Administration of slow-release nifedipine does not affect lactate threshold,hormone release during exercise,and quality of life in normal subjects

Summary In a double-blind crossover study of 10 normal healthy subjects, we examined the effects of slow-release nifedipine (nifedipine-SR, 10 mg b.i.d) administration on exercise capacity, hormone levels during exercise, and quality of life (QOL) after a 2-week treatment. Two exercise tests, a progressive exercise test and a constant work-rate exercise test, were performed. Maximal oxygen uptake (\.VO₂max) and blood lactate concentration were measured during the progressive exercise test and the exercise intensity corresponding to half lactate threshold (LT), LT, and 4 mmol/l of lactate concentration was determined. Subjects underwent 20 minutes of constant work-rate exercise at each work load, and blood lactate, plasma epinephrine, plasma norepinephrine, plasma renin activity, plasma aldosterone, atrial natriuretic peptide, plasma β-endorphin, and met-enkephalin were measured. Taking nifedipine-SR had no effect on the responses of blood pressure, heart rate, VO₂max, maximal work load, and LT compared to taking placebo. Blood lactate, plasma catecholamine, plasma renin activity, aldosterone, atrial natriuretic peptide, and β-endorphin levels increased during exercise, and there was no difference between nifedipine-SR and placebo. Met-enkephalin did not increase with either treatment. In the QOL questionnaires, no differences were noted between the two treatments. These findings suggest nifedipine-SR to be a potentially useful drug in view of the lack of effect on exercise capacity, hormone release, and QOL.     

Effects of oxygen on exertional dyspnoea and exercise performance in patients with chronic obstructive pulmonary disease

Background and objective: The results of studies on the oxygen response in patients with COPD should provide important clues to the pathophysiology of exertional dyspnoea. We investigated the exercise responses to hyperoxia in relation to dyspnoea profile, as well as cardiopulmonary, acidotic and sympathetic parameters in 35 patients with stable COPD (mean FEV₁ 46% predicted). Methods: This was a single‐blind trial, in which patients breathed 24% O₂ or compressed air (CA) in random order during two incremental cycle exercise tests. Results: PaO₂ and PaCO₂ were higher (P < 0.0001 and P < 0.05, respectively) at each exercise point while patients were breathing 24% O₂ compared with CA. At a standardized time point near peak exercise, use of O₂ resulted in reduced plasma lactate and plasma noradrenaline concentrations (P < 0.01). Peak minute ventilation/indirect maximum voluntary ventilation was similar while breathing 24% O₂ and CA. At peak exercise, the dyspnoea score, pH and plasma noradrenaline concentrations were similar while breathing 24% O₂ and CA. The dyspnoea—ratio (%) of Δoxygen uptake (peak minus resting oxygen uptake) curve reached a break point that occurred at a similar exercise point while breathing 24% O₂ or CA. Conclusions: Regardless of whether they breathed CA or 24% O₂, patients with COPD did not develop ventilatory compensation for exertional acidosis, and the pH values measured were similar. Hyperoxia during a standardized exercise protocol did not alter the pattern of exertional dyspnoea in these patients, compared with breathing CA, although hyperoxia resulted in miscellaneous effects.     

Evidence of anaerobic metabolism during low-level exercise testing in high-risk postmyocardial infarction patients

