Maximal Cardiorespiratory Responses Research Articles

Short-Term Effect of Bariatric Surgery on Cardiorespiratory Response at Submaximal, Ventilatory Threshold, and Maximal Exercise in Women with Severe Obesity.

People with obesity have varying degrees of cardiovascular, pulmonary, and musculoskeletal dysfunction that affect aerobic exercise testing variables. Short time after bariatric surgery, these dysfunctions could affect both peak oxygen consumption ([Formula: see text] O2 peak), the gold standard for assessing cardiorespiratory fitness (CRF) and aerobic capacity evaluated with ventilatory threshold (VT1). The purpose of this study was to evaluate the short-term effect of bariatric surgery, i.e. before the resumption of physical activity, on submaximal, at VT1 and maximal cardiorespiratory responses in middle-aged women with severe obesity. Thirteen middle-aged women with severe obesity (age: 36.7 ± 2.3years; weight: 110.5 ± 3.6kg, BMI: 41.8 ± 1.1kg/m2) awaiting bariatric surgery participated in the study. Four weeks before and 6 to 8weeks after surgery, body composition was determined by bioelectrical impedance. The participants performed an incremental cycling test to [Formula: see text] O2 peak. After bariatric surgery, all body composition parameters were reduced, absolute [Formula: see text] O2 peak and peak workload decline with a lower VT1. Relative [Formula: see text] O2 at peak and at VT1 (ml/min/kg or ml/min/kg of FFM) remained unchanged. Ventilation was lower after bariatric surgery during exercise with no change in cardiac response. Our results showed that weight loss alone at short-term after bariatric surgery decreased CRF as seen by a decrease in absolute [Formula: see text] O2 peak, and peak workload with lower VT1, whereas relative [Formula: see text] O2 (ml/min/kg or ml/min/kg of FFM) during exercise remained unchanged in women with obesity. Rapid FFM loss affects cardiorespiratory responses at submaximal and maximal.

Kingfish (Seriola lalandi) adjust to low salinity with only subtle effects to cardiorespiratory and growth performance

At reduced salinities nearing isosmotic conditions, marine fishes experience reduced osmotic gradients between body fluids and the surrounding water, which should lower energetic costs of osmoregulation. Such energy savings on osmoregulation can potentially be directed to other processes such as growth, suggesting the possibility that rearing euryhaline fishes under reduced salinity in aquaculture may be a beneficial practice. The yellowtail kingfish (Seriola lalandi) is one such aquaculture species that appears to benefit from low salinity, as juveniles display faster growth when reared at salinities approaching isosmotic conditions. Here, we tested the hypothesis that, due to reduced osmoregulatory costs, growth is improved in sub-adult kingfish reared at low salinity, and this is associated with a down-regulation of resting cardiorespiratory activity reflecting energetic savings. Furthermore, to gain a more complete picture of how low salinity impacts cardiorespiratory function in kingfish, we also assessed maximal cardiorespiratory responses to enforced exercise. Two experiments were carried out. The first assessed resting and maximum cardiac and respiratory performance of kingfish acclimated to seawater (35 ppt), and after ~20 h (acute) or > 4 weeks (chronic) exposure to brackish water (17 ppt). Acute 17 ppt exposure reduced standard metabolic rate (i.e. resting O2 consumption rate; 179.4 mg O2∙h−1∙kg−1) relative to fish maintained in seawater (198.3 mg O2∙h−1∙kg−1), but this difference was no longer apparent following chronic acclimation to 17 ppt (191.3 mg O2∙h−1∙kg−1). While maximum metabolic rate was not affected by salinity, kingfish both acutely transferred and acclimated to 17 ppt had a reduced excess post-exercise O2 consumption compared to fish in 35 ppt. Acclimation to 17 ppt was also associated with a reduced proportion of ventricle compact myocardium. In a second experiment, we analyzed growth rate and feed conversion efficiency of kingfish acclimated to seawater (35 ppt) or brackish water (24 and 12 ppt) for 8 weeks. Contrary to our initial hypothesis, growth rate and feed conversion efficiency were slightly deteriorated (by ~5 and ~ 6% for growth rate and feed conversion efficiency, respectively) after 4 weeks acclimation to 12 ppt; however, these differences were no longer apparent after 8 weeks acclimation. This study shows neither substantial benefits nor costs of brackish water exposure to cardiorespiratory and growth performance in sub-adult kingfish, suggesting this species can be reared at salinities as low as 12 ppt.

