Detection of the change point in oxygen uptake during an incremental exercise test using recursive residuals: relationship to the plasma lactate accumulation and blood acid base balance

1998 ◽  
Vol 78 (4) ◽  
pp. 369-377 ◽  
Author(s):  
Jerzy A. Zoladz ◽  
Zbigniew Szkutnik ◽  
Joanna Majerczak ◽  
Krzysztof Duda
Keyword(s):  
Oxygen Uptake ◽  
Exercise Test ◽  
Change Point ◽  
Incremental Exercise ◽  
Plasma Lactate ◽  
Acid Base Balance ◽  
Acid Base ◽  
Incremental Exercise Test ◽  
Base Balance ◽  
Recursive Residuals

Maximal oxygen uptake, ventilatory threshold and fat oxidation after an incremental exercise test in triathletes

2017 ◽  
Vol 176 (12) ◽  
Author(s):  
Hanapi M. Johari ◽  
Brinnell A. Caszo ◽  
Victor F. Knight ◽  
Steven A. Lumley ◽  
Aminuddin K. Abdul Hamid ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Exercise Test ◽  
Maximal Oxygen Uptake ◽  
Ventilatory Threshold ◽  
Fat Oxidation ◽  
Incremental Exercise ◽  
Incremental Exercise Test

Blood lactate and acid-base balance in graded neonatal hypoxia: evidence for oxygen-restricted metabolism

1994 ◽  
Vol 77 (5) ◽  
pp. 2318-2324 ◽  
Author(s):  
S. M. Torrance ◽  
C. Wittnich
Keyword(s):  
Lactic Acidosis ◽  
Oxygen Uptake ◽  
Anaerobic Metabolism ◽  
Base Excess ◽  
Severe Hypoxia ◽  
Oxygen Extraction ◽  
Acid Base Balance ◽  
Acid Base ◽  
Neonatal Response ◽  
Base Balance

This study examines the neonatal response to graded hypoxia and determines the arterial PO2 (PaO2) threshold for oxygen-restricted metabolism as confirmed by the development of lactic acidosis and altered oxygen handling. Anesthetized, intubated, and ventilated 3-day-old pigs (n = 56) were randomly assigned to one of five predetermined acute (120 min) graded hypoxia groups: normoxia (PaO2 = 80 Torr) or mild (60 Torr), moderate (40 Torr), moderately severe (30 Torr), or severe (20 Torr) hypoxia. In moderate hypoxia, lactate and acid-base homeostasis were unaltered due to a significant increase in oxygen extraction (P < 0.05) that was sufficient to maintain the arteriovenous oxygen content difference (oxygen uptake). In moderately severe hypoxia, increased arterial lactate and decreased HCO3- and base excess were evidence of anaerobic metabolism, yet pH was unaltered, indicating adequate buffering. In this group, despite the increase in oxygen extraction, oxygen uptake was reduced, indicating the onset of oxygen-restricted metabolism. The severe hypoxia group had significantly increased lactate (21.7 +/- 3.9 mmol/l), decreased pH (7.01 +/- 0.07) and base excess (-21.5 +/- 3.0 mmol/l), and depletion of HCO3- (9.7 +/- 1.6 mmol/l) (P < 0.0001). Here, increases in oxygen extraction were severely limited by availability, resulting in significantly reduced oxygen uptake, anaerobic metabolism, and profound lactic acidosis.

Acid-Base Balance with Different Capd Solutions

1996 ◽  
Vol 16 (1_suppl) ◽  
pp. 126-129 ◽  
Author(s):  
Mariano Feriani ◽  
Claudio Ronco ◽  
Giuseppe La Greca
Keyword(s):  
Acid Production ◽  
Dwell Time ◽  
Lactate Concentration ◽  
The Body ◽  
Plasma Lactate ◽  
Acid Base Balance ◽  
Bicarbonate Concentration ◽  
Acid Base ◽  
Plasma Bicarbonate ◽  
Base Balance

Our objective is to investigate transperitoneal buffer fluxes with solution containing lactate and bicarbonate, and to compare the final effect on body base balance of the two solutions. One hundred and four exchanges, using different dwell times, were performed in 52 stable continuous ambulatory peritoneal dialysis (CAPD) patients. Dialysate effluent lactate and bicarbonate and volumes were measured. Net dialytic base gain was calculated. Patients’ acid-base status and plasma lactate were determined. In lactate-buffered CAPD solution, lactate concentration in dialysate effluent inversely correlated with length of dwell time, but did not correlate with plasma lactate concentration and net ultrafiltration. Bicarbonate concentration in dialysate effluent correlated with plasma bicarbonate and dwell time but not with ultrafiltration. The arithmetic sum of the lactate gain and bicarbonate loss yielded the net dialytic base gain. Ultrafiltration was the most important factor affecting net dialytic base gain. A previous study demonstrated that in patients using a bicarbonate-buffered solution the net bicarbonate gain is a function of dwell time, ultrafiltration, and plasma bicarbonate. By combining the predicted data of the dialytic base gain with the calculated metabolic acid production, an approximate body base balance could be obtained with both lactate and bicarbonate-buffered CAPD solutions. The body base balance in CAPD patients is self-regulated by the feedback between plasma bicarbonate concentration and dialytic base gain. The level of plasma bicarbonate is determined by the dialytic base gain and the metabolic acid production. This can explain the large interpatient variability in acid-base correction. Bicarbonate-buffered CAPD solution is equal to lactate solution in correcting acid-base disorders of CAPD patients.

