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PubMed1995

Cardiovascular, respiratory and metabolic effects of interval training at VLA4.

The purpose of this study was to determine if training with short intervals at the velocity producing a lactate level of 4 mmol/l (VLA4) is sufficient to induce adaptations and better exercise tolerance. Five Standardbred mares (4-8 years) were interval trained on a treadmill 3 days a week for 12 weeks and subsequently detrained for 4 weeks. Standardized exercise tests were performed before, during and after the training period and muscle biopsies were taken. Measurements were made of heart rate, oxygen consumption, stride frequency, blood volume and blood lactate. Plasma volume was reduced after 2 weeks of training but then increased to the approximate pre-training value throughout the remaining training and post-training periods. No change was detected in the total cell volume whereas the total blood volume varied in consequence with the plasma volume variation. A significant reduction in heart rate response to exercise was seen after 4 weeks of training. VLA4 increased after 2 weeks of training and remained higher than the baseline value during the rest of the training period. Consequently, the blood lactate at 8 m/sec was decreased compared to baseline concentration after 8 and 12 weeks of training. The post-training VLA4 did not differ significantly either from the end of training or from the pre-training value. Mass specific oxygen consumption (VO2-200/BW) at V200 increased with training and decreased with detraining. The respiratory quotient at a velocity of 8 m/sec decreased from 1.18 +/- 0.02 before training to 1.07 +/- 0.02 (P < 0.05) at the end of training. No changes were found in muscle histo- or biochemical parameters. The results indicate that training at VLA4 is sufficient to cause adaptational changes in exercise tolerance related parameters.

Animals↗

PubMed1976

Double-blind titrated-dose comparison of metoprolol and propranolol in the treatment of angina pectoris.

The effectiveness of metoprolol in relieving angina pectoris was compared with that of propranolol at equipotent dosages in a series of 20 patients. Before double-blind periods propranolol was given in gradually increased dosages to obtain a maximal effect for each individual patient. The responses were monitored using subjective assessment based on attack rate and nitroglycerin consumption, as well as objective maximal exercise testing. Both compounds significantly increased the exercise tolerance on a bicycle ergometer, and relieved angina as assessed subjectively. No significant differences were found between the responses to metoprolol and propranolol. The mean increase in exercise tolerance amounted to 36% with metoprolol. Biochemical monitoring revealed no harmful effects. Two cases of rebound phenomenon were observed at the transition from metoprolol to placebo. It was concluded that metoprolol is a useful new cardio-selective beta-blocking compound equipotent to propranolol in the treatment of angina pectoris.

Adult↗

PubMed1987

[Anaerobic threshold: its non-invasive evaluation and relation to exertion tolerance in patients with stenocardia].

The study of changes in gas exchange, lactate and acid-base balance in 36 trained patients with angina pectoris on effort, functional class II and III during spiroergometry has demonstrated that: 1. Ventilation equivalent by oxygen is the most informative and reproducible gas exchange variable during identification of the anaerobic threshold. 2. Anaerobic threshold in patients with low exercise tolerance is reached earlier and at lower oxygen consumption (0.92 +/- 0.02 l/min) than in patients with average exercise tolerance (1.5 +/- 0.06 l/min). 3. In all the cases anaerobic metabolism activation was accompanied by the development of signs of subendocardial myocardial ischemia, which indicates that the basic cause of anaerobic threshold reduction in trained patients was deteriorated cardiac pump function during the onset of myocardial ischemia.

Acid-Base Equilibrium↗

PubMed1991

Hemodynamics and exercise capacity during pacemaker stimulation.

This review summarizes the present knowledge concerning the hemodynamic and myocardial effects of various pacing modalities with special reference to the importance of heart rate variability and atrioventricular synchronization. An adequate increase in heart rate, irrespective of atrioventricular synchronization, seems to be the most important denominator for cardiac output and exercise tolerance. Atrioventricular synchronization will add some hemodynamic benefit, which is most pronounced at rest. The importance of a rate-adaptive atrioventricular delay and a normalized ventricular activation sequence remains, however, to be fully established. Myocardial oxygen consumption does not differ during fixed rate ventricular pacing, atrial synchronous or non-synchronous rate-adaptive ventricular pacing, neither at rest nor during exercise, despite a higher cardiac output during the rate-adaptive modes. This indicates a more "economic" cardiac work with rate-adaptive pacing. Fixed rate ventricular pacing, on the other hand, may have negative long-term effects on myocardial function due to an increased cardiac sympathetic activity compared with rate-adaptive ventricular pacing, in particular during exercise. It is concluded that the majority of pacemaker-dependent patients will benefit from restored rate variability, with the atrial electrogram still being the most appropriate trigger for rate-adaptive ventricular pacing. When the atrial signal cannot be used or when it is unreliable, however, other rate-triggering signals can be used with comparable results regarding hemodynamics and exercise tolerance.

