Nórton L. Oliveira

Criterion-related validity of the 20-m shuttle run test in youths aged 13-19 years

Abstract We assessed the agreement between maximal oxygen consumption ([Vdot]O2max) measured directly when performing the 20-m shuttle run test and estimated [Vdot]O2max from five different equations (i.e. Barnett, equations a and b; Léger; Matsuzaka; and Ruiz) in youths. The 20-m shuttle run test was performed by 26 girls (mean age 14.6 years, s = 1.5; body mass 57.2 kg, s = 8.9; height 1.60 m, s = 0.06) and 22 boys (age 15.0 years, s = 1.6; body mass 63.5 kg, s = 11.5; height 1.70 m, s = 0.01). The participants wore a portable gas analyser (K4b2, Cosmed) to measure [Vdot]O2 during the test. All the equations significantly underestimated directly measured [Vdot]O2max, except Barnetts (b) equation. The mean difference ranged from 1.3 ml · kg−1 · min−1 (Barnett (b)) to 5.5 ml · kg−1 · min−1 (Léger). The standard error of the estimate ranged from 5.3 ml · kg−1 · min−1 (Ruiz) to 6.5 ml · kg−1 · min−1 (Léger), and the percentage error ranged from 21.2% (Ruiz) to 38.3% (Léger). The accuracy of the equations available to estimate [Vdot]O2max from the 20-m shuttle run test is questionable at the individual level. Furthermore, special attention should be paid when comparisons are made between studies (e.g. population-based studies) using different equations. The results of the present study suggest that Barnetts (b) equation provides the closest agreement with directly measured [Vdot]O2max (cardiorespiratory fitness) in youth.

Physical activity in primary and secondary prevention of cardiovascular disease: Overview updated.

Although the observed progress in the cardiovascular disease treatment, the incidence of new and recurrent coronary artery disease remains elevated and constitutes the leading cause of death in the developed countries. Three-quarters of deaths due to cardiovascular diseases could be prevented with adequate changes in lifestyle, including increased daily physical activity. New evidence confirms that there is an inverse dose-response relationship between physical activity and cardiovascular disease and mortality risk. However, participation in moderate to vigorous physical activity may not fully attenuate the independent effect of sedentary activities on increased risk for cardiovascular diseases. Physical activity also plays an important role in secondary prevention of cardiovascular diseases by reducing the impact of the disease, slowing its progress and preventing recurrence. Nonetheless, most of eligible cardiovascular patients still do not benefit from secondary prevention/cardiac rehabilitation programs. The present review draws attention to the importance of physical activity in the primary and secondary prevention of cardiovascular diseases. It also addresses the mechanisms by which physical activity and regular exercise can improve cardiovascular health and reduce the burden of the disease.

Effects of exercise training on endothelial progenitor cells in cardiovascular disease: a systematic review.

ABSTRACTThis review aimed to examine the effects of exercise training on mobilization of endothelial progenitor cells (EPCs) in patients with cardiovascular disease and to discuss the possible mechanisms involved in the process. A computer-aided search on PubMed and PEDro was conducted to identify relevant studies published up to June 2012. Two reviewers independently selected studies for inclusion and extracted data, namely, quantitative assessment of circulating EPCs. Of the 88 identified studies, 13 met the inclusion criteria. The 13 studies enrolled 648 participants, including patients with chronic heart failure, peripheral artery disease, and coronary artery disease. The exercise characteristics varied largely across the studies: exercise duration ranged from 2 wks to 6 mos, session duration ranged from 20 to 60 mins, and exercise intensity was usually calculated using the maximal heart rate (ranging from 75% to 85%) or the peak/maximum oxygen consumption (60%–70%). All studies used aerobic exercise. The great majority of the 13 studies reported significant effects of different exercise regimens on the number of circulating EPCs. In summary, exercise training seems to increase the number of circulating EPCs, which could contribute to vascular regeneration and angiogenesis. These positive effects of chronic exercise seem to be closely related to the bioavailability of nitric oxide, including increased activity of endothelial nitric oxide synthase and antioxidant enzymes, and activation of matrix metalloproteinase 9.

