Comparison of cardiovascular risk in maximal isometric and dynamic exercise

With the hypothesis that isometric exercise testing offers important clinical information yet is neglected because of overemphasis on its risk, we compared it with dynamic testing for variables indicative of myocardial ischemia. In a medical office, 287 patients were each subjected once to both a one-minute maximal handgrip stress test and maximal treadmill test while monitored noninvasively for cardiovascular responses. Systolic blood pressures usually increased more with the treadmill test, diastolic more with the handgrip. The treadmill tests caused greater mean heart rate and rate-pressure products, as well as more ST segment displacements, arrhythmias, and symptoms and signs. However, there were some unpredictable individual differences in the isometric blood pressure responses. Isometric testing is easy and useful and, if properly monitored, causes less risk to the patient than dynamic testing.     

Haemodynamic effects of prazosin combinations during dynamic and isometric exercise

Haemodynamic effects of atenolol 50 mg, clonidine 0.15 mg, and prazosin 5 mg, given twice daily, and of the combinations atenolol + prazosin and clonidine + prazosin were studied in 8 hypertensive outpatients. Measurements were made at rest, during isometric sustained handgrip and submaximal ergometer work in mostly double-blind and cross-over fashion. Given individually atenolol and prazosin lowered resting supine blood pressure. The addition of prazosin increased the antihypertensive effects of atenolol but not of clonidine. At the end of the isometric exercise atenolol and prazosin given alone both lowered diastolic blood pressure as compared to respective pretreatment values. During handgrip prazosin contributed a little, but not much, to the antihypertensive effects of atenolol and clonidine. During dynamic exercise atenolol, clonidine, and prazosin given alone each lowered blood pressure, prazosin decreasing diastolic blood pressure in particular. Prazosin added to the antihypertensive effect of atenolol more than that of clonidine. Echocardiographic measurements revealed no significant differences between treatments at rest. During handgrip the mean velocity of left ventricular circumferential muscle fibre shortening was reduced by atenolol as compared to pretreatment values. We conclude that atenolol + prazosin may help the patients to maintain adequate haemodynamics during daily physical stresses whilst the combination prazosin + clonidine may not offer any particular advantages.     

Blood pressure response to isometric exercise in patients with peripheral atherosclerotic disease

BACKGROUND: The purpose of this study was to compare the circulatory responses to isometric exercise in patients with peripheral atherosclerotic disease (PAD) with healthy controls. METHODS: Eleven patients with diagnosed PAD, a control group of eleven healthy young adults, and a control group of eleven healthy age-matched adults participated. Blood pressure, heart rate, stroke volume, cardiac output, blood velocity in the brachial artery, acral skin perfusion was continuously recorded and total peripheral resistance calculated before, during and after 2 min of 40% maximum voluntary contraction of the forearm. RESULTS: At rest we found a consistently higher level of mean arterial pressure (MAP) and systolic pressure (SP) in the elderly, both PAD patients and elderly controls, compared with the young controls. We found no significant difference in diastolic blood pressure. Two minutes isometric handgrip exercise induced a similar increase in MAP in all three groups (patients 32.6 (17.9) mm Hg [mean (SD)], young control group 25.3 (8.9) mm Hg, age-matched control group 36.1 (10.6) mm Hg). No significant differences were found in the other measured cardiovascular variables during isometric handgrip. Increased TPR is the main factor contributing to the increase in blood pressure in all three groups. CONCLUSION: Our study indicates that the pressor response continues to be well regulated with age, also when the cardiovascular system is altered by marked atherosclerosis. The consequence is that both PAD patients and elderly controls reach higher SP values during isometric exercise due to higher SP baseline values.     

脉冲振荡法测定慢性阻塞性肺病呼吸阻抗的应用价值探讨

目的：探讨呼吸阻抗对慢性阻塞性肺病的诊断价值。方法：185例健康人和446例慢性阻塞性肺病患者进行脉冲振荡肺功能测定，并与常规肺通气功能比较。结果：慢性阻塞性肺病患者与健康人相比，呼吸总阻抗、周边阻力、共振频率、总气道阻力、周边气道阻力均显著增高，电抗明显降低，仅电抗随慢性阻塞性肺病严重程度增加而降低。慢性阻塞性肺病患者呼吸总阻抗、周边阻力、共振频率、总气道阻力、周边气道阻力与肺通气功能呈负相关，电抗呈正相关，共振频率的相关性最为密切。以共振频率〉15Hz为标准诊断慢性阻塞性肺病时，其灵敏度、特异度综合判断为最好的脉冲振荡肺功能指标。R实测值／预计值（％）〉150％者灵敏度高。结论：脉冲振荡肺功能测定可用于慢性阻塞性肺病的诊断，共振频率为诊断慢性阻塞性肺病气流受限最敏感的指标，电抗是判断慢性阻塞性肺病严重程度的最好指标。     

