in 1 second (-0.27 liters), and concomitantly increased the rating of perceived exertion at maximal exercise (1.9 U). Guanadrel sulfate was also associated with significant decreases in mean fasting plasma glucose and total serum cholesterol, whereas propranolol resulted in an increase in serum triglycerides (p less than 0.05). In contrast to propranolol, guanadrel sulfate appears to decrease BP without evoking negative metabolic consequences or impairing exercise tolerance.

Physiologic responses to recumbent versus upright cycle ergometry, and implications for exercise prescription in patients with coronary artery disease.

To clarify the influence of body position on exercise prescription, 14 men (mean age +/- standard deviation 60.0 +/- 6.1 years) with coronary artery disease who underwent randomized recumbent and upright cycle ergometer tests to volitional fatigue were studied. At 100 watts, heart rate (HR), systolic blood pressure, oxygen consumption (VO2), rate pressure product and rating of perceived exertion were greater (p less than 0.05) in the upright than in the recumbent position. At peak exercise, however, these variables were not significantly different. Regressions of relative HR versus VO2 for recumbent and upright cycle ergometry were comparable: y = 1.24x - 32.7 and y = 1.26x - 31.5, respectively, where y = % maximal VO2, and x = % maximal HR. These findings indicate that recumbent exercise prescriptions may be based on the peak HR and VO2 values obtained during upright cycle ergometry, and vice versa. However, differences in the cardiorespiratory responses at submaximal exercise preclude the interchangeability of upright and recumbent training work rates.

Program participation, exercise adherence, cardiovascular outcomes, and program cost of traditional versus modified cardiac rehabilitation.

Common concerns with the traditional protocol (TP) for cardiac rehabilitation include suboptimal program participation, poor facilitation of independent exercise, the use of costly continuous electrocardiographic (ECG) monitoring, and lack of insurance reimbursement. To address these concerns, a reduced cost-modified protocol (MP) was developed to promote independent exercise. Eighty low- to moderate-risk cardiac patients were randomized to a TP (n = 42) or a MP (n = 38) and were compared over 6 months on program participation, exercise adherence, cardiovascular outcomes, and program costs. During month 1, patients followed identical regimens, including 3 ECG-monitored exercise sessions/week, with encouragement to achieve >/=5 thirty-minute sessions/week. In week 5, the TP continued with a facility-based regimen including 3 exercise sessions/week for 6 months and used ECG monitoring the initial 3 months. The MP discontinued ECG monitoring in week 5 and were gradually weaned to an off-site exercise regimen that was complemented with educational support meetings and telephone follow-up. Compared with TP patients, MP patients had higher rates of off-site exercise over 6 months (p = 0.05), and total exercise (on site + off site) during the final 3 months (p = 0.03). Also, MP patients were less likely to drop out (p = 0.05). Both protocols promoted comparable improvements in maximal oxygen uptake (p <0.05), blood lipids (p <0.001), and hemodynamic measurements (p <0.002). The MP cost $738 less/patient than the TP and required 30% less staff (full-time equivalents). These results suggest that a reduced cost MP was as effective as an established TP in improving physiologic outcomes while demonstrating higher rates of exercise adherence and program participation. Thus, the MP or a similar protocol has applicability to hospitals with large capitated or managed care populations to provide cost-effective cardiovascular risk reduction to patients.

Aerobic and myocardial demands of lawn mowing in patients with coronary artery disease.

Lawn mowing approximates 4 to 6 METs and may evoke heart rate and systolic blood pressure responses that approach and exceed those attained during maximal exercise testing. The excessive cardiac demands may be deceptively camouflaged by the moderate aerobic requirements and perceived effort.

Effect of spinal cord injury on the heart and cardiovascular fitness.