A Focused Review on the Maximal Exercise Responses in Hypo- and Normobaric Hypoxia: Divergent Oxygen Uptake and Ventilation Responses.

The literature suggests that acute hypobaric (HH) and normobaric (NH) hypoxia exposure elicits different physiological responses. Only limited information is available on whether maximal cardiorespiratory exercise test outcomes, performed on either the treadmill or the cycle ergometer, are affected differently by NH and HH. A focused literature review was performed to identify relevant studies reporting cardiorespiratory responses in well-trained male athletes (individuals with a maximal oxygen uptake, VO2max > 50 mL/min/kg at sea level) to cycling or treadmill running in simulated acute HH or NH. Twenty-one studies were selected. The exercise tests in these studies were performed in HH (n = 90) or NH (n = 151) conditions, on a bicycle ergometer (n = 178) or on a treadmill (n = 63). Altitudes (simulated and terrestrial) varied between 2182 and 5400 m. Analyses (based on weighted group means) revealed that the decline in VO2max per 1000 m gain in altitude was more pronounced in acute NH vs. HH (−7.0 ± 1.4% vs. −5.6 ± 0.9%). Maximal minute ventilation (VEmax) increased in acute HH but decreased in NH with increasing simulated altitude (+1.9 ± 0.9% vs. −1.4 ± 1.8% per 1000 m gain in altitude). Treadmill running in HH caused larger decreases in arterial oxygen saturation and heart rate than ergometer cycling in acute HH, which was not the case in NH. These results indicate distinct differences between maximal cardiorespiratory responses to cycling and treadmill running in acute NH or HH. Such differences should be considered when interpreting exercise test results and/or monitoring athletic training.

Are heart rate dynamics in the transition from rest to submaximal exercise related to maximal cardiorespiratory responses in COPD?

BackgroundPoor exercise capacity is an important negative prognostic marker in patients with chronic obstructive pulmonary disease (COPD). Heart rate variability (HRV) responses can indicate alterations in cardiac autonomic control. Nevertheless, it remains unclear whether these abnormalities are related to cardiorespiratory responses to exercise in these patients. ObjectiveTo evaluate whether HRV at rest and submaximal exercise are related to impaired cardiopulmonary responses to exercise in COPD patients. MethodsFifteen men (66.2±8.7 years) with COPD (FEV1: 55.1±19.2%) were assessed. The R-R interval (RRi) data collection was performed at rest (stand position) and during the six-minute walk test (6MWT). All patients performed a symptom-limited cardiopulmonary exercise test on a cycle ergometer. The HRV changes from rest to submaximal exercise (Δ rest-6MWT) were calculated. ResultsWe found significant correlations between low frequency (LF) and high frequency (HF) Δ rest-6MWT with Δ oxyhemoglobin saturation by pulse oximetry (r=−0.64 and r=0.65, respectively; p<0.05), minute ventilation/carbon dioxide output relationship from beginning to peak exercise (r=−0.52 and r=0.53, p<0.05), and exercise ventilatory power (r=0.52 and r=−0.53, p<0.05). Interestingly, there was a strong positive correlation (r=0.82, p<0.05) between six-minute walk distance (6MWD) and Δ LF/HF from rest to exercise. ConclusionHRV analysis in the transition from rest to submaximal exercise is associated with exercise ventilatory and hemodynamic abnormalities in COPD patients. Rehabilitative strategies to improve HRV responses may provide an important tool to clinical practice in these patients.

High intensity interval training (HIIT) improves resting blood pressure, metabolic (MET) capacity and heart rate reserve without compromising cardiac function in sedentary aging men.