Low-level exercise testing was performed on 31 patients 7.4 +/- 2.7 days following an acute myocardial infarction. Measurements of oxygen consumption (VO2) and arterial serum lactate were made at rest and during exercise in these patients and 15 normal subjects. The patients were subdivided into finishers (F) and nonfinishers (NF) of the low-level protocol. The NF group had 2.5 +/- 6 stenosed vessels and an ejection fraction of 44 +/- 11% compared to F subjects, who had 1.4 +/- 1 vessels stenosed (p less than .001) and an ejection fraction of 54 +/- 14% (p less than .05). Finishers had significantly higher VO2 than the nonfinishers (14.5 +/- 2.5 ml/kg/min vs. 11.2 +/- 3.5 ml/kg/min p less than .01). At the end of exercise serum lactate level was 1.18 +/- .59 mM in normals, 1.43 +/- .52 mM in finishers, and 2.15 +/- .9 mM in nonfinishers. The change in serum lactate from rest to end exercise divided by the change in VO2 from rest to end exercise was .039 +/- .038 mM/ml kg per min in normals, .075 +/- .045 mM/ml kg per min in finishers (p less than .03 vs. normal), and .210 +/- .189 mM/ml kg per min for nonfinishers (p less than .001 vs. normal). These results indicate that nonfinishers produce more lactate and use less oxygen during low-level exercise, suggesting that working muscles are deriving energy by anaerobic metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of exercise on plasma viscosity in athletes and sedentary normal subjects

To assess the immediate and long-term effects of exercise on factors regulating blood flow, we measured plasma viscosity (η_p) and plasma renin activity (PRA) in 17 trained runners and 16 sedentary healthy subjects before and 10 min after graded treadmill exercise. Resting η_p was lower in runners primarily because of significantly lower fibrinogen concentration. Compared to nonrunners with similar 24-h urine electrolyte excretion rates, runners were characterized by lower PRA at rest. In view of the overall correlation between heart rate and PRA before exercise, reduced adrenergic tone was probably a major factor contributing to the lower PRA in runners. After exercise, plasma viscosity and PRA exceeded control levels, and were similar in magnitude in runners and sedentary subjects. Changes in plasma viscosity were less than expected from the degree of hemoconcentration, primarily because enhanced fibrinolysis maintained fibrinogen level constant. To the extent that plasma viscosity affects viscous flow resistance, the results suggest that tissue perfusion and oxygen delivery rate at rest are greater in trained runners than in sedentary subjects, but these variables become similar after maximum exertion.     

Hemodynamic effects of disopyramide at rest and during exercise in normal subjects

The hemodynamlc effects of disopyramide phosphate, 2.0 mg/kg body weight, given intravenously over a period of five minutes were studied at rest and during exercise in ten patients without clinical or anglographlc evidence of heart disease. Following disopyramide, the resting cardiac index was lower (4.0 ± 0.6 vs 4.3 ± 0.6 iners/min/m², mean ± 1 SO, P <0.05), while left ventricular end-dlastollc pressure (16 ± 4 vs 11 ± 4 mm Hg, P <0.001), pulmonary arterial (PA) mean pressure (20 ± 5 vs 17 ± 5 mm Hg, P <0.05), and brachlal arterial (BA) mean pressure (105 ± 8 vs 96 ± 7 mm Hg, P <0.05) were higher than the pre-infuslon resting values. During exercise, there was no change in left ventricular end-diastollc pressure while cardiac index rose from 4.0 ± 0.6 to 6.5 ± 0.6 itters/mln/m² (P <0.001) and left ventricular stroke work index increased from 62 ± 19 to 84 ± 22 gm/beat/m² (P <0.001). The normal hemodynamlc response during exercise after disopyramide despite the apparent depression of left ventricular function at rest probably reflects the positive inotroplc effect of enhanced sympathoad-renergic activity.     

Oxygen uptake versus exercise intensity: a new concept in assessing cardiovascular exercise function in patients with congenital heart disease