Effects of chronic atenolol therapy on cardiovascular response to isometric exercise in essential hypertension

Cardiovascular response to 2 min of isometric handgrip exercise at 50% of maximum voluntary contraction was studied echocardiographically in 10 essential hypertensives, before and during treatment with atenolol for a mean of 2 months. The patients responded with increases in heart rate, systolic and diastolic blood pressures, cardiac output and calculated triple product, no changes in stroke volume and total peripheral resistance, and decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle before treatment. Chronic atenolol therapy attenuated the increases in heart rate, blood pressure and triple product, and the decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle but resulted in a marked increase in total peripheral resistance. The pressure response and triple product rise in response to isometric handgrip exercise were also decreased. This suggests an obvious advantage to hypertensive patients who may, therefore, be protected from the risk of cardiovascular complications following isometric exercise.     

Left ventricular response to graded isometric exercise in patients with coronary heart disease

Summary. The effects of graded isometric exercise on left ventricular performance were characterized in 11 male patients (53 ± 2 years) with coronary artery disease (CAD) and in 12 normal subjects (11 male and one female, 36 ± 5 years). The echocardiographic indices of left ventricular function at rest were similar in both groups. Heart rate and blood pressure increased significantly in both groups in response to 40 and 60% of handgrip maximal voluntary contraction (MVC). Left ventricular end-diastolic dimension increased significantly (from 50 ± 1 to 56 ± 1 mm; P < 0·01) with 60% of MVC in CAD group but not in the healthy subjects. The patients with CAD also exhibited significant (P < 0·01) increases in end-systolic dimension (from 34 ± 1 to 40 ± 2 with 40% and to 44 ± 1 mm with 60% MVC). End-diastolic and end-systolic dimensions did not change during isometric exercise in the healthy subjects. Mean velocity of circumferential shortening (mV_CF) increased with 60% MVC in normal subjects. In the CAD group mV_CF decreased significantly (from 1.08 ± 0·06 to 0·86 ± 0·06 with 40% and to 0·74 ± 0·04 d·s^-1 with 60% MVC; P < 0·01). At comparable mean blood pressures, mV_CF was significantly lower in the CAD group than in normal subjects. These results demonstrate that progressive deterioration of left ventricular function during increasing levels of isometric exercise in patients with CAD can be detected with echocardiography.     

Effect of enalapril at rest and during isometric and dynamic exercise in essential hypertensive patients

Vasodilator drugs reduce peripheral vascular resistance but lead to a secondary baroreflex-mediated chronotropic effect. After angiotensin-converting enzyme inhibition, blood pressure falls without associated tachycardia. In a previous study it was observed that enalapril increased vagal tone in essential hypertensive patients. In order to evaluate the effect of enalapril on sympathetic stimulation 10 mild to moderate hypertensive patients were studied during static (hand grip) and dynamic exercise (bicycle ergometer), after 2 weeks of placebo and after 1 month of treatment with 20-40 mg enalapril once daily. Enalapril significantly reduced blood pressure and the rate-pressure product at rest and at peak dynamic exercise. There was no effect on supine and maximal heart rate. Enalapril also significantly reduced blood pressure during hand grip, but did not interfere with the rate of the increase. Thus, enalapril does not seem to interfere with sympathetic adaptation to stress.     

