Effects of graduated compression stockings on blood lactate following an exhaustive bout of exercise

To determine the effects of wearing graduated compression stockings (GCS) on the exercise response, twelve high fit males served as subjects in a series of two experiments. The first experiment consisted of six subjects performing two tests of maximal oxygen consumption (VO2 max) on a treadmill with and without GCS. The second experiment consisted of six subjects performing three separate three minute tests on a bicycle ergometer at 110% of their VO2 max. The experimental conditions for the three tests were: GCS worn during the test and recovery (GCS), GCS worn only during the test (GCS-O/O) and no stockings worn during either the test or recovery (NO-GCS). Oxygen consumption (VO2) was measured at rest, throughout the duration of all tests and during recovery in both experiments. Blood samples were obtained at rest and at 5, 15, 30, 45 and 60 minutes post exercise in the first experiment and at rest and at 5, 15 and 30 minutes post exercise in the second experiment for the determination of lactate and hematocrit. The use of GCS in the first experiment resulted in no significant difference in VO2 max, recovery VO2 or plasma volume shifts. Lactate values were lower throughout the duration of the recovery period with the 15 minute values being significantly different with the use of GCS. Significant differences in post exercise blood lactate values were found in the second experiment. The GCS trial resulted in significantly less lactate when compared to the GCS-O/O and the NO-GCS trials. There was no significant difference in post exercise lactate values between the NO-GCS and the GCS-O/O trials. Plasma volume changes were not significantly different among trials. Results of both experiments showed recovery lactate values to be lower with the use of GCS. These lower values are not ascribable to plasma volume shifts but rather appear to be due to an inverse gradient created by the GCS resulting in the lactate being retained in the muscular bed.     

Maximal oxygen consumption and pulmonary circulation in patients with chronic bronchitis

In order to study the relations between maximal oxygen consumption during exercise (VO2max) and the pulmonary circulation when pulmonary artery pressure (PPA) and pulmonary vascular resistance (PVR) are normal or close to normal, we evaluated twenty-three patients with chronic bronchitis, in stable clinical condition. All these patients performed a progressive exercise test on a bicycle ergometer until exhaustion (VO2max); they were also subjected to right heart catheterization at rest and during light exercise at constant load. In these patients with moderate functional impairment, we observed on average a significant, although weak, correlation (r = -0.52, P less than 0.01) between pulmonary vascular resistance at rest and VO2max. When VO2max exceeded 2 1 min-1, PVR was below 210 dyn s cm-5. From the heart rate during maximal exercise we computed the oxygen pulse (O2Pmax). In eight patients O2Pmax was reduced (less than or equal to 11 ml) with maximal heart rate close to its predicted value; in seven of these subjects PVR was abnormal and Ppa at rest was at least 20 mmHg. Thus it seems that in chronic obstructive bronchitis mild disturbances in pulmonary circulation may be a contributory factor in the limitation of exercise performance, and a maximal exercise test may help to detect pulmonary hypertension in these patients.     

Assessment of exercise capacity in women with type 2 diabetes

The primary aim of this study was to compare the maximal oxygen uptake as evaluated from a submaximal exercise test (EVO2peak) to direct measurements of VO2peak during a maximal exercise test as means of monitoring the aerobic endurance capacity in women with type 2 diabetes (T2D). Twenty-seven women with T2D participated in the study. The program consisted of combined group training 1 h twice a week during 12 weeks and walks 1 h per week. EVO2 max was estimated using a submaximal exercise test on a bicycle ergometer ad modum Astrand. VO2peak and maximal work rate were measured using an incremental maximal exercise test on an electrically braked bicycle ergometer at baseline and after 6 and 12 weeks. EVO2peak was higher than VO2peak at baseline and significantly higher at 12 weeks (EVO2peak1.92+/-0.54 l min(-1), VO2peak 1.41+/-0.36, P<0.005). Maximal work rate increased significantly after 12 weeks (12+/-15, P<0.005) compared to baseline. The main finding of this study was that EVO2peak assessed using a submaximal exercise test, systematically overestimated VO2peak. The combined group training increased maximal work rate but not VO2peak. This is likely to reflect peripheral adaptation to exercise and/or improved mechanical efficiency.     

