Vo2max and exercise performance (original) (raw)
Related papers
faculty.css.edu
ROBERT A. ROBERGS An Exercise Physiologist's "Contemporary" Interpretations Of The "Ugly And Creaking Edifices" Of The VO 2 max Concept. JEPonline, 2001 4(1):1-44. The recent debate over the validity of traditional interpretations of the concept of VO 2 max has prompted the writing of this commentary. Rather than provide another "classic" interpretation of how VO 2 max is interpreted within exercise physiology (1), a more "contemporary" interpretation than that of Noakes (2-4) is provided by an exercise physiologist welltrained and widely published in exercise physiology and biochemistry. It is this author's contention that Noakes (2-4), as well as Bassett and Howley (1), have overemphasized the classic research of Hill and related physiological interpretations pertaining to VO 2 max. Nevertheless, Noakes deserves to be commended for his candor in constructively criticizing how the field of exercise physiology has researched and interpreted findings on the concept of VO 2 max. Despite Noakes' criticisms of the validity of the concept of a VO 2 plateau at VO 2 max, a thorough review of research, as well as the presentation of original data in this manuscript, indicates that the VO 2 plateau is a measurable phenomenon in most subjects. Noakes' alternative theories for limitations to VO 2 during incremental exercise to volitional exhaustion are challenged based on past research evidence. The limitations to VO 2 during incremental exercise are shown to be population and environmental condition specific, and the concept of main determinants of VO2max for all people and conditions is shown to be an oversimplification and inaccurate. Novel interpretations of recent research are presented to provide a more systems oriented and research-based approach to understanding the determinants of the limitation to the continued increase in VO 2 during incremental exercise testing. The challenges that confront exercise physiologists are to better define their profession, increase the standards and quality of academic preparation, improve research design, and better justify certain physiological interpretations when researching VO 2 max and related topics.
British Journal of Sports Medicine, 2013
Background There remains considerable debate regarding the limiting factor(s) for maximal oxygen uptake (VO 2max ). Previous studies have shown that the central circulation may be the primary limiting factor for VO 2max and that cardiac work increases beyond VO 2max . Aim We sought to evaluate whether the work of the heart limits VO 2max during upright incremental cycle exercise to exhaustion. Methods Eight trained men completed two incremental exercise trials, each terminating with exercise at two different rates of work eliciting VO 2max (MAX and SUPRAMAX). During each exercise trial we continuously recorded cardiac output using pulse-contour analysis calibrated with a lithium dilution method. Intra-arterial pressure was recorded from the radial artery while pulmonary gas exchange was measured continuously for an assessment of oxygen uptake. Results The workload during SUPRAMAX (mean±SD: 346.5±43.2 W) was 10% greater than that achieved during MAX (315±39.3 W). There was no significant difference between MAX and SUPRAMAX for Q (28.7 vs 29.4 L/min) or VO 2 (4.3 vs 4.3 L/min). Mean arterial pressure was significantly higher during SUPRAMAX, corresponding to a higher cardiac power output (8.1 vs 8.5 W; p<0.06). Conclusions Despite similar VO 2 and Q, the greater cardiac work during SUPRAMAX supports the view that the heart is working submaximally at exhaustion during an incremental exercise test (MAX).
Journal of Applied Physiology, 2008
Reviewing evidence for and against a Central Governor that limits an individual's maximal oxygen intake (2, 4), I am impressed that although this hypothesis was formulated some 11 years ago, it still lacks support outside the proponent's laboratory. I note also that, perhaps because of an inappropriate test protocol, Noakes has consistently found difficulty in reaching first base in this area of research, the demonstration of an oxygen consumption plateau. In contrast, Ekblom and colleagues (2) have had no problems in this regard. Noakes (4) currently argues that a Central Governor is essential to prevent the development of a dangerous myocardial ischemia. However, anyone who has exercised older adults will know that a substantial proportion of such individuals manifest myocardial ischemia. Ultraendurance athletes also develop myocardial ischemia (3), and indeed may use this as a stimulus to cardiac hypertrophy. Does this imply that ultraendurance athletes and old people have carelessly broken their Central Governors? Noakes also cites (4), with apparent approval, the argument of A. V. Hill (3) that the Governor dissuades the heart from making an excessive effort that would reduce the oxygen saturation of arterial blood. Again, the weight of current evidence is that well-motivated athletes do reduce their arterial oxygen saturations (1). Moreover, it would be hard to imagine how the mechanism postulated by Noakes could evolve, since the forces of natural selection have not focused on the ability to perform a maximal oxygen intake test.