Cardiovascular responses to low-intensity isometric handgrip exercise in coronary artery disease: effects of posture

BackgroundCoronary artery disease (CAD) lead to cardiovascular autonomic control disfunctions that can worsen exercise and/or posture adjustments.ObjectivesTo verify the cardiovascular responses to low-intensity isometric handgrip exercise performed in different postures in CAD patients. This study tested the hypothesis that the posture influences the cardiovascular responses during isometric handgrip exercise and that the presence of CAD leads to greater cardiovascular stress during this type of exercise.MethodsWe investigated cardiovascular responses to isometric handgrip exercise in 15 CAD patients (CADG) and 15 health matched-control (CG). The subjects performed isometric handgrip exercise at 30% of maximum voluntary contraction until exhaustion in SUPINE, SITTING and STANDING positions. Systolic arterial pressure, diastolic arterial pressure, mean blood pressure, heart rate, peripheral vascular resistance, cardiac output, stroke volume and double product were measured during rest (baseline), exercise (peak value) and recovery in the 1st minute (REC1). Delta PB (ΔPB, peak minus baseline) and PR1 (ΔPR1, peak minus REC1) were calculated.ResultsHigher ΔPB and ΔPR1 of systolic and mean arterial pressure and double product were observed in STANDING when compared to SITTING and/or SUPINE. CADG showed higher ΔPB of systolic and mean arterial pressure in all postures and higher ΔPR1 of strove volume in the SITTING.ConclusionWe concluded that the posture during isometric handgrip exercise influences the cardiovascular responses with STANDING leading to higher cardiovascular stress. CAD promoted higher arterial pressure responses however these responses were physiological and expected due to the presence of disease and type of exercise.     

冠心病患者等长收缩训练的作用及机理

目的：验证等长收缩训练(IE)在冠心病康复中的疗效及机理。方法：40例冠心病患者分为IE组和动力性运动DE组。IE组每日进行IE体操和有氧训练，DE组每日进行有氧训练，每周均训练5次。两组治疗时间均为6周。测定训练前后心率、血压、体重、腰围、臀围，心电运动试验，空腹血糖、血脂和二维超声心动图，并用放免法测定前后内啡肽(强啡肽、β—内啡肽、亮氨酸脑啡肽)的变化。结果：①两组均引起体质改善，但IE组腰围下降、肌力增加、最大运动时间增加和TG下降更为明显。②IE组定量运动时心血管反应下降。③IE组脑啡队和β—内啡肽明显增加。结论：冠心病患者IE训练可以安全有效地改善体质，提高最大运动能力，降低定量运动心血管反应，其机理与L—EK和β—END增加有关。     

Haematological and hormonal responses to dynamic exercise in patients with chronic airway obstruction

The influence of exercise on hormonal and total white blood cells (WBC), lymphocytes (L). Granulocytes (GR), and platelet (P) count responses was studied in: twenty-five patients with chronic airway obstruction (CAO, 47 +/- 1.8 years, mean +/- SEM) and thirteen normal subjects (N, 36 +/- 2.6 years). They performed a submaximal (40 W) and a maximal exercise (VO2max). Arterial blood samples were taken at rest, 40 W, and VO2max. [H+], PaCO2, PaO2 haematocrit (Hct), [Hb], P, total platelet volume (TPV), WBC, GR, L, and total red blood cells (RBC) were measured. At rest, WBC, GR, P and TPV were higher in CAO patients, whilst PaO2 and cortisol were lower. At 40 W, when compared to values obtained at rest, WBC, GR, L, P and TPV were increased in both groups; WBC, GR, P and TPV were higher in CAO patients. VO2max of CAO patients represented 54% of that of controls. At VO2max, Hct, [Hb] and RBC were approximately 10% higher than at rest in both groups, whilst changes were more significant in normals for WBC (CAO = 55%, N = 76%), lymphocytes (CAO = 83%, N = 105%), GR, (CAO = 37%; N = 51%), platelets (CAO = 23%, N = 29%), TPV (CAO = 25.4%, N = 35%), [H+] (CAO = 43%, N = 38%) and ACTH (CAO = 82%, N = 139%). PaO2 and cortisol did not differ between groups. PaCO2 and platelets however, were higher in the CAO group.(ABSTRACT TRUNCATED AT 250 WORDS)     

The assessment of adaptation potential of circulatory system in non-coronarogenic myocardial disease

Adaptive potential of the circulatory system was estimated in 223 patients with non-coronary myocardial lesions (80 patients had spinal osteochondrosis with cardialgia, 78 patients were obese and 65 patients had neurocirculatory asthenia of the cardial type) in tests with submaximal exercise. 21 healthy subjects served control. It was found that submaximal exercise in rehabilitation does not change the adaptive potential in healthy subjects, lowers this potential in patients with neurocirculatory asthenia and raises in obese patients.     