负荷运动对能量代谢的影响及研究

目的探讨渐增负荷最大运动后的过量氧耗与血乳酸、血糖及氨基酸代谢的变化关系。方法受试者为10名男子健康大学生。采用活动跑台方法进行渐增负荷跑至力竭为止。结果运动结束30min,吸氧量恢复到安静水平时,血乳酸浓度仍比安静时水平高,运动中丙氨酸上升,运动结束30min丙氨酸减少,但并未恢复到安静时的水平。结论过量氧耗除用于血乳酸的消耗外,可能生要用于丙氨酸代谢中的糖新生。     

Growth hormone secretion in acid-base alterations at rest and during exercise.

1. Seven healthy males were studied during cycle ergometer exercise at 33%, 66% and 90% of VO2 max. on three occasions when NH4C1, NaHCO3 or CaCO3 (as a control substance) were administered in gelatin capsules double blind and in randomized order. Plasma growth hormone (HGH), lactic acid and hydrogen ion concentration ([H+]) were measured at frequent intervals. 2. Ammonium chloride produced highest blood [H+] and NaHCO3 the lowest. These differences were maintained during exercise and in recovery. Plasma lactic acid concentrations were similar at rest. At 66%, 90% VO2 max. and recovery lactic acid was highest with NaHCO3 and lowest with NH4C1. 3. Exercise stimulated HGH secretion in all studies and the elevation was proportional to the intensity of the exercise. NH4C1 caused a variable elevation of HGH at rest and 33% VO2 max. At 66% VO2 max., plasma HGH was significantly elevated to similar concentrations in all studies and, at 90% VO2 max., HGH was highest with NaHCO3. 4. An infusion of sodium L(+)-lactate producing plasma lactate concentrations of 3-5 mmol/l did not influence HGH secretion. 5. Exercise is a physiological stimulus to HGH secretion and the mechanism is independent of blood [H+] and lactate concentrations.     

The effect of interval training combined with thigh cuffs pressure on maximal and submaximal exercise performance

The purpose of the study was to investigate the effect of interval training combined with a thigh cuffs pressure of +90 mmHg on maximal and submaximal cycling performance. Twenty untrained individuals were assigned either to a control (CON) or to an experimental (CUFF) training group. Both groups trained 3 days per week for 6 weeks at the same relative intensity; each training session consisted of 2-min work bout at 90% of VO(2max): 2-min active recovery bout at 50% of VO(2max). An incremental exercise test to exhaustion, a 6-min constant-power test at 80% of VO(2max) (Sub(80)) and a maximal constant-power test to exhaustion (TF(150)) were performed pre- and post-training. Despite the unchanged VO(2max), both groups significantly increased peak power output (CON: ～12%, CUFF: ～20%) that was accompanied by higher deoxygenation (ΔStO(2)) measured with near-infrared muscle spectroscopy. These changes were more pronounced in the CUFF group. Moreover, both groups reduced VO(2) during the Sub(80) test without concomitant changes in ΔStO(2). TF(150) was enhanced in both groups. Thus, an interval exercise training protocol under moderate restricted blood flow conditions does not provide any additive effect on maximal and submaximal cycling performance. However, it seems to induce peripheral muscular adaptations, despite the lower absolute training intensity.     

Six weeks of aerobic dance exercise improves blood oxidative stress status and increases interleukin-2 in previously sedentary women

This study evaluated the change in blood oxidative stress, blood interleukin-2, and physical performance following 6 weeks of moderate intensity and duration aerobic dance exercise in 24 sedentary women. Blood samples were collected at rest twice before (baseline) and after the 6-week intervention for analysis of protein hydroperoxide (PrOOH), malondialdehyde (MDA), total anti-oxidant capacity (TAC), and interleukin-2 (IL-2) levels. Maximal treadmill run time (Time(max)) and maximal oxygen consumption (VO(2max)) were also measured. All variables were statistically analyzed with a repeated measurement ANOVA and Tukey post hoc. No differences were noted in any variable during the baseline period (p > 0.05). After aerobic dance exercise, VO(2max), Time(max), TAC and IL-2 were significantly increased, whereas MDA levels were decreased significantly (p < 0.05). PrOOH did not change either between baseline measures or after exercise. It can be concluded that aerobic dance exercise at a moderate intensity and duration can improve physical fitness, decrease MDA, and increase TAC and IL-2 in previously sedentary women.     

Deficiency of skeletal muscle succinate dehydrogenase and aconitase. Pathophysiology of exercise in a novel human muscle oxidative defect.

