Verification phase to confirm the 'true' VO2max in apparently healthy adults : meta-analytical analysis of the criteria adopted
Background: The cardiopulmonary exercise test (CPET) is considered the gold standard method for assessing the maximum aerobic power expressed by the maximum oxygen consumption (VO2max). The primary criterion for confirming the 'true' VO2max is based on obtaining a VO2 plateau at the end of the CPET, or on secondary criteria, such as peak values for respiratory exchange ratio, percentage of maximum heart rate predicted by age, or concentrations of blood lactate after CPET. However, the VO2 plateau is often not observed. On the other hand, the adoption of secondary criteria may result in an inaccurate VO2maxassessment. As an alternative procedure to overcome these limitations, it has been proposed to conduct an additional exercise session after the incremental phase of the CPET, called the 'verification phase'. However, doubts remain regarding the validity and application of this approach as a necessary procedure for measuring VO2max. The aim of this Master's Dissertation was to investigate, through meta-analysis, the application of the verification phase as a procedure for confirming the VO2max obtained in CPET in healthy adults. Additionally, the influence of criteria adopted in the verification phase on the effect sizes of the differences vs. TCPE were analyzed.
Methods: MEDLINE (accessed through PubMed), Web of Science, SPORTDiscus, and Cochrane (accessed through Wiley) were searched using a combination of medical subject heading (MeSH) descriptors in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Meta-analyses were performed to investigate the mean differences between the highest VO2 and heart rate responses during a CPET and verification phase. Subgroup and meta-regression analyses were used to assess potential moderating factors.
Results: Seventy-eight studies met the eligibility criteria (total sample of 1,634 participants; age range 19-68 yr.). The VO2max vs. VO2 were similar [n = 52, mean difference = 0.02 (95% CI = -0.01 to 0.06) L/min, P = 0.17]. The highest VO2 was not affected by sex, cardiorespiratory fitness level, CPET modality, CPET protocol design, or how the verification phase is performed. However, the highest heart rate attained was significantly lower in the verification phase [n = 36, mean difference = 2.7 (95% CI = 2.0 to 3.5) bpm, P < 0.00001].
Conclusion: The verification phase seems a robust procedure for confirming true VO2max among apparently healthy adults. Using maximal heart rate to help verify attainment of VO2max , however, currently cannot be recommended until further research establishes more robust procedures.
cardiopulmonary exercise test, oxygen consumption, criteria, measurement and evaluation, plateau, cardiorespiratory fitness.
Methods: In this study, we included 24 men classified according to ambulatory BP monitoring (ABPM) as normotensive [age: 40.7±2.8 years; 24-h systolic/ diastolic blood pressure (SBP/ DBP): 120.6±1.6/73.9±1.2 mmHg] or hypertensive [age: 39.2±2.3 years; 24-h (SBP/ DBP): 139.3±2.6/ 86.4±2.1 mmHg]. Each participant underwent a non-exercise control session (CTL) and three cycle sessions. The aerobic exercise protocols were composed of two 300 kcal isocaloric sessions, with intensities of 50% (long moderate, L-MOD) and 70% (vigorous, VIG) of oxygen uptake reserve (VO2R) and one session with 150 kcal at 50% of VO2R (short moderate, S-MOD). Aortic systolic pressure (aoSP), aortic pulse pressure (aoPP), augmentation pressure (AP), augmentation index (AIx), heart rate (HR), and AIx normalized by HR 75 bpm (AIx@75) were determined using applanation tonometry 10 min before, and 30- and 70-min post-intervention in a supine position. ABPM and heart rate variability indices (HRV) were determined during the day, at night, and for 18 h after each intervention.