The use of various FES protocols to encourage increases in physical activity and to augment physical fitness and reduce heart disease risk is a relatively new, but growing field of investigation. The evidence so far supports its use in improving potential health benefits for patients with SCI. Such benefits may include more efficient and safer cardiac function; greater stimulus for metabolic, cardiovascular, and pulmonary training adaptations; and greater stimulus for skeletal muscle training adaptations. In addition, the availability of relatively inexpensive commercial FES units to elicit muscular contractions, the ease of use of gel-less, reusable electrodes, and the increasing popularity of home and commercial upper body exercise equipment mean that such benefits are likely to be more accessible to the SCI population through increased convenience and decreased cost. The US Department of Health and Human Services has identified those with SCI as a "special population" whose health problems are accentuated, and so need to be specifically addressed. FES presents "a clear opportunity.... For health promotion and disease prevention efforts to improve the health prospects and functional independence of people with disabilities." As a corollary to this, the Centers for Disease Control and Prevention have recommended the development of techniques to prevent or ameliorate secondary disabilities in persons with a SCI. Patients with SCI have an increased susceptibility to cardiac morbidity and mortality in the acute and early stages of their injury. Most of these patients make an excellent adaptation except when confronted with infection or hypoxia. SCI by itself does not promote atherosclerosis; however, in association with multiple secondary conditions related to SCI, along with advancing age, patients with SCI are predisposed to relatively greater risk of heart disease. The epidemiologic significance of this is reflected in demographic studies that indicate an increasing number of SCI patients becoming aged. Currently 71,000 (40%) of the total 179,000 patients with SCI living in the United States are older than 40 years, and 45,000 have injuries sustained more than 20 years earlier. In addition, new injuries in the older population are increasing (currently 11% of all injuries), and some of these new patients with SCI already have pre-existing cardiac disease. Studies have demonstrated that improved lifestyle, physical activity, lipid management, and dietary restrictions can affect major risk factors for coronary artery disease. Therefore an aggressive cardiac prevention program is appropriate for patients with SCI as part of their rehabilitation. At a given submaximal workload, arm exercise is performed at a greater physiologic cost than is leg exercise. At maximal effort, however, physiologic responses are generally greater in leg exercise than arm exercise. Arm exercise is less efficient and less effective than lower body exercise in developing and maintaining both central and peripheral aspects of cardiovascular fitness. The situation is further compounded in SCI because of poor venous return as a result of lower-limb blood pooling, as a result of lack of sympathetic tone, and a diminished or absent venous "muscle pump" in the legs. This latter mechanism perhaps contributes the greatest diminution in the potential for aerobic performance in the SCI population. Obtaining a cardiopulmonary training effect in individuals with SCI is quite possible. Current studies indicate decreases in submaximal HR, respiratory quotient, minute ventilation, and oxygen uptake, with increases in maximal power output, oxygen uptake, minute ventilation, and lactic acid. Individuals with SCI have been shown to benefit from lower limb functional electrical stimulation (FES)-induced exercise. Studies have consistently reported increases in lower limb strength and cycle endurance performance with these protocols, as well as improvements in metabolic and

Recurrent ventricular fibrillation in a marathon runner during exercise testing.

We report a case of a marathon runner who presented with chest tightness, ST-segment depression, and ventricular fibrillation following treadmill exercise testing. At cardiac catheterization, the patient was found to have an isolated lesion in the left anterior descending (LAD) artery that was hemodynamically insignificant by accepted angiographic and coronary flow reserve standards. Ventricular fibrillation was thought to be idiopathic, and an implantable cardioverter defibrillator was placed. Chest pain and ST-segment depression followed by ventricular fibrillation was reproduced during follow-up treadmill testing, prompting reconsideration of the original diagnostic hypothesis. A coronary stent was deployed in the LAD artery. The patient has been asymptomatic and arrhythmia free during follow-up treadmill testing and recreational running.

Safe load carrying after uncomplicated myocardial infarction: a simple prescriptive method.

Measuring maximal handgrip strength at the time of hospital discharge provides a simple method for prescribing load holding and load carrying and patients who have had myocardial infarction.