We evaluated a 22-yr-old Swedish man with lifelong exercise intolerance marked by premature exertional muscle fatigue, dyspnea, and cardiac palpitations with superimposed episodes lasting days to weeks of increased muscle fatigability and weakness associated with painful muscle swelling and pigmenturia. Cycle exercise testing revealed low maximal oxygen uptake (12 ml/min per kg; healthy sedentary men = 39 +/- 5) with exaggerated increases in venous lactate and pyruvate in relation to oxygen uptake (VO2) but low lactate/pyruvate ratios in maximal exercise. The severe oxidative limitation was characterized by impaired muscle oxygen extraction indicated by subnormal systemic arteriovenous oxygen difference (a-v O2 diff) in maximal exercise (patient = 4.0 ml/dl, normal men = 16.7 +/- 2.1) despite normal oxygen carrying capacity and Hgb-O2 P50. In contrast maximal oxygen delivery (cardiac output, Q) was high compared to sedentary healthy men (Qmax, patient = 303 ml/min per kg, normal men 238 +/- 36) and the slope of increase in Q relative to VO2 (i.e., delta Q/delta VO2) from rest to exercise was exaggerated (delta Q/delta VO2, patient = 29, normal men = 4.7 +/- 0.6) indicating uncoupling of the normal approximately 1:1 relationship between oxygen delivery and utilization in dynamic exercise. Studies of isolated skeletal muscle mitochondria in our patient revealed markedly impaired succinate oxidation with normal glutamate oxidation implying a metabolic defect at the level of complex II of the mitochondrial respiratory chain. A defect in Complex II in skeletal muscle was confirmed by the finding of deficiency of succinate dehydrogenase as determined histochemically and biochemically. Immunoblot analysis showed low amounts of the 30-kD (iron-sulfur) and 13.5-kD proteins with near normal levels of the 70-kD protein of complex II. Deficiency of succinate dehydrogenase was associated with decreased levels of mitochondrial aconitase assessed enzymatically and immunologically whereas activities of other tricarboxylic acid cycle enzymes were increased compared to normal subjects. The exercise findings are consistent with the hypothesis that this defect impairs muscle oxidative metabolism by limiting the rate of NADH production by the tricarboxylic acid cycle.     

田径运动员最大摄氧量和无氧功测试中血乳酸的应用

目的:研究田径运动员最大摄氧量和Wingate测试后血乳酸的变化,分析血乳酸对测试结果的意义。方法:测试田径短跑运动员36例和中长跑运动员29例的最大摄氧量和Wingate无氧功,以及测试后的血乳酸值。结果:最大摄氧量测试后血乳酸数值为9～11mmol/L左右,摄氧量与乳酸值没有直接相关关系,但不同项目之间有一定的差异;Wingate测试后血乳酸数值一般大于12mmol/L,测试的主要评价指标与乳酸值都有较高的相关关系。结论:血乳酸值对于最大摄氧量测试意义不大,但对于Wingate测试可以作为一项辅助评价指标。     

Submaximal exercise in persons with stroke: test-retest reliability and concurrent validity with maximal oxygen consumption

OBJECTIVE: To establish the test-retest reliability and concurrent validity with maximum oxygen consumption (VO2max) for 3 submaximal exercise tests in persons with chronic stroke: (1) submaximal treadmill test, (2) submaximal cycle ergometer test, and (3) 6-minute walk test (6MWT). DESIGN: Prospective study using a convenience sample. SETTING: Free-standing tertiary rehabilitation center. PARTICIPANTS: A volunteer sample of 12 community-dwelling individuals who had a stroke with moderate motor deficits. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Heart rate, blood pressure, and oxygen consumption (VO2) were assessed during the exercise tests. RESULTS: Test-retest reliability was good to excellent for the exercise tests (maximal and submaximal tests). VO2 for all submaximal measures related to VO2max (r range, .66-.80). Neither the 6MWT distance, self-selected gait speed, nor hemodynamic measures related to VO2max. CONCLUSION: The VO2 measures of the submaximal exercise tests had excellent reliability and good concurrent validity with VO2max. Submaximal exercise tests may be a method by which to monitor the effects of interventions after a screening test (eg, symptom-limited graded exercise test, dobutamine stress echocardiograph).     