OBJECTIVE—To assess the relation between exercise intensity and oxygen uptake during graded exercise in paediatric patients who underwent surgical repair of congenital heart disease, and to compare it with conventional measures of aerobic exercise function.
DESIGN—Cross sectional study. Exercise testing was performed on a treadmill and gas exchange was measured on a breath by breath basis.
PATIENTS—29 patients who underwent an atrial switch operation for transposition of the great arteries (TGA) (mean (SD) age at testing 10.3 (2.5) years) and 30 patients who underwent total repair of tetralogy of Fallot (TF) (age 12.1 (3.3) years) performed graded exercise testing. Exercise responses were compared with data obtained in 24 normal controls (age 11.4 (2.6) years).
RESULTS—The slope of oxygen uptake versus exercise intensity averaged 1.50 (0.64) ml O₂/min²/kg in the patients with TGA and 1.68 (0.75) ml O₂/min²/kg after TF repair, both lower (p < 0.005) than in normal controls (2.42 (0.68) ml O₂/min²/kg). The lower slope of oxygen uptake was correlated with a subnormal value for ventilatory anaerobic threshold, which averaged 78.0 (13.3)% of normal in TGA and 85.1 (10.6)% in TF. This was associated with a steeper slope (p = 0.001) of carbon dioxide output versus oxygen uptake above the ventilatory anaerobic threshold in TGA (1.26 (0.20)) and TF (1.20 (0.18)) compared with the normal controls (1.05 (0.13)), and also a steeper slope of ventilation versus carbon dioxide in TGA (47.0 (15.4)) and TF (41.5 (13.7)) than in the controls (30.3 (8.5)).
CONCLUSIONS—Calculation of the steepness of the slope of oxygen uptake versus exercise intensity is a valid measurement of oxygen flow to the exercising tissues, which may be limited in congenital heart disease.


Keywords: congenital heart disease; exercise testing; oxygen uptake; oxygen uptake kinetics     

What limits endurance in normal children?

We have compared the results of a standard progressive maximal exercise test to those of an endurance exercise test in 22 healthy school children (13 girls, 9 boys, mean age 14.8 years) in order to examine whether it is possible to extrapolate results from a maximal test to predict their endurance capacity. All children performed a standard progressive maximal exercise test (15 W increments every minute until exhaustion) and an endurance test (individually calculated loads to mimic cycling at 20 km/h against a windforce 5 of Beaufort for 30 minutes) on 2 separate days. In both tests metabolic [oxygen uptake (Vo₂), CO₂ production, blood lactate accumulation], ventilatory [minute ventilation (V_E)], and circulatory variables were measured. From the maximal test the threshold of lactate accumulation (LT) was determined. Thirteen children were capable of enduring the 30 minute exercise (Group l), and 9 could not complete the endurance test (Group 2). These two groups were comparable with respect to age, height, and baseline lung function. Children in Group 2 had a higher mean weight (P < 0.005) than those in Group 1. Eight of the 9 children in Group 2 were girls, whereas Group 1 consisted of 5 girls and 8 boys. There was no significant difference between Group 1 and 2 in the mean values of Vo₂ max, maximal respiratory exchange ratio (R max), V_Emax, LT, oxygen pulse, and other variables obtained during the maximal exercise tests. Lactate accumulation during the endurance test in Group 2 was larger than in Group 1 (P < 0.005). This confirms that lactate metabolism is a key factor that determines endurance capacity. The endurance time also correlated significantly (P < 0.01) with the ratio between V_E and maximal voluntary ventilation (MVV). We conclude that exercise endurance in healthy children correlates with variables related to lactate metabolism. It appears that a load at or lower than the LT can be sustained for 30 minutes in the great majority of healthy children. © 1993 Wiley-Liss, Inc.     

Effects of verapamil and diltiazem on gastric emptying in normal subjects

It has been suggested that calcium-channel blockers may delay gastric emptying by inhibiting gastric smooth muscle contraction. Most reports in man, however, reveal no significant delay in gastric emptying after using nifedipine; other calcium-channel blockers have not been studied in humans to date. We studied the effects of verapamil and diltiazem on solid-phase gastric emptying in 10 healthy volunteers. Each subject underwent a radionuclide gastric emptying determination (1) without preadministered medication, (2) after verapamil 80 mg orally every 6 hr for 10 doses, and (3) after diltiazem 60 mg by mouth given as one dose. Results revealed no significant difference in gastric emptying rates after pretreatment with verapamil or diltiazem when compared with no premedication (P>0.37). We conclude that verapamil and diltiazem do not significantly delay gastric emptying in normal subjects. These data may be of clinical significance when prescribing calcium-channel blockers to patients with diseases associated with altered gastric emptying.The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of the Army or the Department of Defense.     