Results: Compared to CTL, only the VIG elicited significant changes in aoSP [70 min (∆ -11.7 mmHg)], aoPP [70 min (∆ -7.4 mmHg)], AP [30 min (∆ -5.7 mmHg); 70 min (∆ -7.3 mmHg)], AIx [30 min (∆ -15.3%); 70 min (∆ -16.4%)], and AIx@75 [30 min (∆ -12.8%); 70 min (∆: 13.9%)] in the hypertensive men. All moderate exercise sessions mitigated the increase in aoSP responses after the CTL session in these same individuals. Regarding ABPM, it was not possible to observe BP reduction during the day, night, and 18 h regardless of the exercise protocols and the groups evaluated. However, when considered only the first hour after the VIG, both groups showed decreased in SBP [normotensive (∆ -6 mmHg); hypertensive (∆ -9 mmHg)]. On the other hand, no modifications could be observed for the HRV components in any situation described above.
Conclusion: Although both groups benefited from the vigorous exercise protocol through peripheral BP reduction, hypertensive individuals obtained better responses, as it was also possible to observe a decrease in central BP and the pulse wave reflection. In addition, moderate-intensity exercises, regardless of volume, were able to attenuate the central pressure increased in hypertensive individuals, which could be adopted as an initial strategy in conditioning programs.
exercise, post-exercise hypotension, vascular stiffness, ambulatory blood pressure monitoring, ambulatory electrocardiography.
LIMA, Tainah de Paula. Acute effects of cycling exercise with different intensities and volumes on blood pressure, pulse wave reflection, and cardiac autonomic control in hypertensive and normotensive men. 2019. 91f. Thesis (Doctorate in Medical Sciences) - Faculty of Medical Sciences, State University of Rio de Janeiro, Rio de Janeiro, 2019.
Methods: The sample consisted of 10 subjects (age: 72.9 ± 6.0 years; body mass: 70.5 ± 9.9 kg, height: 161.1 ± 8.0 cm). The experiment was carried out during five visits to the laboratory. On the first visit, anthropometric measurements, clinical examination, anamnesis and cardiopulmonary exercise test were performed. In the second visit, a load test of 10 maximum repetitions (RM) was performed for the leg press, rowing machine, leg extension machine, bench press machine, leg curl machine, shoulder press machine, leg adductor machine, and elbow flexion on the low pulley. The last 4 visits were experimental sessions [SE: 3 sets with 10 repetitions at 80% of 10RM; AE: power output adjusted to 60-65% of oxygen uptake reserve (VO2R); CE: SE + AE with the total energy cost equivalent to the value observed during SE, half of these calories being dedicated to SE and the other half to AE; control].
Results: The main results revealed that the exercise bouts showed a similar energy cost (126.9 kcal), but different durations (AE: 26.6 min; CE: 43.3 min; SE: 61.8 min - P <0.001). With regard to cardiorespiratory responses, it was observed that the bouts were sustained at different percentages of VO2R (SE: 24%; CE: 43%; AE: 74% - P <0.01). Finally, EPOC and energy cost were higher in the AE compared to the EC and EF bout, which did not differ between them (AE: 8 ± 2.3 L; 40.1 ± 11.7 kcal versus EC: 5.4 ± 2.3 L, 26.9 ± 11.5 kcal versus 5.6 ± 1.2 L, 28.1 ± 5.8 kcal - P <0.001).
Conclusion: AE, CE and SE bouts exhibit different durations in older people. The continuous and intermittent nature of the activities exerted a diversified influence on the sustained effort intensities during the exercise bouts. Exercise bouts matched by energy cost have different repercussions on EPOC, with the first minutes of recovery responsible for the greatest impact in favor of the AE when compared to the other investigated exercise modalities. Therefore, when the purpose of the prescription is aimed at obtaining a higher total energy cost (kcal expended during exercise and recovery), the AE bout should be preferred in older people.
energy expenditure, energy cost, oxygen consumption, heart rate, weight control, weight loss.
PILON, Rui. Cardiorespiratory responses, energy cost and EPOC induced by strength, aerobic and concurrent exercise bouts in older people. 2018. 67 f. Dissertation (Academic Master in Physical Activity Sciences) - Salgado de Oliveira University, Rio de Janeiro, 2018.
Methods: Nine subjects (5 males and 4 females, aged 63–80 years) visited the laboratory for clinical screening, and anthropometrical, resting and maximal VO2assessments. Thereafter, subjects performed an Ex Rx circuit, consisting of a single circuit alternating aerobic and resistance exercises on outdoor exercise equipment using body mass as the load (total of 9 exercises, 1-2 sets of 15 repetition). Expired gases were collected during exercise bouts via a portable gas analysis system.