六分钟步行试验与摄氧量的相关性研究

背景:6 min步行试验是一种亚极量水平的运动试验,其操作简便、费用低廉,因而应用较广泛,然而将步行距离转换为最大运动能力是不易的.目的:课题组创新性地在6 min步行实验中引入做功的概念,将无线遥测呼吸气体分析仪同时应用于6 min步行试验和心肺运动试验,分析6 min步行试验中的距离、做功与峰值摄氧量与Bruce方案测得的最大摄氧量之间的相关性.设计、时间及地点:实验于2009-03/05在南京东南大学附属中大医院康复医学科完成.对象:健康受试者来自在中大医院康复医学科实习的学生,共25名,男14名,女11名;年龄(22.0±2.3)岁.方法:25名志愿者先按Bruce方案进行极量心肺运动试验,检测每位受试者极量运动时的最大摄氧量和无氧阈,再接受6 min步行试验,测量每位受试者的6 min步行距离、做功和峰值摄氧量.心肺运动试验和6 min步行试验均采用便携式K4b~2气体分析仪实时检测气体交换参数,以获得最大摄氧量和峰值摄氧量.主要观察指标:①摄氧量、心率、呼吸频率随时间的变化规律.②步行距离、做功、摄氧量、心率、呼吸频率的前后比较.③心肺运动试验中的最大摄氧量、无氧阈与6 min步行试验中的峰值摄氧量比较.④距离、做功与峰值摄氧量、最大摄氧量之间的相关性.结果:心肺运动试验测得的无氧阈与6 min步行试验测得的峰值摄氧量之间差异无显著性意义(P > 0.05).6 min步行距离与峰值摄氧量和最大摄氧量均无明显相关;6 min步行做功与峰值摄氧量呈线性相关(r=0.779 7,P < 0.001);6 min步行做功与最大摄氧量亦呈线性相关(r=0.894 1,P < 0.001).结论:6 min步行试验是一种无氧阈水平的运动试验.6 min步行做功既可反映受试者亚极量运动的能力,也能反映受试者极量运动的能力.     

运动训练对低肺功能肺癌患者手术耐受性的影响

目的:探讨术前短期中高强度下肢运动训练对低肺功能肺癌患者肺切除手术耐受性的影响.方法:采用随机单盲设计,将61例可切除肺癌合并重度慢性阻塞性肺病患者,根据美国胸科医师协会肺切除术前评估指南分为可手术A组和不可手术B组;A组再随机分为A1亚组(训练亚组)和A2亚组(对照组).A1亚组和B组术前予每周5次、连续2周、强度达60％-80％峰值氧摄量VO2max的踏车运动训练,辅以胸腹联合缩唇呼吸训练.比较训练前后静态肺功能和运动心肺功能的变化;训练后重新评估B组手术风险;比较训练Al亚组和对照A2组肺切除术后并发症情况.结果:训练后,在A1亚组,心肺功能指标:肺一氧化碳弥散量DLCO(P=0.003)、VO2max(P＜0.001)、无氧阈AT(P=0.008)、氧脉VO2max/HR(P＜0.001)较训练前显著改善;在B组,心肺功能指标:用力肺活量FVC(P＜0.001)、分钟最大通气量MVV (P=0.001)、DL.CO (P＜0.001)、最大功率W(P=0.004)、VO2max (P＜0.001)、AT(P=0.002)、VO2max/HR (P=0.00l)、峰值通气量VEmax(P=0.015)、无氧阈时CO2通气当量VE/VCO2@AT (P=0.003)和运动后经皮血氧饱和度SPO2％(P=0.002)均较训练前显著改善;B组中59％(10/17)患者达手术标准;训练A1亚组较对照A2组,肺切除术后氧疗时间(P=0.04)、机械通气时间(P=0.036)和住院天数(P=0.025)均显著缩短.结论:术前短期中高强度下肢运动训练能有效、可行地提高低肺功能肺癌患者心肺功能适应性,有助于肺切除术后康复.     