This study examined a programme of pre-conditioning exercise with subsequent high intensity interval training (HIIT) on blood pressure, echocardiography, cardiac strain mechanics and maximal metabolic (MET) capacity in sedentary (SED) aging men compared with age matched masters athletes (LEX). Using a STROBE compliant observational design, 39 aging male participants (SED; n=22, aged 62.7±5.2yrs) (LEX; n=17, aged=61.1±5.4yrs) were recruited to a study that necessitated three distinct assessment phases; enrolment (Phase A), following pre-conditioning exercise in SED (Phase B), then following 6weeks of HIIT performed once every five days by both groups before reassessment (Phase C). Hemodynamic, echocardiographic and cardiac strain mechanics were obtained at rest and maximal cardiorespiratory and chronotropic responses were obtained at each measurement phase. The training intervention improved systolic, mean arterial blood pressure, rate pressure product and heart rate reserve (each P<0.05) in SED and increased MET capacity in both SED and LEX (P<0.01) which was amplified by HIIT. Echocardiography and cardiac strain measures were unremarkable apart from trivial increase to intra-ventricular septum diastole (IVSd) (P<0.05) and decrease to left ventricular internal dimension diastole (LVId) (P<0.05) in LEX following HIIT. A programme of preconditioning exercise with HIIT induces clinically relevant improvements in blood pressure, rate pressure product and encourages recovery of heart rate reserve in SED, while improving maximal MET capacity in both SED and LEX without inducing any pathological cardiovascular remodeling. These data add to the emerging repute of HIIT as a safe and promising exercise prescription to improve cardiovascular function and metabolic capacity in sedentary aging.

Does HRV During Submaximal Exercise Transitions From Rest Relate To Maximal Cardiorespiratory Responses In COPD?

Does HRV During Submaximal Exercise Transitions From Rest Relate To Maximal Cardiorespiratory Responses In COPD?

Cardiorespiratory responses and prediction of peak oxygen uptake during the shuttle walking test in healthy sedentary adult men.

BackgroundThe application of the Shuttle Walking Test (SWT) to assess cardiorespiratory fitness and the intensity of this test in healthy participants has rarely been studied. This study aimed to assess and correlate the cardiorespiratory responses of the SWT with the cardiopulmonary exercise testing (CEPT) and to develop a regression equation for the prediction of peak oxygen uptake (VO2 peak) in healthy sedentary adult men.MethodsIn the first stage of this study, 12 participants underwent the SWT and the CEPT on a treadmill. In the second stage, 53 participants underwent the SWT twice. In both phases, the VO2 peak, respiratory exchange ratio (R), and heart rate (HR) were evaluated.ResultsSimilar results in VO2 peak (P>0.05), R peak (P>0.05) and predicted maximum HR (P>0.05) were obtained between the SWT and CEPT. Both tests showed strong and significant correlations of VO2 peak (r = 0.704, P = 0.01) and R peak (r = 0.737, P<0.01), as well as the agreement of these measurements by Bland-Altman analysis. Body mass index and gait speed were the variables that explained 40.6% (R2 = 0.406, P = 0.001) of the variance in VO2 peak. The results obtained by the equation were compared with the values obtained by the gas analyzer and no significant difference between them (P>0.05) was found.ConclusionsThe SWT produced maximal cardiorespiratory responses comparable to the CEPT, and the developed equation showed viability for the prediction of VO2 peak in healthy sedentary men.