Incidence of the oxygen plateau at VO 2 max during exercise testing to volitional fatigue
Journal of Exercise Physiology Online
Fatigue. JEPonline, 3(4): 2000. The purpose of this study was to better clarify the VO 2 response to exercise to VO 2 max by comparing data derived from different time averaging intervals and exercise protocols. Sixteen active subjects (12 men and 4 women, mean age, height, weight, and VO 2 max = 31.6±8.9 yr, 172.0±6.6 cm, 70.8±12.7 kg, 3,212±652 mL/min) completed three different VO 2 max tests on a cycle ergometer (a 25 Watt/min ramp protocol (R), a 75 Watt/3 min step protocol (S), and a 25 Watt/min ramp protocol (H) under hypoxic conditions (F I O 2 = 15 %, P B = 635 mm Hg) on separate days. During each test, subjects breathed humidified air from a Tissot tank, and breath-by-breath gas exchange was obtained by a Medical Graphics metabolic cart. All breath-by-breath data were smoothed using an 11-breath moving average. These data were then time-averaged into 15, 30, and 60 s sampling intervals. Criteria for attainment of VO 2 max included two of the following: RER > 1.1, maximal heart rate (HR) within 10 b/min of the calculated value, or an O 2 plateau (∆VO 2 < 50 mL/min) with an increase in power output. Average VO 2 max was significantly lower (F (2, 30) = 84.37, p < .001) for the H (2,532±562 mL/min) compared to the S (3,112±660 mL/min) and R (3,212±651 mL/min) protocols. Average maximal RER was significantly different (F (2, 30) = 3.77, p < .05) across protocols, however no differences were exhibited between means. Average HR at VO 2 max was significantly lower (F (2, 30) = 12.26, p < .001) during the H trial (169±13 b/min) compared to the R (176±9 b/min) and S (178±9 b/min) protocols. The incidence at which subjects demonstrated a plateau in VO 2 for all protocols combined were 100, 100, 57 and 8 % for the 11 breath, 15 s, 30 s and 1 min averaging, respectively. Data of the change in VO 2 between VO 2 max and the closest neighboring data point revealed that variability was greatest for the longer time averaged data. This response was similar for each protocol. These findings show that shorter sampling intervals (breath-by-breath and 15 s) are most suitable for the detection of the VO 2 plateau during progressive exercise to VO 2 max. In addition, ramp and step protocols produce similar results, and acute normobaric hypoxia does not decrease the incidence of a VO 2 plateau at VO 2 max using 11 breath or 15 s time averaging procedures.
Effect of Exercise Intensity on Relationship between &OV0312;O2max and Cardiac Output
Medicine & Science in Sports & Exercise, 2004
LEPRETRE, P.-M., J.-P. KORALSZTEIN, and V. L. BILLAT. Effect of Exercise Intensity on Relationship between V O 2max and . Purpose: The purpose of this study was to determine whether the maximal oxygen uptake (V O 2max ) is attained with the same central and peripheral factors according to the exercise intensity. Methods: Nine well-trained males performed an incremental exercise test on a cycle ergometer to determine the maximal power associated with V O 2max (pV O 2max ) and maximal cardiac output (Q max ). Two days later, they performed two continuous cycling exercises at 100% (tlim100 ϭ 5 min 12 s Ϯ 2 min 25 s) and at an intermediate work rate between the lactate threshold and pV O 2max (tlim⌬50 ϭ 12 min 6 s Ϯ 3 min 5 s). Heart rate and stroke volume (SV) were measured (by impedance) continuously during all tests. Cardiac output (Q ) and arterial-venous O 2 difference (a-vO 2 diff) were calculated using standard equations. Results: Repeated measures ANOVA indicated that: 1) maximal heart rate, V E, blood lactate, and V O 2 (V O 2max ) were not different between the three exercises but Q was lower in tlim⌬50 than in the incremental test (24.4 Ϯ 3.6 L·min Ϫ1 vs 28.4 Ϯ 4.1 L·min Ϫ1 ; P Ͻ 0.05) due to a lower SV (143 Ϯ 27 mL·beat Ϫ1 vs 179 Ϯ 34 mL·beat Ϫ1 ; P Ͻ 0.05), and 2) maximal values of a-vO 2 diff were not significantly different between all the exercise protocols but reduced later in tlim⌬50 compared with tlim100 (6 min 58 s Ϯ 4 min 29 s vs 3 min 6 sϮ 1 min 3 s, P ϭ 0.05). This reduction in a-vO 2 diff was correlated with the arterial oxygen desaturation (SaO 2 ϭ Ϫ15.3 Ϯ 3.9%) in tlim⌬50 (r ϭ Ϫ0.74, P ϭ 0.05). Conclusion: V O 2max was not attained with the same central and peripheral factors in exhaustive exercises, and tlim⌬50 did not elicit the maximal Q . This might be taken into account if the training aim is to enhance the central factors of V O 2max using exercise intensities eliciting V O 2max but not necessarily Q max .