Pacemaker implantation as a risk factor for heart failure in young adults with congenital heart disease

AIM: Complete postoperative heart block following open-heart surgery and sinus node dysfunction are indications for permanent cardiac pacing in children with congenital heart defects. The purpose of our study was to evaluate if cardiac pacing is a risk factor of heart failure during longtime follow-up of grown ups with congenital heart disease (GUCH). METHODS: For an objective assessment of heart failure, NT-Pro brain natriuretic peptide (BNP) and maximal oxygen uptake index (VO2max) during the cardiopulmonary exercise testing were measured in 346 consecutive GUCH patients during a longtime follow-up examination. RESULTS: Thirty-nine of these patients who had pacemaker implantation had significantly increased BNP levels (448.2 +/- 76.8 vs 123.8 +/- 9.7 pg/mL, P < 0.0001) and significantly decreased VO(2max) (22.5 +/- 0.9 vs 27.4 +/- 0.4, P < 0.0001). Heart failure in pacemaker patients was associated with significantly prolonged QRS complex durations (171.1 +/- 8.3 ms vs 108.7 +/- 1.8 ms, P < 0.0001), increased right ventricular end diastolic diameters (38.7 +/- 2.1 mm vs 27.8 +/- 0.5mm, P < 0.0001), lower heart rates at rest (69.5 +/- 1.9/min vs 82 +/- 1/min, P < 0.0001), and at exercise (140.3 +/- 5.8/min vs 163.5 +/- 1.2/min, P < 0.0001). Mean fractional shortening of the left ventricle was normal in both patient groups. CONCLUSION: Pacemaker implantation may be associated with heart failure during longtime follow-up of GUCH indicated by significantly elevated BNP levels and decreased VO2max. Possible explanations are prolongation of QRS complex duration, decreased maximal heart rates during exercise, and dilatation of the right ventricle.     

Maximal oxygen consumption in patients with lung disease.

A theoretical model for oxygen transport assuming a series linkage of ventilation, diffusion, oxygen uptake by erythrocytes, cardiac output, and oxygen release was used to calculate expected values for maximal oxygen intake (VO2max) of patients with various pulmonary disorders 22 patients with either restrictive or obstructive ventilatory impairment were studied at rest and maximal exercise. When exercise measurements of maximal pulmonary blood flow (QCmax), oxygen capacity, membrane diffusing capacity for CO, pulmonary capillary blood volume, alveolar ventilation, and mixed venous oxygen saturation were employed as input values, predictions of VO2max from the model correlated closely with measured values (r = 0.978). Measured VO2max was 976+/-389 ml/min (45.3+/-13% of predicted normal), and VO2max predicted from the model was 1,111+/-427 ml/min. The discrepancy may in part reflect uneven matching of alveolar ventilation, pulmonary capillary blood flow, and membrane diffusing capacity for CO within the lung; uniform matching is assumed in the model so that mismatching will impair gas exchange beyond our predictions. Although QCmax was less than predicted in most patients (63.6+/-19.6% of predicted) the model suggests that raising QCmax to normal could have raised VO2max only 11.6+/-8.8% in the face of existent impairment of intrapulmonary gas exchange. Since pulmonary functions measured at rest correlated well with exercise parameters needed in the model to predict VO2max we developed a nomogram for predicting VO2max from resting CO diffusing capacity, the forced one second expired volume, and the resting ratio of dead space to tidal volume. The correlation coefficient between measured and predicted VO2max, by using this nomogram, was 0.942.     

Growth hormone response in very short children.

Growth hormone (GH) response to standardized exercise, L-DOPA/propranolol and a 6-h diurnal GH profile (GHP) were evaluated in twenty-three children with very short stature and abnormal growth velocities. Standardized exercise (Jones Stage I) was performed on a cycle ergometer at 53% of the maximum oxygen consumption (VO2max) for 20 min. VO2max was determined by an incremental progressive workload until exhaustion. The mean +/- SEM peak GH concentration (ng/ml) for each test was: exercise, 8.7 +/- 1.3; L-DOPA/P: 12.8 +/- 1.9 and GHP: 3 +/- 0.7. There was no statistical difference between exercise and L-DOPA/P peaks but both peaks were significantly higher than the peak observed during the profile. During exercise 14 of 23 patients had a GH response greater than 8 ng/ml. Two patients were found to be GH deficient. Therefore 16 of 23 patients (86%) had a result concordant with their final diagnosis. During the L-DOPA/P test 17 of 23 patients had a GH response greater than 8 ng/ml. By contrast only 6 of 23 patients had a positive response during GHP. Standardized exercise is as effective as L-DOPA/P as a stimulation test for growth hormone response in very short children with abnormal growth velocities. Exercise has the advantages of being physiological, having minimal side effects, and requiring fewer blood samples. In this population of children, exercise and L-DOPA/propranolol are significantly better than the 6-h growth hormone profile for assessing GH secretion.     