Effects of Obesity on Maximal Cardiorespiratory Fitness, Cardiovascular Responses, Fatigue, and Muscle Activation during Graded Exercise Test in Female Sports Aerobic Athletes

Effects of Obesity on Maximal Cardiorespiratory Fitness, Cardiovascular Responses, Fatigue, and Muscle Activation during Graded Exercise Test in Female Sports Aerobic Athletes

Cardiorespiratory Responses to the 30-15 Intermittent Ice Test

In this study, the authors compared the cardiorespiratory responses between the 30-15 Intermittent Ice Test (30-15(IIT)) and the 30-15 Intermittent Fitness Test (30-15(IFT)) in semiprofessional hockey players. Ten players (age 24 ± 6 y) from a Swiss League B team performed the 30-15(IIT) and 30-15(IFT) in random order (13 ± 4 d between trials). Cardiorespiratory variables were measured with a portable gas analyzer. Ventilatory threshold (VT), respiratory-compensation point (RCP), and maximal speeds were measured for both tests. Peak blood lactate ([La(peak)]) was measured at 1 min postexercise. Compared with 30-15(IFT), 30-15(IIT) peak heart rate (HR(peak); mean ± SD 185 ± 7 vs 189 ± 10 beats/min, P = .02) and peak oxygen consumption (VO(2peak)); 60 ± 7 vs 62.7 ± 4 mL/min/kg, P = .02) were lower, whereas [La(peak)] was higher (10.9 ± 1 vs 8.6 ± 2 mmol/L, P < .01) for the 30-15(IIT). VT and RCP values during the 30-15(IIT) and 30-15(IFT) were similar for %HR(peak) (76.3% ± 5% vs 75.5% ± 3%, P = .53, and 90.6% ± 3% vs. 89.8% ± 3%, P = .45) and % VO(2peak) (62.3% ± 5% vs 64.2% ± 6%, P = .46, and 85.9% ± 5% vs 84.0% ± 7%, P = .33). VO(2peak ))(r = .93, P < .001), HR(peak) (r = .86, P = .001), and final velocities (r = .69, P = .029) were all largely to almost perfectly correlated. Despite slightly lower maximal cardiorespiratory responses than in the field-running version of the test, the on-ice 30-15(IIT) is of practical interest since it is a specific maximal test with a higher anaerobic component.

Maximal Cardiorespiratory Responses During Acute Exposure to 4300 M; Challenging Previous Research Using a Multi-Study Database

Maximal oxygen uptake (VO2max) decreases ∼ 27% during an acute (< 24 h) exposure to 4300 m in direct relation to the decline in arterial oxygen saturation at maximal effort (SaO2max). However, previous research suggests that maximal heart rate (HRmax) and pulmonary ventilation (VEmax) are not changed from sea level (SL) during an acute exposure to 4300 m (Reeves, 2002; Wolfel and Levine, 2001) and thus unlikely to contribute to the decline in VO2max. PURPOSE: Investigate possible relationships between the change in VO2max, SaO2max, HRmax, and VEmax from SL during an acute (< 24 h) exposure to 4300 m altitude (AA) using an USARIEM database encompassing 7 studies from 1992 to 2004. METHODS: Data were retrospectively analyzed in 88 male lowlanders (27±5 yr, 76±11 kg; ±SD) that performed a VO2max test on a cycle ergometer or treadmill at SL and within 24-h exposure to either Pikes Peak (4300 m) or the hypobaric chamber (4300 m, 446 mmHg). At maximal effort, VO2max, SaO2max, HRmax, and VEmax were measured. Pearson-product correlations were calculated for the relationships between the change in VO2max, SaO2max, HRmax, and VEmax from SL to AA. RESULTS: From SL to AA, there was a 27% decrease(P=0.0001) in VO2max (4.0±0.7 to 2.9±0.5 1·min-1) and SaO2max(96±2 to 71±8%), a 5% decrease (P=0.0001) in HRmax (186±10 to 177±10 beats·min−1), and 6% increase (P=0.0001) in VEmax (BTPS) (146±30 to 155±33 1·min−1). The change in VO2max was correlated with change in SaO2max (r=0.29; p=0.04) and VEmax (r=0.29, p=0.007) but not HRmax (r=0.07, p=0.62). CONCLUSIONS: These results confirm the ∼27% decrease in VO2max and SaO2max during an acute exposure to 4300 m. In contrast to previous research, there was a highly significant decrease in HRmax and increase in VEmax during maximal effort. It appears that lowlanders who demonstrate a greater increase in VEmax from SL to 4300 m also have less of a decline in VO2max from SL to 4300 m whereas the decline in HRmax had little impact on the decrement in VOmax.