慢性阻塞性肺疾病缓解期患者的健康教育及康复锻炼

目的:介绍慢性阻塞性肺疾病(COPD)缓解期患者的健康教育及康复锻炼技术。方法:对86例COPD缓解期患者进行健康教育及康复锻炼。结果:81例患者血气分析及肺功能指标较前改善,症状缓解出院,5例并发Ⅱ型呼吸衰竭死亡。结论:COPD缓解期实施有效的健康教育及康复锻炼可延缓病情进展,对提高患者的生活质量具有重要意义。     

Oxygen therapy and exercise response in lung disease

Lung disease affects exercise performance through a number of mechanisms, including hypoxemia, abnormal ventilatory mechanics, abnormal ventilatory muscles, abnormal ventilatory patterns, abnormal right heart function and subjective dyspnea. Supplemental oxygen improves hypoxemia and thus improves exercise impairment resulting from hypoxemia-related reductions in oxygen delivery. Supplemental oxygen also reduces exercise ventilation. This, in turn, reduces ventilatory muscle work, and the concomitant permissive hypercapnia may have beneficial effects at the cellular level. Additionally, in obstructive disease patients, an improved ventilatory pattern may reduce air trapping. Supplemental oxygen may also improve right ventricular dysfunction in patients with underlying right ventricular dysfunction. Finally, supplemental oxygen may reduce dyspnea caused by oxygen-related carotid body activity. Important questions remain. First, is long-term oxygen use of benefit in patients with only exercise hypoxemia? Second, is exercise conditioning possible in patients with exercise hypoxemia? Third, does supplemental oxygen enhance exercise conditioning efforts in those patients with CLD but without exercise hypoxemia? If the answer to this last question is yes, what selection criteria should be used to identify those who would benefit? The answers to all of these questions will have enormous impact on our approach to the optimal management of CLD patients.     

The physiologic sequelae of chronic dynamic exercise

The physiologic results of acute dynamic exercise include complex neurologic, hormonal, pulmonary, and cardiovascular adjustments that provide an integrated response perfectly matching oxygen supply with oxygen demands. Long-term repeated bouts of dynamic exercise of sufficient intensity and duration yield predictable changes in anatomy and physiology. These changes affect active skeletal muscle and the heart. Changes in skeletal muscle include an increased capillary blood volume, increased mitochondrial density, increased oxidative pathway enzymes, and more efficient regulation of blood flow. These adaptations result in an increased oxidative capacity and more favorable fuel utilization. Oxygen extraction increases, accounting for up to 50 per cent of the increased maximal oxygen consumption, and endurance improves. Following chronic dynamic exercise the heart beats slower and has a larger stroke volume at rest and throughout a broad range of work intensities. The maximal cardiac output increases substantially, accounting for up to 50 per cent of the increased maximal oxygen consumption. The metabolic and biochemical changes found in skeletal muscle are not found in cardiac muscle. Changes found in isolated cardiac muscle do not always correlate with heart performance. The separation of central and peripheral factors in assessing heart performance is difficult because preload and afterload are major determinants of heart function and are altered by chronic dynamic exercise. Ischemia is a major stimulus for the development of coronary collateral vessel development in animals. Because dynamic exercise does not induce ischemia in normal humans, collateral vessel development may only occur in those with coronary heart disease. However, there is no convincing evidence that chronic dynamic exercise results in physiologically important coronary collateral vasculature in patients with angina. Improved work capacity is predictable following chronic dynamic exercise in patients with coronary heart disease. Although the rate pressure product that produces angina does not change following training, heart rates are lower at matched absolute workloads and the maximal consumption of oxygen increases. Changes in heart function are largely secondary to peripheral changes in these patients.     

Sexuality in chronic lung disease

Multiple factors converge to cause sexuality and intimacy problems in individuals who have chronic lung disease. It is imperative that clinicians include in their discussions with patients the ways they can maintain their sexual lives in the face of chronic lung diseases such as chronic obstructive pulmonary disease and lung cancer. Providing patients and their partners with information on ways to enhance their overall physical functioning, as well as discussing the many pharmacologic and nonpharmacologic methods available to maintain healthy sexual lives is critical to maintaining quality of life. It is apparent that more research is needed so that we can help these patients and their partners continue to have quality sexual relationships.