Arrhythmias, Cardiac↗

PubMed2005

[The blood pressure response to physical exertion in adults: a preliminary survey results].

UNLABELLED: Monitoring changes in blood pressure except controlling clinical symptoms and electrocardiogram during submaximal physical exertion is essential for analyzing stress test results. Taking into consideration changes in a blood pressure play an important role in diagnostic procedures and assessment of exercise tolerance in adults. The aim of this study was to assess changes in blood pressure among adults during gradually increasing physical exertion. Blood pressure assessment was conducted in every single workload during exercise stress test. The preliminary study was performed in the randomly selected group of normotensive subjects n=224 including 107 female and 117 male 25-64 years old. Study participants had no cardiovascular or other noncommunicable diseases diagnosed by a physician. To determine cardiorespiratory fitness in the examined persons the submaximal exercise stress tests on a bicycle ergometer were performed. Blood pressure measurements were obtained according to Polish Hypertension Society (2003) standards by trained technician with a sphygmomanometer during rest period and during last minute on each level of workload. RESULTS: Mean values of resting systolic and diastolic blood pressure were significantly higher in male comparing with female (125.6 +/- 12.8 mmHg vs 117.7 +/- 15.6 mmHg for systolic and 81.3 +/- 8.5 mmHg vs 76.2 +/- 8.1 mmHg for diastolic blood pressure). We found statistically significant increase of exercise systolic and diastolic blood pressure comparing with its resting level (p<0.001). For all study participants association of exercise systolic blood pressure level and workload can be illustrate by linear equation: for female systolic blood-pressure (mmHg) = 0.0500 x load (W) + 159.74 and for male systolic blood-pressure (mmHg) = 0.3917 x load (W) + 136.00. CONCLUSIONS: During gradually increasing physical exertion systolic blood pressure is rising proportionally to increasing physical exertion. Mean values of systolic blood pressure on each level of workload had strong, linear increase. This study results can be useful in clinical practice for exercise tolerance assessment in adults and helpful for identification subjects with hypertensive response to physical exertion or hypertensive patients.

Adult↗

PubMed1979

Effects of glucose-insulin-potassium infusion on the angina response during treadmill exercise.

The effects of glucose-insulin-potassium (GIK) and placebo normal saline (S) infusion on treadmill-walking time to angina, ST depression, heart rate (HR), systolic blood pressure (SBP), rate pressure product (RPP), blood glucose (G), lactate (L) and free fatty acids (FFA) were studied in 14 non diabetic patients with exertional angina. For the whole group, the post-GIK walking time to angina (393 +/- 33 sec, mean +/- SEM) was greater than the values during control GIK (319 +/- 20 sec, p less than 0.02) and post-S infusion (334 +/- sec, p less than 0.05), but circulatory and ST responses were similar in post-GIK and post-S studies. 7 of the 14 patients experienced significantly greater improvement in exercise tolerance following GIK (467 +/- 39 sec) in comparison to control GIK (313 +/- 29 sec, p less than 0.001) and post-S infusion (334 +/- 32 sec, p less than 0.005) and exercised to a higher HR, SBP and RPP after GIK than after S infusion. At the onset of angina these patients had similar ST-segment depression before and after GIK but when ST segments were assessed after GIK at the same exercise duration when angina had occurred during the control and post-S studies, there was significantly less ST depression (p less than 0.01). Of the remaining 7 patients exercise tolerance following GIK deteriorated in 3, remained unchanged in 2 and increased by 12 and 48 sec in 2 patients in comparison to post-S values. Comparison of post-GUK and post-S values for G, L and FFA for the whole group showed significantly lower resting values of FFA and post-exercise values of G following GIK infusion. The differences in clinical and circulatory responses between patients who improved and those who did not improve following GIK were not related to the angiographically determined severity of coronary artery disease or to GIK-induced metabolic changes. Results suggest that some patients with angina pectoris do benefit from GIK infusion but the response in a given patient to this therapeutic modality is unpredictable.