Results: The mean observed energy cost value of 169.1 kcal was slightly greater than the minimum value of 150 kcal reported in the ACSM’s guidelines (p = 0.018). Like energy cost, all the intensity markers adopted to analyze the physiological strain induced by the Ex Rx circuit significantly exceeded their reference values for moderate-intensity [reference values: 3.2 METs (mean observed value = 4.6 METs, p = 0.002); 40% VO2R (mean observed value = 51.5%, p = 0.040); 40% of heart rate reserve (mean observed value = 64.1%, p < 0.001), according to the ACSM's guidelines.
Conclusion: A single bout of Ex Rx circuit performed in TAAs at Rio de Janeiro City was able to induce a physiological strain (i.e. energy cost and intensity) compatible with the ACSM recommendations for eliciting health benefits among older adults.
concurrent training, circuit training, outdoor academies, seniors, cardiorespiratory responses, energy expenditure.
GOMES, Gabrielle da Silva Moreira. Physiological strain induced by a single bout of concurrent exercise at Third Age Academies (TAAs) of Rio de Janeiro City: a study in older adults. 85 f. 2018. Dissertation (Academic Master in Exercise and Sport Sciences) - Institute of Physical Education and Sports, State University of Rio de Janeiro, Rio de Janeiro, 2018.
Methods: This study was conducted on a sample of prehypertensive individuals, aged 20-40 years. Each subject visited the laboratory five times. On the first visit, subjects participated in an orientation session to familiarize them with equipment and test protocols, completed a pre-participation questionnaire for cardiovascular risk and were screened for BP to ensure they met the study inclusion criteria. On the second visit, anthropometric measurements were taken followed by resting oxygen uptake (VO2), BP and HRV assessments for 60 min (control session). On the third visit, a maximal cardiopulmonary exercise test (CPET) on a cycle ergometer was performed for determining VO2max. On two subsequent visits, subjects underwent a continuous bout (CONT) with 400 kcal and an accumulated bout split into two x 200 kcal (INTER1 and INTER2) at 75% of VO2 reserve. BP and cardiac autonomic control were monitored 10 min before and for 60 min after each exercise bout and control session in a supine position.
Results: Compared to the control session, systolic BP (SBP), diastolic BP (DBP) and mean arterial pressure (MAP) decreased similarly after CONT (SBP: ∆-3.4 mmHg, P < 0.001; MAP: ∆-2.5 mmHg, P = 0.001) and INTER2 (SBP: ∆-4.4 mmHg, P < 0.001; DBP: ∆-2.7 mmHg, P = 0.045; MAP: ∆-3.3 mmHg, P = 0.001). However, INTER2 elicited greater postexercise hypotension (PEH) than INTER1 (SBP and MAP: ∆-2.0 and ∆-1.8 mmHg, respectively, P < 0.05). Concomitant to PEH, sympathetic (low frequency band, LF) and parasympathetic (high frequency band, HF) activity increased (P < 0.001) and decreased (P < 0.001), respectively, from baseline, increasing the sympathovagal balance (LF:HF ratio) (P < 0.001) that was inversely related to ΔSBP and ΔDBP (r = -0.64 to -0.71; P < 0.05).
Conclusion: Continuous or accumulated bouts of cycling matched by energy expenditure elicit similar PEH; however, lower BP decreases were also observed after the cycling bout involving lower exercise volume (INTER1: 200 kcal). The results also indicate that the recovery pattern of cardiac autonomic control may have an important role in eliciting PEH.
cardiovascular physiology, postexercise hypotension, energy expenditure, health promotion.