Exercise conditioning and cardiopulmonary fitness in cystic fibrosis. The effects of a three-month supervised running program.

Exercise intolerance is common in cystic fibrosis (CF). We examined the effects of a supervised three-month running program on exercise tolerance, pulmonary function, cardiorespiratory fitness (peak oxygen consumption), and respiratory muscle endurance in CF patients. We studied 31 patients, 21 exercise and ten control, aged 10 to 30 years, with pulmonary involvement ranging from mild to severe. The exercise and control groups were not significantly different with respect to age, sex, pulmonary function, exercise tolerance, or cardiorespiratory fitness. After three months of physical conditioning, the exercise group had significantly increased exercise tolerance and peak oxygen consumption and significantly lower heart rates for submaximal work loads, while the nonexercising (control) group was unchanged in all these variables. The FEV1 decreased significantly in the control group. There were no other significant changes in pulmonary function in either the control or exercise group. Respiratory muscle endurance increased significantly in the exercise patients, and did not change in the control patients. There were no adverse effects of the program. The data suggest that a supervised running program can increase CF patients' exercise tolerance and cardiorespiratory fitness, perhaps in part by increasing respiratory muscle tolerance. The effects of a much longer program deserve study.

Exercise testing, training and arm ergometry.

Standard exercise testing and training methods require leg work, but alternative methods involving arm work appear to be particularly applicable for selected subjects. An understanding of the physiology of upper extremity exercise and of the implications for arm exercise testing and training will assist in the diagnostic and functional evaluation and prescription of exercise. The cardiorespiratory and haemodynamic responses to submaximal and maximal arm and leg exercise are reviewed and practical information and guidelines for the recommendation of arm exercise testing and training in wheelchair-confined individuals, normal subjects, and patients with coronary heart disease are provided.

Delayed progression or regression of coronary atherosclerosis with intensive risk factor modification. Effects of diet, drugs, and exercise.

Until the mid 1980s, secondary prevention of coronary atherosclerosis focused primarily on early ambulation, exercise training, and a 'prudent' diet. These regimens generally resulted in improved functional capacity, reduced myocardial demands at submaximal workrates, and modest decreases in cardiovascular mortality. However, reinfarction rates and the course of atherosclerotic heart disease remained largely unchanged with traditional treatment or usual care. Contemporary studies now suggest that multifactorial risk factor modification, and especially more intensive measures to control hyperlipidaemia with diet, drugs, and exercise, may slow, halt, and even reverse the progression of atherosclerotic coronary artery disease. Added benefits include a reduction in anginal symptoms, decreases in exercise-induced myocardial ischaemia, fewer recurrent cardiac events, and a diminished need for coronary revascularisation procedures. Several mechanisms may contribute to these improved clinical outcomes, including partial (albeit small) anatomic regression of coronary artery stenoses, a reduced incidence of plaque rupture, and improved coronary artery vasomotor function. These findings suggest a new paradigm in the treatment of patients with coronary artery disease.

Prescription of resistance training for healthy populations.

Although there are well documented protective health benefits conferred by regular physical activity, most individuals of all ages are not physically active at a level for sufficient maintenance of health. Consequently, a major public health goal is to improve the collective health and fitness levels of all individuals. The American College of Sports Medicine (ACSM) and other international organisations have established guidelines for comprehensive exercise programmes composed of aerobic, flexibility and resistance-exercise training. Resistance training is the most effective method available for maintaining and increasing lean body mass and improving muscular strength and endurance. Furthermore, there is an increasing amount of evidence suggesting that resistance training may significantly improve many health factors associated with the prevention of chronic diseases. These health benefits can be safely obtained by most segments of the population when prescribed appropriate resistance-exercise programmes. Resistance-training programmes should be tailored to meet the needs and goals of the individual and should incorporate a variety of exercises performed at a sufficient intensity to enhance the development and maintenance of muscular strength and endurance, and lean body mass. A minimum of 1 set of 8 to 10 exercises (multi-joint and single joint) that involve the major muscle groups should be performed 2 to 3 times a week for healthy participants of all ages. More technical and advanced training including periodised multiple set regimens and/or advanced exercises may be more appropriate for individuals whose goals include maximum gains in strength and lean body mass. However, the existing literature supports the guidelines as outlined in this paper for children and adults of all ages seeking the health and fitness benefits associated with resistance training.