Adult↗

PubMed1991

[Diagnostic possibilities of hand isometric exercise in the assessment of coronary and contractile reserve of the heart in patients with unstable angina pectoris].

The potentialities of hand isometric exercise (HIE) were studied in 84 patients with unstable angina pectoris and 25 with stable angina. With HIE, the coronary and contractile reserve was measured in the patients with angina. Lower exercise tolerance was revealed in the patients with unstable angina than in those with stable one. Among the patients with unstable angina, those at risk for myocardial infarction were predominant. Lower exercise tolerance appeared as decreased "threshold" double product values and diminished myocardial contractile reserve (higher left ventricular filling pressure). HIE applied in the study evaluates the efficacy of treatment and the prediction of the disease course more accurately.

Angina Pectoris↗

PubMed1994

A new "complex exercise test" for children with cardiac diseases.

In view of the characteristics of children's play or exercise activity, we designed a new method of exercise testing for children, called the "Complex Exercise Test" (CET), which includes three kinds of exercise test: (1) a graded exercise test on the treadmill, (2) a simple bending and stretching test to evaluate momentary exercise tolerance and (3) a swimming test with the ECG in the water. The CET was applied to a total of 25 cases which included 10 cases of postoperative tetralogy of Fallot and 15 cases with ventricular premature contraction (VPC). A two-way exercise test, which included the treadmill test and the simple bending and stretching test, was also applied to 36 postoperative cases (21 cyanotic and 15 non-cyanotic), 20 VPC cases and 16 control children without any organic cardiac disorders, for a total of 72 cases. The treadmill test was useful to evaluate the maximal exercise tolerance. The simple bending and stretching test, on the other hand, seemed useful for observation of VPC changes by exercise (including postoperative VPC), since the heart rate immediately after bending and stretching exceeded that observed at the time VPC disappeared during the treadmill test, thus proving VPC disappearance by this testing. With ECG during diving, it is possible to detect VPC associated with possible risks which could not be identified by the above two methods of testing. Since each one of the three different types of exercise tests has different characteristics, it seems desirable to control children's exercise after performing the CET.

Adolescent↗

PubMed1990

[Early prognosis of work capacity in patients with ischemic heart disease after direct myocardial revascularization].

The study was designed to estimate the clinical status and exercise tolerance in 25 patients in the preoperative and early postoperative periods, as well as at weeks 6-8 of direct myocardial revascularization performed by applying microsurgical techniques. The clinical status improved in all the patients. Their exercise tolerance was increased by 67 and 106% 2-3 and 6-8 weeks after the surgery, respectively. Thus, with uncomplicated coronary artery reconstruction, the patients can perform graded physical exercise in the early postoperative period, which provides evidence for reduction of a patient's stay in hospital.

Adult↗

PubMed1995

Cardiovascular effects of prolonged growth hormone replacement in adults.

OBJECTIVES: To study the cardiovascular effects of human growth hormone (GH) replacement therapy in adults. INTERVENTION: Biosynthetic human GH given in a daily dose of 0.04 +/- 0.01 IU kg-1 for 6-18 months in an open trial. PATIENTS: Thirty-four GH-deficient hypopituitary patients on conventional replacement therapy, aged 19-67 years and with a body mass index of 18.0-410.0 kg/m2. MEASUREMENTS: Resting blood pressure, exercise tolerance, renal function and routine blood counts were assessed every 6 months. Two-dimensional echocardiography and Doppler ultrasound scanning were performed at 0, 6 and 12 months of GH therapy. RESULTS: Exercise time increased significantly on GH from 9.37 +/- 2.64 min at the start to 10.39 +/- 2.86 min (P < 0.001), 10.90 +/- 2.48 min (P < 0.001) and 11.11 +/- 0.70 min (P < 0.001) at 6, 12 and 18 months respectively. There was no change in the heart rate or in the blood pressure at rest nor at the peak of exercise. No significant changes were observed in measures of cardiac structure (left ventricular mass index, left ventricular posterior wall thickness and interventricular septal thickness), ejection fraction nor in cardiac output. Isovolumic relaxation time, a marker of diastolic function, decreased in 24 patients after 6 months on GH (from 98.6 +/- 15.9 to 89.6 +/- 15.2 ms; P < 0.03) but it was not different from baseline in the 18 patients who were restudied at 12 months. There was no significant change in the left ventricular filling neither at 6 nor at 12 months. No significant, changes were observed in plasma electrolytes, creatinine nor in blood count on GH treatment. CONCLUSIONS: Growth hormone replacement therapy in hypopituitary adults for 6-18 months produced sustained increase in exercise tolerance but was not associated with changes in cardiac structure or systolic function.