scholarly journals Effects of short‐term training on plasma acid‐base balance during incremental exercise in man

2003 ◽  
Vol 550 (2) ◽  
pp. 585-603 ◽  
Author(s):  
Charles T. Putman ◽  
Norman L. Jones ◽  
George J. F. Heigenhauser
Keyword(s):  
Incremental Exercise ◽  
Acid Base Balance ◽  
Acid Base ◽  
Short Term ◽  
Base Balance

Physiological Responses to Short-Duration High-Intensity Intermittent Rowing

1996 ◽  
Vol 21 (3) ◽  
pp. 197-208 ◽  
Author(s):  
Lennart Gullstrand
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Blood Lactate ◽  
Exercise Test ◽  
Intermittent Exercise ◽  
Lactate Concentration ◽  
Incremental Exercise ◽  
Competition Intensity ◽  
Incremental Exercise Test ◽  
Rowing Ergometer

Six highly trained male elite rowers performed five sets of intermittent exercise on a rowing ergometer at competition intensity. Each set consisted of eight cycles of 15 s work and 15 s rest (15/15). Each set was repeated at 30-s intervals. Oxygen uptake and heart rate were continuously measured during each set. During the period between sets, microsamples of arterialized blood were obtained and later analyzed for lactate concentration. On two separate days, each subject also performed a 6-min bout of "all-out " exercise and a continuous incremental exercise test to fatigue on the rowing ergometer. During the intermittent rowing, no significant differences were detected in any of the measured variables between sets. Heart rate, oxygen uptake, and blood lactate averaged 89, 78, and 32%, respectively, of peak values measured during the continuous incremental exercise test. It is concluded that with rowing, the investigated 15/15 intermittent exercise model demands relatively high aerobic loading and low glycolytic activity. This exercise protocol may be considered an alternative model for training which allows rowers to work for prolonged periods of time at or slightly above competition intensity. Key words: Intermittent exercise, blood lactate, heart rate, oxygen uptake

scholarly journals Comparison of the Ramp and Step Incremental Exercise Test Protocols in Assessing the Maximal Fat Oxidation Rate in Youth Cyclists

2021 ◽  
Vol 80 (1) ◽  
pp. 163-172
Author(s):  
Kamil Michalik ◽  
Natalia Danek ◽  
Marek Zatoń
Keyword(s):  
Oxygen Uptake ◽  
Exercise Test ◽  
Oxidation Rate ◽  
Fat Oxidation ◽  
Incremental Exercise ◽  
Step Test ◽  
Exercise Tests ◽  
Incremental Exercise Test ◽  
Ramp Test ◽  
Maximal Fat Oxidation

Abstract The incremental exercise test is the most common method in assessing the maximal fat oxidation (MFO) rate. The main aim of the study was to determine whether the progressive linear RAMP test can be used to assess the maximal fat oxidation rate along with the intensities that trigger its maximal (FATmax) and its minimal (FATmin) values. Our study comprised 57 young road cyclists who were tested in random order. Each of them was submitted to two incremental exercise tests on an electro-magnetically braked cycle-ergometer - STEP (50 W·3 min-1) and RAMP (~0.278 W·s-1) at a 7-day interval. A stoichiometric equation was used to calculate the fat oxidation rate, while the metabolic thresholds were defined by analyzing ventilation gases. The Student’s T-test, Bland-Altman plots and Pearson’s linear correlations were resorted to in the process of statistical analysis. No statistically significant MFO variances occurred between the tests (p = 0.12) and its rate amounted to 0.57 ± 0.15 g·min-1 and 0.53 ± 0.17 g·min-1 in the STEP and RAMP, respectively. No statistically significant variances in the absolute and relative (to maximal) values of oxygen uptake and heart rate were discerned at the FATmax and FATmin intensities. The RAMP test displayed very strong oxygen uptake correlations between the aerobic threshold and FATmax (r = 0.93, R2 = 0.87, p < 0.001) as well as the anaerobic threshold and FATmin (r = 0.88, R2 = 0.78, p < 0.001). Our results corroborate our hypothesis that the incremental RAMP test as well as the STEP test are reliable tools in assessing MFO, FATmax and FATmin intensities.

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