Acute effects of alcohol on left ventricular dynamics during isometric exercise in normal subjects

The aim of this study was to assess whether drinking social amounts of alcohol impairs myocardial contractility in normal humans. To that end, 17 healthy volunteers performed isometric handgrip exercise before and 60 minutes after an intake of 1 g/kg body weight of ethanol within 60 minutes. Left ventricular M-mode echocardiogram, systolic time intervals, and sphygmomanometric arterial blood pressure were recorded before and at the end of 4-min handgrip at 30% of maximum voluntary contraction. The blood ethanol concentration (mean +/- SD) was 24.4 +/- 2.0 mmol/liter. At rest, ethanol increased heart rate (p less than 0.05), and decreased left ventricular end-diastolic diameter (p less than 0.05), end-systolic diameter (p less than 0.01), and circumferential systolic wall stress (p less than 0.05). The indices of left ventricular performance were unchanged except for the maximum circumferential fiber shortening velocity which was increased after ethanol (p less than 0.001). The cardiac response to isometric exercise was similar before and after ethanol except that the handgrip-induced rise in systolic wall stress was smaller postingestion (p less than 0.05). This study does not support the view that drinking small to moderate amounts of alcohol brings about myocardial depression in normal humans. Although preload, afterload, and heart rate were altered by ethanol at rest, myocardial contractility was not impaired even during the afterload stress imposed by isometric exercise.     

Circulatory effects of mental stress during exercise in coronary artery disease patients

We examined the effects of mental stress during steady-state exercise on heart rate, blood pressure, pressure-rate product, and oxygen uptake in 10 coronary artery disease patients. Subjects walked at three mph with grade increases of 4% every two minutes until the target heart rate (60% peak heart rate from a previous symptom-limited exercise test) was reached. A computerized Stroop-Color-Word Test (mental stress) was added one minute after the subject reached steady-state exercise and lasted 11 +/- 4 minutes. When mental stress was added to steady-state exercise it significantly (p less than 0.01) increased the heart rate (101 +/- 15 to 108 +/- 19 beats per min), systolic (154 +/- 26 to 170 +/- 26 mmHg) and diastolic (86 +/- 10 to 92 +/- 13 mmHg) blood pressure, and pressure-rate product (158 +/- 42 to 179 +/- 48 x 10(-2)). This increase in the mean response during exercise and mental stress was not observed for oxygen uptake (17 +/- 6 to 18 +/- 5 ml/kg/min). The circulatory changes probably reflect increased sympathetic activity with both centrally mediated cardioacceleratory (and probably cardiac output) and vasoconstrictor effects during the combination of mental stress and steady-state exercise. The altered hemodynamics without concomitant changes in oxygen uptake has major implications concerning the safety of competitive exercise for people with coronary artery disease.     

Acute effect of metformin on exercise capacity in active males

Aim: Physical activity and metformin are often used concomitantly in the treatment of diabetes, even though little is known about possible interactions between these treatment modalities. This study was designed to examine the acute effect of metformin on oxygen consumption and lactate concentration during exercise. Methods: Eleven healthy, active men [mean ± s.d.: age = 29.9 ± 3.7 years; body mass index = 25.2 ± 2.8 kg/m²; maximal oxygen consumption (VO_2max) = 53.5 ± 8.9 ml/kg/min] completed a randomized, double‐blind, placebo‐controlled, crossover study. The testing protocol consisted of a standardized breakfast with metformin (1000 mg) or placebo. Three hours after breakfast, participants underwent a graded maximal exercise test on a cycle ergometer. Approximately 30 min after this exercise test, participants cycled continuously at an intensity below their ventilatory threshold for 45 min (mean exercise intensity = 69 ± 5.5% of VO_2max). Results: During the graded exercise test, average oxygen consumption was higher for the metformin condition (2.9 vs. 2.8 l/min, p = 0.04); however, there was no treatment effect on VO_2max or ventilatory threshold. During continuous exercise, lactate was lower for the metformin condition (4.7 vs. 5.4 mmol/l, p = 0.05). Following a standardized lunch, glucose concentrations were lower in the metformin compared with the placebo condition (5.8 vs. 6.4 mmol/l, p = 0.04). Conclusion: A single dose of metformin does not acutely influence maximal oxygen consumption or ventilatory threshold in healthy active males. The lower lactate concentration observed during continuous exercise with metformin was an unexpected finding considering that, in the resting state, metformin has been previously associated with a modest increase in lactate concentrations.     