Adult↗

PubMed1997

Effects of antianginal therapy with a calcium antagonist and nitrates on dobutamine-atropine stress echocardiography. Comparison with exercise electrocardiography.

BACKGROUND: Anti-ischaemic therapy with nitrates and/or calcium channel blockers profoundly affects the results of pharmacological stress echocardiography with coronary vasodilators but the influence on catecholamine stress testing remains unsettled. AIMS: The present study aimed to assess the effects of non-beta-blocker antianginal therapy on dobutamine (up to 40 micrograms.kg-1.min-1)-atropine (up to 1 mg) stress. echo-cardiography and to evaluate whether drug-induced changes in the dobutamine atropine stress echocardiography response may predict variations in exercise tolerance. METHODS: Twenty six patients with angiographically assessed coronary artery disease (seven patients with single-, 10 with double-, and nine with triple-vessel disease) performed a dobutamine atropine stress echocardiography and an exercise electrocardiography test in random order both off and on antianginal drugs (nitrates and calcium antagonists). In doubtamine-atropine stress echocardiography, we evaluated: dobutamine time (i.e. the time from initiation of the dobutamine infusion to obvious dyssynergy), wall motion score index (in a 16-segment model of the left ventricle, each segment ranging from 1 = normal, to 4 = dyskinetic), and rate-pressure product at peak stress. RESULTS: Dobutamine-atropine stress echocardiography positivity occurred in 26 out of 26 patients off and in 23 patients on therapy (100 vs 88%, P = ns). Atropine coadministration was needed to evoke echo positivity in no patient off and in five out of 26 on therapy (0 vs 19% P < 0.01). The achieved rate pressure product during dobutamine-atropine stress echocardiography was comparable on and off therapy (17 +/- 4 vs 19 +/- 5 x 10(3) mmHg x heart rate. min-1, P = ns). Therapy induced an increase in dobutamine time (on = 16 +/- 3 vs of = 13 +/- 3 min, P < 0.01) and a decrease in peak wall motion score index (on = 1.3 +/- 0.2 vs off = 1.5 +/- 0.3, P < 0.01). The therapy induced changes in exercise time during the exercise electrocardiography test were not significantly correlated to dobutamine-atropine stress echocardiography variations in either dobutamine time (r = 0.07, P = ns), or peak rate pressure product (r = 0.24, P = ns), or peak wall motion score index (r = 0.02, P = ns). CONCLUSIONS: (1) non-beta-blocker antianginal therapy only modestly reduces dobutamine-atropine stress echocardiography sensitivity, although atropine coadministration is more often required to reach stress echo positivity under therapy; (2) therapy reduces the severity of dobutamine atropine stress echocardiography ischaemia stratified in the time and space domain, but these changes are only poorly correlated to variations in exercise tolerance.

Atropine↗

PubMed1976

Clinical correlates of coronary cineangiography in young males with myocardial infarction.

Thirty-eight men who suffered acute transmural myocardial infarction before age 40, and after recovery were New York Heart Association functional Class I or II, were studied by noninvasive means and by coronary angiography in order to determine whether these nonivasive studies could predict the presence of significant coronary artery disease remote from that felt to be responsible for the previous myocardial infarction. Patients were divided into two groups on the basis of the absence (Group I) or presence (Group II) of obstructive disease in a major coronary artery supplying myocardium remote from the prior myocardial infarction. There were 21 patients in Group I and 17 patients in Group II. They did not differ with respect to age, abnormalities of lipid or glucose metabolism, family history, history of hypertension or cigarette use, presence of obesity, or infarct localization. Ten of 17 patients in Group II had angina pectoris; only 3/21 patients in Group I had angina pectoris (p less than 0.01). All 12 patients tested in Group II had a positive maximal exercise tolerance test; only 1/17 patients tested in Group I was similarly positive (p less than 0.001). The absence of angina pectoris and the presence of a negative maximal exercise tolerance test is strong evidence against the pressure of significant CAD remote from that responsible for the prior myocardial infarction.

Adult↗

PubMed1985

Does exercise alter anaerobic threshold in coronary artery disease during beta blockade?