Physical activity for the chronically ill and disabled.

Exercise prescription principles for persons without chronic disease and/or disability are based on well developed scientific information. While there are varied objectives for being physically active, including enhancing physical fitness, promoting health by reducing the risk for chronic disease and ensuring safety during exercise participation, the essence of the exercise prescription is based on individual interests, health needs and clinical status, and therefore the aforementioned goals do not always carry equal weight. In the same manner, the principles of exercise prescription for persons with chronic disease and/or disability should place more emphasis on the patient's clinical status and, as a result, the exercise mode, intensity, frequency and duration are usually modified according to their clinical condition. Presently, these exercise prescription principles have been scientifically defined for clients with coronary heart disease. However, other diseases and/or disabilities have been studied less (e.g. renal failure, cancer, chronic fatigue syndrome, cerebral palsy). This article reviews these issues with specific reference to persons with chronic diseases and disabilities.

Cardiovascular evaluation of the athlete. Issues regarding performance, screening and sudden cardiac death.

Recent studies have reported ECG anomalies and a high prevalence of exercise-related arrhythmias among well trained, apparently healthy endurance athletes with superior levels of cardiorespiratory fitness. The occurrence of sudden and premature cardiac deaths in amateur and professional athletes, who appear to embody all of the virtues of health and fitness, ahs raised our consciousness regarding the underlying atherosclerotic or nonatherosclerotic causes, and the need for, and extent of, preparticipation screening in competitive athletes. It appears that strenuous physical activity may trigger acute cardiovascular events in some athletes. Coronary artery disease is the most frequent autopsy finding in those over the age of 35 years who die suddenly. In contrast, structural cardiovascular abnormalities, including hypertrophic cardiomyopathy and malformations of the coronary arteries, are the major cause of sudden death in younger athletes. This article reviews these issues, with specific reference to the assessment of cardiorespiratory fitness, legal and prohibited performance-altering medications, the pathophysiological basis of exertion-related untoward events, the athlete at risk, limitations of conventional screening programmes and contemporary recommendations to identify latent cardiovascular disease in athletic populations.

Introduction: physiologic adaptations to exercise training in cardiac patients: contemporary issues and concerns.

This symposium dealt with contemporary issues and concerns in cardiac rehabilitation. Selected topics included: the potential of exercise training to enhance coronary collateral circulation; safety and efficacy of high intensity training; influence of beta-blocking agents on exercise prescription and trainability; value of physical conditioning in patients with left ventricular dysfunction or cardiac transplantation; and the effect of exercise on serum lipids and lipoproteins. Each article attempted to assimilate the physiologically germane literature in an area and provide the reader with associated clinical and practical implications.

Exercise training and coronary collateral circulation.

This review examines the potential for an exercise-induced increase in coronary collateral circulation, with specific reference to the role and functional significance of collateral vessels, highlighting animal and human studies in particular, and their inherent methodological limitations. Exercise training may enhance myocardial oxygen supply by promoting transient periods of myocardial ischemia, a potent trigger of collateral growth. Some human studies have shown that moderate-to-high intensity training can result in a higher double product at the onset of angina and/or ischemic ST-segment depression, suggesting that myocardial oxygen supply has increased. Attempts to use thallium-201 exercise scintigraphy to assess myocardial perfusion before and after a physical training program have produced conflicting data, whereas angiographic studies in group trials have, without exception, yielded disappointing results. Thus, direct evidence that exercise stimulates collateralization in humans is lacking.