Ventilatory Control Dynamics During Muscular Exercise in Man

Whipp, Brian J.; Ward, Susan A.

doi:10.1055/s-2008-1034653

Cited by 39 publications

(11 citation statements)

References 76 publications

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“…We also have to take variations in lactacid buffer capacity in our subjects into account which may influence the response of cardio-respiratory system to incremental exercise (36). This capacity is related to muscle fiber composition, being higher in subjects with a greater number of fast twitch (FT) fibers (31).…”

Section: Discussionmentioning

confidence: 99%

Relationship Between Heart Rate Threshold, Lactate Turn Point and Myocardial Function

et al. 1994

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We examined the relationship between heart rate threshold (HRT), lactate turn point (LTP) and myocardial function expressed as left ventricular ejection fraction (LVEF) determined by radionuclide ventriculography. Two groups of subjects (G I: N = 8; G II: N = 7) with and without a deflection of heart rate performance curve (HRPC) underwent sitting cycle ergometry. HRT (G I), aerobic threshold (AeT; G I, G II), and LTP (G I, G II) were determined by means of linear regression break point analysis. Also, a break point in LVEF performance curve (LVEFBP) was obtained. Power output at HRT and at LTP was not significantly different between G I and G II (272.5 +/- 38.7 W; 294.3 +/- 20.6 W). Power output at LVEFBP (G I: 182.6 +/- 31.7 W; G II: 211.8 +/- 21.5 W) was not significantly different to power output at LTP (G I: 194.2 +/- 32.7 W; G II: 215.2 +/- 24.4 W) and HRT (G I: 193.0 +/- 38.2 W). Significant differences (p < 0.05) could only be found between G I and G II for heart rate (HR) at LTP (G I: 163.5 +/- 5.8 b.min-1; G II: 154.4 +/- 6.7 b.min-1) and LVEF at the end of the load (LVEFend) (G I: 77.9 +/- 2.9%; G II: 71.3 +/- 7.0%). The drop of LVEF at LVEFBP was significantly related to LTP in all cases. The present data suggest that the noninvasive determination of anaerobic threshold by means of heart rate curve analysis is not always possible due to different response of myocardial function and heart rate to graded cycle ergometer exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 99%

Relationship Between Heart Rate Threshold, Lactate Turn Point and Myocardial Function

et al. 1994

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“…9 13.3k2.1 r=0.97 (p<0.01) The estimation of the anaerobicventilatory threshold (AT) was performed by analysis of the behaviour ofVC02 versusV02 following the V-Slope method of Beaver 141. The respiratory compensation point (RCP) was defined as the deflection point in the time course of end-tidal C0,-concentration (C02-ET), plotting C02-ETagainst running speed [41]. Both calculations were supported using a PC-routine.…”

Section: Respiratory Analysismentioning

confidence: 99%

Ventilatory, Lactate-Derived and Catecholamine Thresholds During Incremental Treadmill Running: Relationship and Reproducibility

Dickhuth¹,

Yin²,

Niess³

et al. 1999

Int J Sports Med

142

140

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Anaerobic threshold as a basic criterion of training recommendation can be estimated by various parameters. The purpose of this study was to investigate the relationship and the reproducibility of ventilatory, lactate-derived and catecholamine thresholds of an incremental treadmill exercise. Therefore, 11 male subjects underwent two incremental treadmill tests within 7 days. The lactate threshold (LT) was determined at the lowest value of the lactate-equivalent (ratio lactate/performance). The individual anaerobic threshold (IAT) was calculated at LT+1.5 mmol/L lactate. The ventilatory thresholds, using mass-spectrometry, were defined by the V-slope method (AT) and at the deflection point of end-tidal CO2 (ET-CO2) concentration (RCP). The thresholds of epinephrine (TE) and norepinephrine (TNE) were calculated in the manner of LT. The running velocities were highly reproducible at LT (test-retest correlation coefficient r=0.90), IAT (r=0.97), AT (r=0.88) and RCP (r=0.95). By contrast TE (r=0.49) and TNE (r=0.46) showed a poor reproducibility. TE and TNE occurred 5-11% below LT and AT with a low correlation to LT and AT. LT was found 4% below AT, both were correlated with r=0.70 (p<0.01, test 1) and r=0.95 (p<0.01, test 2). IAT occurred 7-8% above RCP, in both tests a close correlation was found between IAT and RCP of r=0.97 (p<0.01). In summary, the ventilatory and lactate-derived thresholds show a high and similar reproducibility, but the catecholamine threshold does not. In the present exercise protocol, there are systematic differences between the lactate-derived and ventilatory thresholds, in spite of a close relationship, and these must be taken into account in recommendations derived for training.

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“…This lactic acidosis produces an exponential rise in V e, which is usually accompanied by a decrease in Paco 2 . 69,70 The second ventilatory threshold is a second nonlinear increase in ventilation that occurs when the subject reaches 70 to 90% of their maximal V o 2 . At this point, ventilation increases disproportionately to both V o 2 and CO 2 elimination.…”

Section: Exercisementioning

confidence: 99%

The Control of Breathing in Clinical Practice

Caruana-Montaldo¹,

Gleeson

Zwillich

2000

Chest

130

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The control of breathing results from a complex interaction involving the respiratory centers, which feed signals to a central control mechanism that, in turn, provides output to the effector muscles. In this review, we describe the individual elements of this system, and what is known about their function in man. We outline clinically relevant aspects of the integration of human ventilatory control system, and describe altered function in response to special circumstances, disorders, and medications. We emphasize the clinical relevance of this topic by employing case presentations of active patients from our practice.(CHEST 2000; 117:205-225)Key words: carotid body; chemoreceptors; control of ventilation; pulmonary receptors Abbreviations: CPAP ϭ continuous positive airway pressure; CSF ϭ cerebrospinal fluid; CSR ϭ Cheyne-Stokes respiration; DRG ϭ dorsal respiratory group; [H ϩ ] ϭ hydrogen ion concentration; HCO 3 Ϫ ϭ bicarbonate; MVV ϭ maximal voluntary ventilation; OSA ϭ obstructive sleep apnea; pHa ϭ arterial pH; PIIA ϭ postinspiration inspiratory activity; PImax ϭ maximal inspiratory pressure; RAR ϭ rapidly adapting receptor; REM ϭ rapid eye movement; Sao 2 ϭ arterial oxygen saturation; SAR ϭ slowly adapting receptor; VC ϭ vital capacity; V e ϭ minute ventilation; V o 2 ϭ oxygen uptake; V /Q ϭ ventilation/perfusion; VRG ϭ ventral respiratory group; Vt ϭ tidal volume; WOB ϭ work of breathing

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Ventilatory Control Dynamics During Muscular Exercise in Man

Cited by 39 publications

References 76 publications

Relationship Between Heart Rate Threshold, Lactate Turn Point and Myocardial Function

Relationship Between Heart Rate Threshold, Lactate Turn Point and Myocardial Function

Ventilatory, Lactate-Derived and Catecholamine Thresholds During Incremental Treadmill Running: Relationship and Reproducibility

The Control of Breathing in Clinical Practice

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