The effect of propranolol on cardiac patients undergoing exercise training is reported to increase exercise tolerance and maximum oxygen uptake (VO2 max) but its effect on anaerobic threshold (AT) is unknown. It was the purpose of this study to determine the role of exercise training with propranolol on AT in patients with coronary artery disease (CAD). Eight men and one woman with significant (CAD) were selected for this study. Each patient completed a maximum treadmill stress test (MTST) following the Bruce protocol on propranolol 40-160 mg/day as a control study. Cardiorespiratory variables were measured at rest and at each stage of the treadmill test. These patients underwent an exercise training programme for 12-16 weeks on the same dose of propranolol. Training sessions were for a minimum of 30-40 minutes, 3 times a week, with training heart rate of 75%-85% of the pretraining peak heart rate. Training heart rate ranged from 98 to 128 beats/min. They were retested with a MTST after the training programme, on the same dose of propranolol. AT was calculated noninvasively by measuring respiratory variables every 30 seconds in relation to work increment. AT was identified by measuring the time course of VE, VCO2, VE/VO2, etc. in relation to incremental work. The mean values of VO2, O2P and % VO2 max at AT before and after training on propanolol were as follows: VO2 = 1.43 L/min +/- .25 and 1.86 L/min +/- .44, O2P = 14.35 +/- 2.40 and 18.73 +/- 4.00 ml/beat, % of VO2 max = 68.20 +/- 6.31 and 73.59 +/- 5.84. The mean changes of VO2 O2P, and % of VO2 max were + 0.43 L/min +/- 0.20 (P < .003), + 4.38 +/- 2.55 (P < .003) and +/- 5.07% +/- 4.84 (P < .001). After exercise training on propanolol, the mean peak exercise tolerance time and absolute VO2 max increased by 2.8 min (from 9.0 to 11.8 min) (P < .001) and 22.7% (P < .007), respectively. We conclude that the increase in anaerobic threshold in patients with coronary artery disease may be due to improvement in VO2 max, increased stroke volume, and peripheral O2 extraction.

Body Weight↗

PubMed1979

Comparison of the immediate effects of five beta-adrenoreceptor-blocking drugs with different ancillary properties in angina pectoris.

We compared the immediate effects of five beta-adrenoreceptor-blocking agents in 16 patients with stable angina pectoris. Acute dose-response studies showed that all five drugs improved exercise tolerance and reduced ST-segment depression, heart rate and blood pressure by a similar degree in comparison with a placebo (P less than 0.01). Near maximum improvement in exercise tolerance occurred when the acute cumulative oral dose had reached 160 mg for propranolol and oxprenolol, 200 mg for metoprolol and tolamolol and 400 mg for practolol. When these drugs were administered as a single doses, increase in walking time before the development of angina and reduction in ST-segment depression, heart rate and systolic blood pressure all occurred within one hour and persisted for eight hours--effects markedly different from the response to a placebo (P less than 0.01). These data show that non-cardioselective agents (propranolol and oxprenolol), cardioselective agents (practolol, metoprolol and tolamolol), as well as drugs with intrinsic sympathomimetic activity (oxprenolol and practolol), were equally effective in the treatment of angina pectoris.

Adult↗

PubMed1979

Improvement of myocardial perfusion and left ventricular function after coronary artery bypass grafting in patients with unstable angina.

Changes in myocardial perfusion and left ventricular function were evaluated pre- and post-operatively (3--6 months) in 14 patients with unstable angina who underwent coronary artery bypass surgery. Perfusion was studied with intracoronary and intragraft injections of radiolabeled macroaggregated albumin particles. Of 20 abnormal perfusion areas identified preoperatively, 13 demonstrated improved perfusion post-operatively. Segmental analysis of the left ventriculogram demonstrated improved wall motion in 29 abnormally contracting segments; 18 normalized. Areas which showed improvement of left ventricular perfusion were invariably associated with improvement of left ventricular wall motion. Five patients showed improvement in perfusion and contraction in areas of apparent old myocardial infarction. Thirteen of the 14 patients had significantly less angina whether or not there was evidence of improved perfusion. However, only those patients who demonstrated improved perfusion had a significant improvement in their treadmill exercise tolerance postoperatively. Thus, patients with unstable angina have perfusion defects which may be reversed as a result of saphenous vein graft surgery. Reversal of these perfusion abnormalities results in improved left ventricular performance and better exercise tolerance postoperatively.