30 d头低位卧床期间体育锻炼对立位耐力、运动耐力和心率变异性的影响

目的:观察和比较30 d -6°头低位卧床期间下肢肌力训练和自行车功量计训练对立位耐力、最大运动时间、体质量以及心率变异性（HRV）的影响,旨在进一步明确体育锻炼方法对失重所致心血管失调的对抗效果,为制定我国载人航天飞行时航天员失重对抗方案提供实验依据。方法:15名男性健康被试者,随机分为对照组、下肢肌力训练组和自行车功量计训练组3组,每组5人。对照组仅-6°头低位卧床30 d,不进行任何处理,下肢肌力训练组和自行车功量计训练组在30 d卧床期间分别进行下肢肌力训练和自行车功量计训练。实验前后测量立位耐力、最大运动时间,实验期间测量体质量及HRV。结果:卧床30 d,对照组的立位耐力较卧床前显著降低（P<0.01）,而下肢肌力训练组和自行车功量计训练组的立位耐力较卧床前有所降低,但未达到显著水平。卧床第30 d,对照组和下肢肌力训练组的最大运动时间较卧床前显著降低（P<0.05）,而自行车功量计训练组较卧床前无明显变化,且较对照组和下肢肌力训练组显著升高（P<0.05）。卧床期间,对照组体质量较卧床前有降低趋势,下肢肌力训练组有升高趋势,自行车功量计训练组无明显变化;卧床第10 d,下肢肌力训练组体质量较对照组显著增加（P<0.05）。HRV分析发现,卧床期间对照组归一化低频（LFn）、低频功率与高频功率的比值（LF/HF）较卧床前有升高趋势,归一化高频（HFn）有降低趋势,两锻炼组上述指标变化与对照组相似。结论:30 d头低位卧床可引起立位耐力和运动耐力显著降低,心血管自主神经调节均衡性发生改变。下肢肌力训练在一定程度上能够提高模拟失重后的立位耐力,而自行车功量计训练可提高模拟失重后的立位耐力和运动耐力。     

Peak oxygen uptake during exercise in mitral stenosis with sinus rhythm or atrial fibrillation: lack of correlation with valve area: A study in 70 patients

Although the haemodynamic response during submaximal supineexercise in mitral stenosis has been well described, the determinantsof peak oxygen uptake during maximal upright exercise are poorlycharacterized and may differ in sinus rhythm and atrial fibrillation.Seventy patients with isolated mitral stenosis underwent Doppler-echocardiographyand bicycle exercise with respiratory gas analysis. Forty-twopatients were in sinus rhythm (Group I) and 28 in atrial fibrillation(Group II). Peak oxygen uptake it was 21·3±5·6ml. min^–1 kg^–1 in group I and 18·1 ±5·1 ml min^–1 kg^–1 in group II (P<0·05).There was no significant correlation between indices of exercisetolerance (exercise duration, ventilatory threshold, peak oxygenuptake, indexed peak oxygen uptake, peak oxygen pulse) and valvearea or gradient in either group. Indexed peak oxygen uptakewas not correlated to oxygen pulse but was linearly related(r=0·43) to heart rate ( heart rate =peak heart rate=restheart rate) in Group I but not in Group II. Thus, in patientswith mitral stenosis, no correlation was found between the mitralvalve area or the gradient at rest and maximal upright exercisetolerance, suggesting that peripheral adaptation and, in sinusrhythm, chronotropic reserve, are important compensatory mechanisms.     