Cardiorespiratory responses to physical work during and following 17 days of bed rest and spaceflight

To determine the influence of a 17-day exposure to real and simulated spaceflight (SF) on cardiorespiratory function during exercise, four male crewmembers of the STS-78 space shuttle flight and eight male volunteers were studied before, during, and after the 17-day mission and 17 days of -6 degrees head-down-tilt bed rest (BR), respectively. Measurements of oxygen uptake, pulmonary ventilation, and heart rate were made during submaximal cycling 60, 30, and 15 days before the SF liftoff and 12 and 7 days before BR; on SF days 2, 8, and 13 and on BR days 2, 8, and 13; and on days 1, 4, 5, and 8 after return to Earth and on days 3 and 7 after BR. During 15 days before liftoff, day 4 after return, and day 8 after return and all BR testing, each subject completed a continuous exercise test to volitional exhaustion on a semirecumbent (SF) or supine (BR) cycle ergometer to determine the submaximal and maximal cardiorespiratory responses to exercise. The remaining days of the SF testing were limited to a workload corresponding to 85% of the peak pre-SF peak oxygen uptake (Vo2 peak) workload. Exposure to and recovery from SF and BR induced similar responses to submaximal exercise at 150 W. Vo2 peak decreased by 10.4% from pre-SF (15 days before liftoff) to day 4 after return and 6.6% from pre-BR to day 3 after return, which was partially (SF: -5.2%) or fully (BR) restored within 1 wk of recovery. Workload corresponding to 85% of the peak pre-SF Vo2 peak showed a rapid and continued decline throughout the flight (SF day 2, -6.2%; SF day 8, -9.0%), reaching a nadir of -11.3% during testing on SF day 13. During BR, Vo2 peak also showed a decline from pre-BR (BR day 2, -7.3%; BR day 8, -7.1%; BR day 13, -9.0%). These results suggest that the onset of and recovery from real and simulated microgravity-induced cardiorespiratory deconditioning is relatively rapid, and head-down-tilt BR appears to be an appropriate model of this effect, both during and after SF.

Submaximal and Maximal Cardiorespiratory Responses of Leg Wheeling and Arm Wheeling a New Wheelchair Prototype

The present study examined the cardiorespiratory responses to propelling a new wheelchair prototype using a unique type of leg wheeling (LW) that allowed the subjects to propel the wheelchair using bilateral knee extension/flexion. Comparisons were made to arm wheeling (AW) and to treadmill running (TR) using a standard maximal oxygen consumption test to exhaustion. Nine female able-bodied subjects performed three incremental submaximal exercise bouts followed by exercise to exhaustion using AW and LW. The results showed that LW was more efficient than AW, as evidenced by lower cardiorespiratory effort at the same submaximal intensity during LW, and a lower physiological cost index (PCI—change in heart rate divided by velocity of wheeling) during maximal workloads. LW also elicited significantly higher peak cardiorespiratory values than AW but not TR. The cardiorespiratory variables measured during LW were also highly reliable. In conclusion, this unique form of LW was more efficient than AW during submaximal and maximal exercise.

Cardiorespiratory Responses of Trained Boys to Treadmill and Arm Ergometry: Effect of Training Specificity

The purpose of this study was to examine the maximal cardiorespiratory responses of trained adolescent male swimmers (SWM, N = 18), soccer players (SOC, N = 18), and moderately active reference subjects (CON, N = 16) to treadmill running (TRD) and arm ergometry (ARM). Mean values (±SD)for skeletal age were similar among the three groups (12.5± 1.9, 12.7 ± 1.1, and 12.5 ± 1.6 years, for the SWM, SOC, and CON, respectively). Allometric scaling procedures, relating VO2max and body mass, were used and mass exponents of .80 and .74 were identified for TRD and ARM data, respectively. During TRD testing SOC attained significantly higher VO2max values when expressed in ml · kg−1 · min−1, or ml · kg−0.80 · min−1 than the other two groups. However, during ARM testing, the SWM achieved significantly higher VO2peak values (ml · kg−0.74 · min−1 and scaled to arm-CSA) than SOC. The ratio of ARM-VAT to TRD-VAT was significantly higher in SWM (50.1± 9%) compared to SOC (41.2±5%), or CON (41.9 ± 6%).

