Estimating stroke volume from oxygen pulse during exercise

Crisafulli, Antonio; Piras, Francesco; Chiappori, Paolo; Vitelli, Stefano; Caría, M. A.; Lobina, Andrea; Milia, Raffaele; Tocco, Filippo; Concu, Alberto; Melis, Franco

doi:10.1088/0967-3334/28/10/006

Cited by 62 publications

(50 citation statements)

References 40 publications

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“…Previous studies have identified a correlation between stroke volume and O 2 pulse during exercise in humans (23,24). increased with increasing Htc values in both groups (Fig.…”

Section: Effect Of Varying Blood Volume Total Hemoglobin Mass Andmentioning

confidence: 55%

Optimal hematocrit for maximal exercise performance in acute and chronic erythropoietin-treated mice

Schuler

Arras

Keller

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

101

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Erythropoietin (Epo) treatment increases hematocrit (Htc) and, consequently, arterial O 2 content. This in turn improves exercise performance. However, because elevated blood viscosity associated with increasing Htc levels may limit cardiac performance, it was suggested that the highest attainable Htc may not necessarily be associated with the highest attainable exercise capacity. To test the proposed hypothesis that an optimal Htc in acute and chronic Epotreated mice exists-i.e., the Htc that facilitates the greatest O 2 flux during maximal exercise-Htc levels of wild-type mice were acutely elevated by administering novel erythropoiesis-stimulating protein (NESP; wtNESP). Furthermore, in the transgenic mouse line tg6 that reaches Htc levels of up to 0.9 because of constitutive overexpression of human Epo, the Htc was gradually reduced by application of the hemolysis-inducing compound phenylhydrazine (PHZ; tg6PHZ). Maximal cardiovascular performance was measured by using telemetry in all exercising mice. Highest maximal O 2 uptake ( _ VO 2max ) and maximal time to exhaustion at submaximal exercise intensities were reached at Htc values of 0.58 and 0.57 for wtNESP, and 0.68 and 0.66 for tg6PHZ, respectively. Rate pressure product, and thus also maximal working capacity of the heart, increased with elevated Htc values. Blood viscosity correlated with _ VO 2max . Apart from the confirmation of the Htc hypothesis, we conclude that tg6PHZ adapted better to varying Htc values than wtNESP because of the higher optimal Htc of tg6PHZ compared to wtNESP. Of note, blood viscosity plays a critical role in limiting exercise capacity.blood viscosity | doping | excessive erythrocytosis | exercise performance | hemolysis

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“…Previous studies have identified a correlation between stroke volume and O 2 pulse during exercise in humans (23,24). increased with increasing Htc values in both groups (Fig.…”

Section: Effect Of Varying Blood Volume Total Hemoglobin Mass Andmentioning

confidence: 55%

Optimal hematocrit for maximal exercise performance in acute and chronic erythropoietin-treated mice

Schuler

Arras

Keller

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

101

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“…Oxygen pulse, a non-invasive marker of stroke volume [12][13][14], was calculated from V9O 2 and cardiac frequency (eC) collected breath-by-breath during the CPET as previously described [22].…”

Section: Oxygen Pulsementioning

confidence: 99%

“…We hypothesised that LVRS would lead to an increase in non-invasive markers of stroke volume (oxygen pulse [12][13][14] and pulse pressure (PP) [15,16]) during exercise and that these improvements would correlate with a reduction in DH.…”

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confidence: 99%

Increased oxygen pulse after lung volume reduction surgery is associated with reduced dynamic hyperinflation