Cardiorespiratory and symptomatic variables during maximal and submaximal exercise in men with stable effort angina: a comparison of atenolol and celiprolol

Celiprolol is a novel beta₁ selective adrenoreceptor blockerwith partial beta₂ agonism and direct vasodilator activity.These ancillary properties may reduce symptomatic breathlessnessand fatigue and modify respiration during exercise. To testthis hypothesis 20 men with stable effort angina were enrolledin a double-blind crossover study to investigate the effectsof atenolol 100 mg once daily (A) and celiprolol 400 mg oncedaily (C) on cardiorespiratory and symptomatic variables duringmaximal and submaximal exercise. Total exercise time on a modifiedBruce protocol was similar on both treatments: C 12.5 min, A13.1 min. During steady state submaximal exercise at 60.75%(mean 68%) of maximum work capacity, minute ventilation (C 33.81min^–1, A 33.51 min^–1), oxygen uptake (C 14.6 ml.kg^–1.min^–1, A 151 ml. kg^–1. min^–1), respiratoryexchange ratio (C0.89, A 0.87), ratio of VEI VCO₂ (C33.6, A33.4), ratio of VEIVO₂ (C2.34, A 2.72), Borg perceived exertionscore (C 11.2, A 10.9) and visual analogue scores for breathlessness(C 29.5, A 25.9) and muscle fatigue (C 28.9, A 26.0) were allsimilar on both treatments. At maximal exercise capacity onthe modified Bruce protocol, minute ventilation (C 58.31 min^–1,A 60.41 min^–1), oxygen uptake (C 21.3 ml. kg^–1.min^–1, A 21.7ml. kg^–1.min^–1), respiratoryexchange ratio (C 1.02, A.1.05), ratio VEIVCO₂ (C 34.8, A 35.9),and ratio VEIVO₂ (C2.80, A 2.83) were also similar on both drugs.Over a 10 day period anginal attacks (C 10.1 ± 10.4,A 5.4 ± 5.9) and sublingual GTN use (C 5.9 ± 10.3,A 4.4 ± 9.8) were both more frequent on celiprolol. We conclude, that in comparison with atenolol, celiprolol didnot modify respiration during either steady state submaximalor maximal exercise and did not alleviate symptomatic breathlessnessand fatigue. However, symptomatic ischaemia was more frequentwith celiprolol.     

Exercise metabolism during 1 hour of treadmill walking while taking high and low doses of propranolol,metoprolol, or placebo

Aerobic exercise and beta-blocking drugs are regularly prescribed as treatment for hypertension and as a prophylactic for patients at risk from coronary heart disease and for those recovering from an infarct. Some beta blockers, particularly non-beta₁-selective drugs, may make exercise more difficult, possibly by interfering with substrate metabolism during exercise. This study examined the effects of low and high doses of a beta₁-selective blocker, metoprolol, and a nonselective beta blocker, propranolol, on exercise metabolism. The study involved 20 healthy subjects (10 men, 10 women) who walked on a treadmill at 50% of their maximal oxygen uptake for 1 h on five occasions, separated by 7 days. On each of the five occasions they received one of the following treatments, given in random order: placebo, metoprolol 50 mg, metoprolol 100 mg, propranolol 40 mg, or propranolol 80 mg, all taken twice daily. Fat oxidation, expressed as a percentage of total energy expenditure, was significantly lower than with placebo for all of the active treatments except metoprolol 50 mg (placebo: 42.7 ± 11.6%; metoprolol 50 mg: 38.7 ± 14.1%, p = NS; metoprolol 100 mg: 36.3 ± 13.7%, p = 0.05; propranolol 40 mg: 31.2 ± 9.3%, p = 0.01; propranolol 80 mg: 29.5 ± 10.9%, p = 0.01); and significantly lower with propranolol than with metoprolol (propranolol 40 mg: p = 0.0036; propranolol 80 mg: p = 0.01). Plasma ammonia concentration was significantly higher than with placebo with propranolol 40 mg, propranolol 80 mg, and metoprolol 100 mg (p = 0.01 for all); with metoprolol 50 mg, there was no difference from placebo (p = NS). Both beta blockers in this study reduced fat metabolism and increased perceived exertion to some degree. Additional inhibition of fat oxidation occurred with the nonselective drug, probably in intramuscular rather than adipose lipolysis, and was probably beta₂ mediated. The results of this study suggest that a selective beta blocker has less of an adverse effect on substrate metabolism than does a nonselective beta blocker. Beta₁-selective drugs may offer advantages in patients who undertake regular aerobic exercise.     

