Cardiac output with modified cardio-impedance against inert gas rebreathing during sub-maximal and maximal cycling exercise in healthy and fit subjects

Torto, Alessio Del; Skattebo, Øyvind; Hallén, Jostein; Capelli, Carlo

doi:10.1007/s00421-018-4011-z

Cited by 5 publications

(8 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, they concluded they could not be used interchangeably because of the great disparity in results at rest and in low-to-moderate intensity exercises. Unlike this study, Torto et al 15 showed that cardio-impedance could be less ideal for supramaximal exercise intensities.…”

contrasting

confidence: 54%

Continuous Non-Invasive Cardiac Output: Myth or Reality

Neto

2019

Arquivos Brasileiros De Cardiologia

View full text Add to dashboard Cite

contrasting

confidence: 54%

Continuous Non-Invasive Cardiac Output: Myth or Reality

Neto

2019

Arquivos Brasileiros De Cardiologia

View full text Add to dashboard Cite

“…One proposed explanation for the measurement error is the recirculation of nitrous oxide into the pulmonary system during the rebreathing procedure (36). However, the reproducibility and reliability of the method have shown good results (33,50). Nevertheless, one should be cautious when interpreting the absolute values generated by the method, especially if one is attempting to derive other physiological parameters from the existing data on Qmax .…”

Section: Discussionmentioning

confidence: 99%

Improvements in Maximal Oxygen Uptake After Sprint-Interval Training Coincide with Increases in Central Hemodynamic Factors

Mandić

Hansson

Lovrić

et al. 2022

Medicine &Amp; Science in Sports &Amp; Exercise

View full text Add to dashboard Cite

IntroductionSprint-interval training has been shown to improve maximal oxygen uptake, in part through peripheral muscle adaptations that increase oxygen utilization. In contrast, the adaptations of central hemodynamic factors in this context remain unexplored.PurposeThe aim of the current study was to explore the effects of sprint-interval training on maximal oxygen uptake and central hemodynamic factors.MethodsHealthy men and women (n = 29; mean age, 27 ± 5 yr; height, 175 ± 8 cm; body mass, 72.5 ± 12.0 kg) performed 6 wk of sprint-interval training consisting of three weekly sessions of 10-min low-intensity cycling interspersed with 3 × 30-s all-out sprints. Maximal oxygen uptake, total blood volume, and maximal cardiac output were measured before and after the intervention.ResultsMaximal oxygen uptake increased by 10.3% (P < 0.001). Simultaneously, plasma volume, blood volume, total hemoglobin mass, and cardiac output increased by 8.1% (276 ± 234 mL; P < 0.001), 6.8% (382 ± 325 mL; P < 0.001), 5.7% (42 ± 41 g; P < 0.001), and 8.5% (1.0 ± 0.9 L·min−1; P < 0.001), respectively. Increased total hemoglobin mass along with measures of body surface area had a significant impact on the improvements in maximal oxygen uptake.ConclusionsSix weeks of sprint-interval training results in significant increases in hemoglobin mass, blood volume, and cardiac output. Because these changes were associated with marked improvements in maximal oxygen uptake, we conclude that central hemodynamic adaptations contribute to the improvement in maximal oxygen uptake during sprint-interval training.

show abstract

“…But the main finding was that the ET-induced increase in V O 2peak was preserved despite removing the increase in Hb mass , and this conclusion is based on methods with low typical error ( V O 2peak 2.9% and Hb mass 1.1%). Impedance cardiography is associated with a larger measurement error than the invasive gold-standard methods (Del Torto et al 2019;Richard et al 2001). Besides, when calculating the a-v O 2 diff from V O 2 and Q inherent of its measurements errors, a larger measurement error is expected as compared with deriving a-vO 2 diff using arterial and venous blood sampling.…”

Section: Study Considerationsmentioning

confidence: 99%

Blood volume expansion does not explain the increase in peak oxygen uptake induced by 10 weeks of endurance training

et al. 2020

Self Cite

View full text Add to dashboard Cite

Purpose The endurance training (ET)-induced increases in peak oxygen uptake (V O 2peak) and cardiac output (Q peak) during upright cycling are reversed to pre-ET levels after removing the training-induced increase in blood volume (BV). We hypothesised that ET-induced improvements in V O 2peak and Q peak are preserved following phlebotomy of the BV gained with ET during supine but not during upright cycling. Arteriovenous O 2 difference (a-vO 2 diff; V O 2 /Q), cardiac dimensions and muscle morphology were studied to assess their role for the V O 2peak improvement. Methods Twelve untrained subjects (V O 2peak : 44 ± 6 ml kg −1 min −1) completed 10 weeks of supervised ET (3 sessions/ week). Echocardiography, muscle biopsies, haemoglobin mass (Hb mass) and BV were assessed pre-and post-ET. V O 2peak and Q peak during upright and supine cycling were measured pre-ET, post-ET and immediately after Hb mass was reversed to the individual pre-ET level by phlebotomy. Results ET increased the Hb mass (3.3 ± 2.9%; P = 0.005), BV (3.7 ± 5.6%; P = 0.044) and V O 2peak during upright and supine cycling (11 ± 6% and 10 ± 8%, respectively; P ≤ 0.003). After phlebotomy, improvements in V O 2peak compared with pre-ET were preserved in both postures (11 ± 4% and 11 ± 9%; P ≤ 0.005), as was Q peak (9 ± 14% and 9 ± 10%; P ≤ 0.081). The increased Q peak and a-vO 2 diff accounted for 70% and 30% of the V O 2peak improvements, respectively. Markers of mitochondrial density (CS and COX-IV; P ≤ 0.007) and left ventricular mass (P = 0.027) increased. Conclusion The ET-induced increase in V O 2peak was preserved despite removing the increases in Hb mass and BV by phlebotomy, independent of posture. V O 2peak increased primarily through elevated Q peak but also through a widened a-vO 2 diff, potentially mediated by cardiac remodelling and mitochondrial biogenesis. Keywords Blood volume • Cardiac output • Echocardiography • Haemoglobin mass • Maximal oxygen uptake • Peripheral adaptations • Supine cycling Abbreviations a-vO 2 diff Arteriovenous oxygen difference BV Blood volume CO Carbon monoxide COX-IV Cytochrome c oxidase subunit 4 CS Citrate synthase EDV End-diastolic volume ESV End-systolic volume ET Endurance training HAD Hydroxyacyl-CoA dehydrogenase [Hb] Haemoglobin concentration Hb mass Haemoglobin mass HR Heart rate HR peak Peak heart rate [La] Blood lactate concentration LV Left ventricle MCHC Mean corpuscular haemoglobin concentration MTT Mean transit time PV Plasma volumė Q Cardiac outpuṫ Q peak Peak cardiac output Communicated by Peter Krustrup.

show abstract

Cardiac output with modified cardio-impedance against inert gas rebreathing during sub-maximal and maximal cycling exercise in healthy and fit subjects

Cited by 5 publications

References 19 publications

Continuous Non-Invasive Cardiac Output: Myth or Reality

Continuous Non-Invasive Cardiac Output: Myth or Reality

Improvements in Maximal Oxygen Uptake After Sprint-Interval Training Coincide with Increases in Central Hemodynamic Factors

Blood volume expansion does not explain the increase in peak oxygen uptake induced by 10 weeks of endurance training

Contact Info

Product

Resources

About