FONSECA, Guilherme de Freitas. Acute effects of continuous and accumulated isocaloric cycling bouts on blood pressure in prehypertensives. 95f. Dissertation (Academc Master in Rehabilitation Sciences) - Augusto Motta University Center, Rio de Janeiro, Rio de Janeiro, 2017
Methods: A heterogeneous cohort of 114 healthy men, aged 18 to 38 yr, volunteered to participate in two studies. First, 100 men [lower CRF: n = 48, VO2max <50,0 mL•kg-1•min-1; higher CRF: n = 52, VO2max ≥ 50,0 mL•kg-1•min-1] visited the laboratory twice to explore the association between directly assessed VO2max and resting VO2 . Second, 14 men performed a 30-min bout of running at 8.0 km•h-1 (8.3 METs according to the Compendium of Physical Activities) to investigate the use of the MET to quantify the energy cost of treadmill running.
Results: The VO2max was strongly positively correlated with resting VO2 (R = 0.68, P < 0.001). The mean observed resting VO2 values of 3.28 (n = 100) and 3.07 (n = 14) mL•kg-1•min-1 were significantly lower than the standardized value of 3.5 mL•kg-1•min-1 (P < 0.001 and P = 0.005, respectively). When compared to the standardized value, groups with lower CRF demonstrated significantly lower mean observed resting VO2 values of 3.06 (1st part of the study, P < 0.001) and 2.67 (2nd part of the study, P < 0.001) mL•kg-1•min-1. However, no significant difference was observed between standardized and observed resting VO2 values for the groups with higher CRF (1st part of the study: P = 0.87; 2nd part of the study: P = 0.78). Hence the observed values for METmax intensity and the energy cost of treadmill running were significantly underestimated when calculated using the standardized resting VO2 value of 3.5 mL•kg-1•min-1 (P = 0.005 to P < 0.001) only for the groups with lower CRF.
Conclusion: The standardized MET value considerably overestimated observed resting VO2 in men with lower CRF. Direct determination of resting VO2 is therefore preferred to improve the accuracy of the aforementioned applications in this population.
exercise prescription, guidelines and recommendations, physical activity assessment, physical fitness, resting oxygen uptake.
ÁZARA, Helouane Martinho. Accuracy of metabolic equivalents (METS) for prescribing aerobic exercise from estimated and measured 1-MET value in healthy men. 102f. Dissertation (Academc Master in Rehabilitation Sciences) - Augusto Motta University Center, Rio de Janeiro, 2017.
Methods: Thirty physically active men [mean (minimum–maximum): age, 24 (18-34) yr; height, 181 (163-198) cm; body mass, 84 (59-116) kg; body mass index, 25 (20-30) kg•m-2; percentage body fat, 18% (9%-27%) visited the laboratory three times for anthropometrical and resting VO2 assessments, and perform cycling and running CPETs. Ten men visited the laboratory twice more to investigate the validity of the %HRR-%VO2R relationships during isocaloric bouts of cycling and running at 75% VO2R with energy expenditures of 400 kcals.
Results: The %VO2R was significantly lower than the %HRR in the CPETs, especially during running (P < 0.001). During isocaloric exercise bouts, mean %HRR-%VO2R differences of 6.5% and 7.0% were observed for cycling and running, respectively (P = 0.007 to P < 0.001). The %HRR and %VO2R increased over time (P < 0.001), the rate of which was influenced by exercise modality (P < 0.001). On average, heart rate was 5 (P = 0.007) and 8 (P < 0.001) beats•min-1 higher than predicted from the second time quartile for cycling and running, respectively; however, observed VO2 was lower than predicted during all quartiles for cycling, and the first quartile for running. Consequently, time to achieve the target energy expenditure was greater than predicted (P < 0.01).
Conclusion: The %HRR-%VO2R relationship observed during CPET data did not accurately transpose to prolonged isocaloric bouts of cycling and running. Additionally, work rates defined by the ACSM equations for cycling and running overestimated VO2 and energy expenditure.
cardiopulmonary exercise testing, isocaloric exercise, kilocalories, training intensity.
GUIMARÃES, Giovanna Caruso. Validity of the relationship between heart rate reserve and oxygen uptake reserve for exercise prescription of cycling and running. 100f. Dissertation (Academc Master in Rehabilitation Sciences) - Augusto Motta University Center, Rio de Janeiro, 2017.