Influence of body fat distribution on oxygen uptake and pulmonary performance in morbidly obese females during exercise

OBJECTIVE: The aim of this study was to determine the effects of fat distribution on aerobic and ventilatory response to exercise testing in morbidly obese (MO) females. METHODOLOGY: The study population consisted of 164 MO females, 55% (n = 90) with upper body or abdominal adiposity (UBD), as defined by waist-hip circumference ratio (WHR) > or = 0.80, and 45% (n = 74) with lower body fat distribution (LBD) (WHR < 0.80). An incremental exercise testing on cycle ergometer was performed to determine the effect of exercise on oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), tidal volume (VT), respiratory rate (fb) and heart rate (HR). RESULTS: Upper body adiposity individuals had significantly higher VO2 and VCO2 than LBD subjects (P < 0.05) from 0 watt (W) of pedalling up to their anaerobic threshold (AT) and maximal exercise. VE was significantly higher in UBD subjects compared with LBD subjects, from 20 W during exercise up to AT and peak work levels (P < 0.05). Upper body adiposity group also had a significantly higher fb than the LBD group at rest, after each workload and at AT and peak exercise work rates (P < 0.05). VT was lower in UBD subjects at free pedalling and up to AT and peak workload with significant difference at 60 and 80 W (P < 0.05). The anaerobic threshold, expressed as work rate, was significantly lower in the UBD subjects (P < 0.05) and peak workload achieved did not differ significantly between the two groups. CONCLUSIONS: Upper body adiposity subjects had higher oxygen requirement, more rapid and shallow breathing, higher ventilatory demand, but lower anaerobic threshold than the LBD individuals during progressive exercise. It suggests that the cardiopulmonary endurance to exercise in MO patients with upper body fat distribution is lower than in those with lower body fat distribution.     

Moderate-intensity exercise with blood flow restriction on cardiopulmonary kinetics and efficiency during a subsequent high-intensity exercise in young women: A cross-sectional study

Blood flow restriction (BFR) training applied prior to a subsequent exercise has been used as a method to induce changes in oxygen uptake pulmonary kinetics (V˙O_2P) and exercise performance. However, the effects of a moderate-intensity training associated with BFR on a subsequent high-intensity exercise on V˙O_2P and cardiac output (Q_T) kinetics, exercise tolerance, and efficiency remain unknown.This prospective physiologic study was performed at the Exercise Physiology Lab, University of Brasilia. Ten healthy females (mean ± SD values: age = 21.3 ± 2.2 years; height = 1.6 ± 0.07 m, and weight = 55.6 ± 8.8 kg) underwent moderate-intensity training associated with or without BFR for 6 minutes prior to a maximal high-intensity exercise bout. V˙O_2P, heart rate, and Q_T kinetics and gross efficiency were obtained during the high-intensity constant workload exercise test.No differences were observed in V˙O_2P, heart rate, and Q_T kinetics in the subsequent high-intensity exercise following BFR training. However, exercise tolerance and gross efficiency were significantly greater after BFR (220 ± 45 vs 136 ± 30 seconds; P < .05, and 32.8 ± 6.3 vs 27.1 ± 5.4%; P < .05, respectively), which also resulted in lower oxygen cost (1382 ± 227 vs 1695 ± 305 mL min^–1).We concluded that moderate-intensity BFR training implemented prior to a high-intensity protocol did not accelerate subsequent V˙O_2P and Q_T kinetics, but it has the potential to improve both exercise tolerance and work efficiency at high workloads.