TIME COURSE OF CARDIORESPIRATORY DECONDITIONING WITH 17 DAYS OF 6?? HEAD DOWN TILT BEDREST 866

The purpose of this project was to assess the time course of exercise cardiorespiratory changes in response to 17 days of 6° head down tilt bedrest. Seven males (age, 42.3 ±8.7 yr.; height, 181.4 ±6.5 cm; weight, 79.8 ±10.6) completed a continuous exercise test to volitional exhaustion on a supine cycling ergometer prior to bedrest (CON), on days 2 or 3 of bedrest (BR1), 8 or 9 (BR2), and 13 or 14 (BR3), as well as on days 3 or 4 of recovery (R1), and 7 or 8 (R2) to determine the submaximal (150 W) and maximal cardiorespiratory responses to exercise. Submaximal oxygen consumption(VO2) and minute ventilation (VE) did not change from CON during bedrest or recovery. Heart rate (HR: b·min-1) was significantly elevated (p<0.05) from CON (124±4) during BR2 (134±4), BR3(138±4), and R1 (135±2), but had returned to CON levels by R2(128±3). VO2max (L·min-1) was decreased(p<0.05) from CON (3.24±0.20) during BR1 (2.99±0.17; -7.3%), BR2 (3.00±0.17; -7.1%), BR3 (2.92±0.20; -9.0%), and R1(3.02±0.20; -6.6%), but was not different (p > 0.05) than CON by R2(3.13±0.19; -3.3%). HRmax did not change from CON during bedrest or recovery. Initial changes in VO2max (BR1) were significantly correlated with urine balance during bedrest day 1 (r=0.91, p < 0.05). These results suggest that the time course for changes in the cardiorespiratory responses to exercise are not linear and are related to the initial changes in body fluid volumes during 6° head down tilt bedrest.

Interactive effects of body posture and exercise training on maximal oxygen uptake

To determine the effect of posture on maximal O2 uptake (VO2 max) and other cardiorespiratory adaptations to exercise training, 16 male subjects were trained using high-intensity interval and prolonged continuous cycling in either the supine or upright posture 40 min/day 4 days/wk for 8 wk and 7 male subjects served as non-training controls. VO2 max measured during upright cycling and supine cycling, respectively, increased significantly (P less than 0.05) by 16.1 +/- 3.4 and 22.9 +/- 3.4% in the supine training group (STG) and by 14.6 +/- 2.0 and 6.0 +/- 2.0% in the upright training group (UTG). The increase in VO2 max measured during supine cycling was significantly greater (P less than 0.05) in the STG than in the UTG. The increase in VO2 max in the UTG was significantly greater (P less than 0.05) when measured during upright exercise than during supine exercise. However, there was no significant difference in posture-specific VO2 max adaptations in the STG. A postural specificity was also evident in other maximal cardiorespiratory variables (ventilation, CO2 production, and respiratory exchange ratio). In the UTG, maximal heart rate decreased significantly (P less than 0.05) only during supine cycling; there was no significant difference in maximal heart rate after training in the STG. We conclude that posture affects maximal cardiorespiratory adaptations to cycle training. Additionally, supine training is more effective than upright training in increasing maximal cardiorespiratory responses measured during supine exercise, and the effects of supine training generalize to the upright posture to a greater extent than the effects of upright training generalize to the supine posture.(ABSTRACT TRUNCATED AT 250 WORDS)

Stair climbing: An alternative exercise modality for firefighters : Ben-Ezra, V., and Verstraete, R.J Occup Med, 1988, 30.2, 103–105