Angina Pectoris↗

PubMed1977

Effects of a new beta1-selective beta-blocker H 87/07 in angina pectoris.

The efficacy and toleration of a new beta1-selective beta-blocker, H 87/07, was compared with placebo in 33 patients with angina pectoris. The efficacy was evaluated using subjective assessments of attack rate and nitroglycerin consumption as well as objective assessments of exercise tolerance on a bicycle ergometer. H 87/07 significantly reduced the attack rate and the nitroglycerin consumption compared with placebo. The mean reduction amounted to 13 and 36% respectively. No significant differences were found between H 87/07 and placebo with regard to exercise tolerance. Due to high intrinsic stimulating activity (I.S.A.) H 87/07 altered the heart rate and blood pressure only slightly at rest but during exercise significant reductions were seen. Except for one patient who had cardiac decompensation on H 87/07 no side-effects of clinical importance were seen. No significant changes were seen with regard to the laboratory tests performed.

Adrenergic beta-Antagonists↗

PubMed1986

[Hemodynamic and anti-angina effects of transdermal nitroglycerin after acute and chronic administration. Additive effect of sublingual isosorbide dinitrate].

To evaluate the acute and chronic anti-anginal efficacy of a Transdermal Therapeutic System, releasing 10 mg of nitroglycerin over 24 hours (TTS 10), and possible additional effects of isosorbide dinitrate 5 mg (ISDN) sublingually (s.l.), ten patients with stable exercise-induced angina pectoris and pathological coronary angiography were studied. The protocol of the trial consisted of an initial acute study, carried out in double-blind conditions and following a cross-over design, to compare TTS 10 and placebo. Cycloergometric exercise tests were performed on the first and second day, 3 hours after dosing. After a 30 minute rest period, a sublingual 5 mg dose of ISDN was given and 15 minutes later a further exercise test was carried out. Subsequently, patients received TTS 10 in single-blind conditions for 16 days. On the 15th and 16th day, stress test was repeated, 3 hours after the application of active plasters and, 30 minutes later, a further exercise test was performed, 15 minutes after a sublingual dose of ISDN 5 mg or placebo, given in double-blind conditions and in randomized sequence. After acute and chronic administration, TTS 10 significantly improved exercise tolerance in comparison with placebo. During the first acute study, ISDN 5 mg s.l., led to a significant reduction in systolic BP, a reflex increase in heart rate and a further improvement in exercise tolerance, whether patients were on placebo or TTS.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗

PubMedDate not supplied

Diuretic therapy and exercise performance.

Drugs that induce an increased urine flow are used both legitimately (treatment of hypertension and oedema) and otherwise (rapid weight loss) in sports and exercise. There are 5 major categories of diuretic drugs based on their mechanisms and loci of action. Common to all classes is hypohydration, which has been shown to have an array of adverse effects on performance, including impaired strength, power and endurance. Postural hypotension can be particularly troublesome in the elderly. Also common to all diuretics, except those interfering with the aldosterone mechanism in the distal nephron, is hypokalaemia. Severe symptomatic hypokalaemia (serum K+ concentration less than 3.0 mmol/L) is rare except in clinical situations in which additional hypokalaemic factors are present. Moderate levels of hypokalaemia (serum K+ concentration 3.0 to 3.5 mmol/L) can increase the risk of adverse reactions as has been shown in a variety of prospective clinical studies. Hypokalaemia has effects on cardiac rhythm, muscle function and integrity, local blood flow, carbohydrate metabolism, and the blood lipid profile. Performance studies generally show diminished exercise tolerance in direct proportion to the degree of hypohydration induced. This is not the case, however, in a clinical setting of compromised cardiopulmonary function, in which diuresis has direct and indirect inotropic effects which augment exercise tolerance and decrease symptoms. The ability of the carbonic anhydrase inhibitor, acetazolamide, to induce a hyperventilatory response to the obligatory metabolic acidosis is taken advantage of in mountaineering to prevent or ameliorate the symptoms of acute mountain sickness, thereby improving exercise performance at high altitude. It is suggested that in clinical situations in which the use of a diuretic is considered appropriate, every effort be made to maintain or restore the serum concentration and the total body store of potassium to normal. To some degree this can be accomplished through diet, although potassium chloride supplements or potassium-sparing diuretics or diuretic combinations may be necessary.

Diuretics↗