Blood hormone and metabolite levels during graded cycle ergometer exercise

To study the effect of the intensity of physical exercise on plasma hormone and metabolite levels, a group of 11 well-conditioned males participated in cycle ergometer exercise. The subjects pedalled at three different work loads, corresponding to 63% of VO2max (duration 10 min), 86% of VO2max (duration 10 min) and maximal work load (tolerated 5-7 min) The increases in blood adrenaline, noradrenaline, growth hormone, cyclic AMP, glycerol and lactate concentrations were remarkably similar and exponentially related to the work load. The concentrations of blood glucose, cortisol and glucagon increased only at maximal work load. Many of these changes in blood metabolite and hormone concentrations seem to be related to the increased sympathetic activity during graded exercise.     

Maximal short term exercise capacity in healthy subjects aged 15-70 years

Fifty males and 50 females, 15-71 years of age, exercised maximally for 30 s on an isokinetic ergometer at a pedalling frequency of 60 rev./min. Results were compared with maximal oxygen uptake (VO2 max.) obtained in a progressive incremental exercise test. Total work in 30 s was higher in males than females, declined linearly by about 6% per decade of age (r = -0.65), and was related closely to height (r = 0.75) and to lean thigh volume estimated anthropometrically (r = 0.84). A close association with vital capacity (r = 0.86) was also found that accounted statistically for the combined effects of age and height. The percentage decline in power during 30 s (fatigue index) was lower in subjects reporting greater leisure activity. A close relationship was found between total work in 30 s and VO2max. (r = 0.86), with vital capacity and leisure activity exerting additional influences on VO2max. (P less than 0.001; multiple r = 0.93). The well-established reduction with age in VO2max. is associated with an apparent parallel reduction in the power output capacity of large muscle groups recruited in heavy dynamic leg exercise.     

Detection of lactate threshold by including haemodynamic and oxygen extraction data

To date, few attempts have been made to correlate cardiovascular variables to lactate threshold (L(T)). This study was designed to determine the relationship between the accumulation of blood lactate and several haemodynamic variables during exercise. Eight male volunteer cyclists performed an incremental test on an electromagnetically braked cycle-ergometer consisting of a 50 W linear increase in workload every 3 min up to exhaustion. Blood lactate was measured with a portable analyser during each exercise step. Oxygen consumption (VO(2)) and pulmonary ventilation were measured by means of a mass spectrometer while heart rate, stroke volume and cardiac output (CO) were assessed by impedance cardiography. The arterio-venous oxygen difference (A-V O(2) Diff) was obtained by dividing VO(2) by CO. By applying the D(max) mathematical method, L(T) and thresholds of ventilatory and haemodynamic parameters were calculated. The Bland and Altman statistics used to assess agreement between two methods of measurement were applied in order to evaluate the agreement between L(T) and thresholds derived from ventilatory and haemodynamic data. The main result was that most of the haemodynamic variables did not provide thresholds which could be used interchangeably with L(T). Only the threshold of A-V O(2) Diff showed mean values that were no different compared to L(T) together with limits of agreement that were not very wide between thresholds (below +/-25%). Hence of the haemodynamic parameters, A-V O(2) Diff appears to be the one most closely coupled with lactate accumulation and consequently it is also the most suitable for non-invasive calculation of the L(T).     

Height-adjusted, rate-specific, single-stage step test for predicting maximal oxygen consumption

A suitable ergometer that is generally favored for estimating maximal oxygen consumption (VO2 max) under field conditions or in environments where testing equipment is limited is the step test. Recently a mathematical model was reported to standardize the height of stepping for individuals of various heights. We designed a study to validate this model using a three-minute single-stage step test for predicting VO2 max in women. Seventeen women aged 19 to 33 performed each of three rate-specific step tests and a Bruce treadmill test. Direct measurements of VO2 max obtained from the treadmill test were correlated with the 15 second recovery heart rates after three different step tests done at stepping frequencies of 22, 26, and 30 step-ups per minute. The correlation coefficients of prediction of VO2 max from 15 second recovery pulse counts and directly measured oxygen consumption were 0.74 at 22 step-ups/min, 0.77 at 30 step-ups/min, and 0.8 at 26 step-ups/min. Each relationship was significant at the P less than .01 level. It can be concluded that the single-stage step test described in this study provides an effective predictor of VO2 max in young women and can be used when more complex methods of laboratory testing are unavailable or not feasible.