The purpose of this investigation was to determine the maximal cardiorespiratory responses of firefighters to stair-climbing work and to compare these responses to maximal treadmill exercise. Thirty-eight firefighters volunteered to participate in the study. Maximal CR including oxygen consumption (VO2), ventilatory equivalent for oxygen (VE/VO2), minute ventilation (VE) and heart rate (HR) were measured during both stair climbing and graded treadmill exercise. The results showed that VO2max and HRmax were significantly lower, 7% and 2% respectively, and the VE/VO2 was significantly higher (6.7%) during the stair-climbing exercise. Maximal VE was not different between the two modes of exercise. The results suggest that since VO2max and HRmax were lower during stair climbing, the metabolic cost of firefighting tasks as related to VO2max on a treadmill may not be accurately reflected. Since stair climbing is a task-specific activity for firefighters, it is recommended that testing of firefighters be performed on a stair-climbing device, and that the difference in VO2max between treadmill and stair-climbing exercise be considered when recommending a desired fitness level for firefighters.

Maximal cardiorespiratory responses to one- and two-legged cycling during acute and long-term exposure to 4300 meters altitude

During exposure to altitudes greater than about 2200 m, maximal oxygen uptake (VO2max) is immediately diminished in proportion to the reduction in the partial pressure of oxygen in the inspired air. If the exposure lasts longer than a couple of days, an increase in arterial oxygen content (CaO2), due to a hemoconcentration and an increase in arterial oxygen saturation, occurs. However, there is also a reduction in maximal cardiac output (Qmax) at altitude which offsets the increase in CaO2 and, therefore, VO2max does not improve. The purpose of this investigation was to study the contribution of the increase in CaO2 to the working muscles without the potentially confounding problem of a reduced Qmax. The approach used was to have seven male subjects (aged 17 to 24 years) perform one- and two-legged VO2max tests on a cycle ergometer at sea level (SL, PIO2 = 159 Torr), after 1 h at 4300 m simulated altitude (SA, PIO2 = 94 Torr) and during two weeks of residence on the summit of Pikes Peak, CO. (PP, 4300 m, PIO2 = 94 Torr). Cardiac output limits maximal performance during two-legged cycling but does not limit performance during one-legged cycling. During the study, CaO2 changed from 189 +/- 3 (mean +/- SE) at SL to 161 +/- 4 ml.L-1 during SA (SL vs. SA, p less than 0.01) and to 200 +/- 6 ml.L-1 at PP (SL vs. PP, p less than 0.05; SA vs. PP, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

STAIR-CLIMBING

Research has shown that stair-climbing is an effective training modality for improving cardiorespiratory fitness. Little information, however, is available regarding the effectiveness of stair-climbing as a maximal exercise testing modality. The purpose of this investigation was to compare maximal cardiorespiratory (CR) responses between positive stair-climbing, using a unique step ergometer known as a Stair-Master (SM) and graded treadmill (TM) exercise. Thirty-eight fire-fighters (mean age 35.1 ± 1.6 years), volunteered for this study. Each subject was tested on the TM and SM on two separate days. During each maximal test, ventilated and expired gas was collected and analyzed for minute ventilation(±E), oxygen consumption (±O2), and the ventilatory equivalent of oxygen(±E/±O2). Heart rate was recorded each minute via 5 lead ECG. The TM test was a progressive protocol increasing speed or grade every two minutes. The SM protocol began with an initial step rate of approximately 55 per minute and thereafter the rate increased 8–10 steps every two minutes. The maximal CR responses were as follows: Stair-climbing appears to be a viable exercise testing modality which, although yielding lower maximal values than the treadmill (±02max, 7%; ±E, 3.5%; HR, 2%), it does yield higher maximal data than what has been reported for the bicycle ergometer. Stair-climbing using the StairMaster produces a typical HR/workload response and it therefore would be possible to establish an exercise prescription

Maximal cardiorespiratory responses of males and females to bicycle and treadmill ergometry

Maximal cardiorespiratory responses of males and females to bicycle and treadmill ergometry

Hemodynamic response to work with different muscle groups, sitting and supine.

Hemodynamic response to work with different muscle groups, sitting and supine.