Evidence that a central governor regulates exercise performance during acute hypoxia and hyperoxia
The Journal of experimental biology, 2001
An enduring hypothesis in exercise physiology holds that a limiting cardiorespiratory function determines maximal exercise performance as a result of specific metabolic changes in the exercising skeletal muscle, so-called peripheral fatigue. The origins of this classical hypothesis can be traced to work undertaken by Nobel Laureate A. V. Hill and his colleagues in London between 1923 and 1925. According to their classical model, peripheral fatigue occurs only after the onset of heart fatigue or failure. Thus, correctly interpreted, the Hill hypothesis predicts that it is the heart, not the skeletal muscle, that is at risk of anaerobiosis or ischaemia during maximal exercise. To prevent myocardial damage during maximal exercise, Hill proposed the existence of a 'governor' in either the heart or brain to limit heart work when myocardial ischaemia developed. Cardiorespiratory function during maximal exercise at different altitudes or at different oxygen fractions of inspired ai...
2014
VO 2 is expressed as the product of cardiac output and O 2 extraction by the Fick equation. During the incremental exercise test and constant high-intensity exercise test, VO 2 results in the attainment of maximal O 2 uptake at exhaustion. However, the differences in the physiological components, cardiac output and muscle O 2 extraction, have not been fully elucidated. We tested the hypothesis that constant exercise would result in higher O 2 extraction than incremental exercise at exhaustion. [Subjects] Twenty-five subjects performed incremental exercise and constant exercise at 80% of their peak work rate. [Methods] Ventilatory, cardiovascular, and muscle oxygenation responses were measured using a gas analyzer, Finapres, and near-infrared spectroscopy, respectively. [Results] VO 2 was not significantly different between the incremental exercise and constant exercise. However, cardiac output and muscle O 2 saturation were significantly lower for the constant exercise than the incremental exercise at the end of exercise. [Conclusion] These findings indicate that if both tests produce a similar VO 2 value, the VO 2 in incremental exercise would have a higher ratio of cardiac output than constant exercise, and VO 2 in constant exercise would have a higher ratio of O 2 extraction than incremental exercise at the end of exercise.
BMJ Open Sport & Exercise Medicine
BackgroundThe influence of endurance training intensity and adaptation on serum cardiac markers is poorly understood and controversial; however, no enough data observed the association of serum cardiac markers with VO2max. Therefore, we aimed to investigate whether serum cardiac markers are associated with maximum oxygen consumption (VO2max) in response to 12-week endurance training on amateur athletes.Methods15 apparently healthy male amateur athletes with 19.47 ± 1.30 years of age were recruited and participated in endurance training with 70%–80% maximal heart rate intensity for 35 min per session for the first week and 2 min increments each week from the second to the last week for a period of 12 weeks. VO2max and serum cardiac markers (lactate dehydrogenase [LDH], creatine kinase myocardial band (CK-MB) and cardiac troponin I [CTnI]) were assessed at the beginning of the training and after 12-week endurance training.ResultsThe result of CTnI indicated significantly (p < 0.01)...