et al. 2012

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Stroke volume augmentation during exercise is limited in chronic obstructive pulmonary disease patients because of decreased preload from dynamic hyperinflation (DH). We hypothesised that oxygen pulse and pulse pressure (PP) improve following lung volume reduction surgery (LVRS), and the magnitude of improvement correlates with reduction in DH.We compared 16 emphysema patients undergoing LVRS with six emphysema patients not undergoing LVRS. Oxygen pulse and PP were calculated from maximal cardiopulmonary exercise tests at baseline and 6 months. End-expiratory lung volume (EELV)/total lung capacity (TLC) represented DH. Comparisons were made between baseline and 6 months at metabolic isotimes (per cent maximal carbon dioxide production (V9CO 2 ,max)).At baseline, the LVRS group was older with higher forced expiratory volume in 1 s, but had similar hyperinflation to the non-LVRS group. At 6 months, oxygen pulse (50%, 75%, and 100% V9CO 2 ,max) and PP (50% and 75% V9CO 2 ,max) increased in the LVRS, but not in the non-LVRS group. Baseline functional residual capacity/TLC inversely correlated with resting oxygen pulse (r5 -0.449, p50.04). Decreased EELV/TLC correlated with increased oxygen pulse at 75% (r5 -0.487, p50.02) and 100% V9CO 2 ,max (r5 -0.548, p50.008).LVRS led to increased oxygen pulse and PP during exercise at metabolic isotimes 6 months following surgery. Reductions in DH correlated with increases in oxygen pulse during exercise. Reducing lung volume may improve stroke volume response to exercise by decreasing DH.KEYWORDS: Cardiopulmonary interactions, chronic obstructive pulmonary disease, exercise, physiology C hronic obstructive pulmonary disease (COPD) patients have impaired exercise tolerance, which limits their quality of life. While ventilatory limitations, including dynamic hyperinflation (DH), are the main cause of exercise intolerance in this population [1], causes for this impairment are probably multifactorial [2]. Impairment in cardiac mechanics in COPD may be one of the most important contributing factors. Stroke volume is reduced in COPD, especially during exercise [3]. Decreased stroke volume is due to increased intrathoracic pressures and decreased cardiac right-sided filling [4][5][6].Along with its beneficial effects on mortality [7] and pulmonary function [8], lung volume reduction surgery (LVRS) improves exercise capacity by altering lung mechanics [7,9,10]. LVRS also favourably affects stroke volume, both at rest [8] and during exercise [11]. Increased right ventricular stroke volume post-LVRS has been reported to correlate with decreased resting hyperinflation [11]. The effect of DH on cardiac function during exercise in COPD, however, is unknown.To investigate the effect of DH and LVRS on cardiac performance during exercise, we retrospectively analysed data from emphysema patients who had cardiopulmonary exercise tests (CPETs) before and after LVRS, and compared their changes with those who did not undergo LVRS. We hypothesised that LVRS would lead to an increase in no...

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“…Thus, different investigators using distinct populations and/or clinical and sports settings have proposed that the O 2 pulse can indirectly reflect stroke volume, so that both the maximum value and the curve shape, which are a function of CPET duration, will be directly associated with cardiac inotropism and lusitropism (4)(5)(6)(7)(8)(9)(10). In this context, several studies have shown that relatively low maximum O 2 pulse values are associated with a lower survival rate among middle-aged individuals as well as patients with heart failure (11,12), most likely reflecting impaired inotropic and/or lusitropic capacity and then disturbing the stroke volume response to exercise.…”

mentioning

confidence: 99%

Stability of relative oxygen pulse curve during repeated maximal cardiopulmonary testing in professional soccer players

Perim¹,

Signorelli²,

Araújo³

2011

Braz J Med Biol Res

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During cardiopulmonary exercise testing (CPET), stroke volume can be indirectly assessed by O2 pulse profile. However, for a valid interpretation, the stability of this variable over time should be known. The objective was to analyze the stability of the O2 pulse curve relative to body mass in elite athletes. VO2, heart rate (HR), and relative O2 pulse were compared at every 10% of the running time in two maximal CPETs, from 2005 to 2010, of 49 soccer players. Maximal values of VO2 (63.4 ± 0.9 vs 63.5 ± 0.9 mL O2•kg-1•min-1), HR (190 ± 1 vs188 ± 1 bpm) and relative O2 pulse (32.9 ± 0.6 vs 32.6 ± 0.6 mL O2•beat-1•kg-1) were similar for the two CPETs (P > 0.05), while the final treadmill velocity increased from 18.5 ± 0.9 to 18.9 ± 1.0 km/h (P < 0.01). Relative O2 pulse increased linearly and similarly in both evaluations (r² = 0.64 and 0.63) up to 90% of the running time. Between 90 and 100% of the running time, the values were less stable, with up to 50% of the players showing a tendency to a plateau in the relative O2 pulse. In young healthy men in good to excellent aerobic condition, the morphology of the relative O2 pulse curve is consistent up to close to the peak effort for a CPET repeated within a 1-year period. No increase in relative O2pulse at peak effort could represent a physiologic stroke volume limitation in these athletes

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Estimating stroke volume from oxygen pulse during exercise

Cited by 62 publications

References 40 publications

Optimal hematocrit for maximal exercise performance in acute and chronic erythropoietin-treated mice

Optimal hematocrit for maximal exercise performance in acute and chronic erythropoietin-treated mice

Increased oxygen pulse after lung volume reduction surgery is associated with reduced dynamic hyperinflation

Stability of relative oxygen pulse curve during repeated maximal cardiopulmonary testing in professional soccer players

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