Heart rate variability in myocardial infarction patients: Effects of exercise training

Heart rate variability (HRV) is a simple and noninvasive measure that estimates cardiac autonomic modulation, mainly the parasympathetic contribution. Increased sympathetic and/or decreased parasympathetic nervous activity is seen in post-myocardial infarction (MI) patients. Consequently, these patients present reduced HRV, which has been associated with increased risk of adverse events and mortality. Exercise training, recommended as a complementary therapy for patients with cardiovascular disease, has shown numerous beneficial effects. The main aim of the present manuscript was to provide a critical review of studies investigating the effects of exercise training on cardiac autonomic modulation, through HRV, in MI patients and the possible mechanisms involved. Despite conflicting evidence, exercise training appears to be a useful therapeutic intervention to improve the unbalanced autonomic function of MI patients. Finally, the mechanisms involved are not yet well understood, but nitric oxide bioavailability and angiotensin II levels seem to play an important role.

Effect of 8-week exercise-based cardiac rehabilitation on cardiac autonomic function: A randomized controlled trial in myocardial infarction patients

PURPOSE The purpose of this study is to evaluate the effects of an 8-week exercise-based cardiac rehabilitation program on traditional and nonlinear heart rate variability (HRV) indexes, assessing the potential confounding influences of habitual physical activity (PA) and dietary intake. METHODS In this parallel-group trial, 96 patients (56 ± 10 years old) were randomized to the exercise group (EG) or to the control group (CG) 4 weeks after an acute myocardial infarction. Exercise-based cardiac rehabilitation program consisted of aerobic exercise at 70% to 85% of maximal heart rate for 3 sessions per week plus usual care. The CG received only usual care. The baseline and final assessments comprised resting short-term HRV (primary outcome) by a Polar R-R recorder under controlled breathing (12 breaths per minute), habitual PA by accelerometers, and dietary intake by a 4-day food diary. RESULTS Two patients in each group dropped out and were not included in the intention-to-treat analysis. In the remaining 92 patients (EG = 47 and CG = 45), at baseline, only a difference in the proportion of nitrate medication use was significant between groups. After 8 weeks, no significant changes were found between groups on traditional and nonlinear HRV indexes (eg, ln HF, EG from 5.7 ± 1.5 to 5.9 ± 1.3 and CG from 5.5 ± 1.6 to 5.5 ± 1.5), habitual PA, and dietary intake. CONCLUSION Eight weeks of exercise-based cardiac rehabilitation program is an insufficient stimulus to improve cardiac autonomic function in post-myocardial infarction patients under optimal medication and with high levels of traditional and nonlinear HRV indexes at baseline.

The effects of exercise training on arterial stiffness in coronary artery disease patients: a state-of-the-art review

The purpose of this state‐of‐the‐art review was to examine the effects of exercise training on arterial stiffness (AS) in patients with coronary artery disease (CAD). A PubMed and SCOPUS literature search was conducted up to March of 2013. Two authors performed the selection of the studies and the subsequent data extraction (e.g. information on study design, exercise programme characteristics and outcome measures). Of 34 papers identified, only five studies met the inclusion criteria, with no one being a randomized controlled trial. Within the selected studies, the sample size varied between 28 and 119 patients, with mean ages ranging from 48 to 67 years old in patients with CAD after an acute myocardial infarction, coronary artery bypass graft or percutaneous transluminal coronary angioplasty. Although all studies utilized the aerobic exercise mode, the other characteristics of the exercise programmes varied largely between the studies: programme length (from 6 to 20 weeks), exercise duration (15–20 to 50 min) and exercise intensity, which was based on heart rate reserve (40 to 85%) or heart rate at anaerobic threshold or ventilatory threshold. All the three studies evaluating pulse wave velocity, as well as one of two studies that assessed the augmentation index, reported significant reductions on those variables after exercise training. Results indicated that the majority of the AS and related measures improved after the different exercise training programmes. However, these results need to be confirmed in future randomized clinical studies controlling potential confounders.

Comparison Between Swimming VO2peak and VO2max at Different Time Intervals

Accepting that the evaluation of the aerobic energy system contribution is very important for swimming train- ing diagnostics purposes and that oxygen uptake kinetics (VO2) is one of the most used parameters in that task, we pur- posed to assess the variability of the peak VO2 and VO2max values obtained in a 200 m front crawl effort, using five dif- ferent presentation intervals: breath-by-breath and average of 5, 10, 15, and 20 s. Ten male high-level swimmers per- formed a 200 m front crawl effort at maximal velocity being attached to a respiratory valve that allowed to directly meas- ure the breath-by-breath VO2 kinetics. VO2 peak was accepted as the highest single value on breath-by-breath sampling and VO2max was considered as the average values of the 5, 10, 15 and 20 s sampling obtained during the test. The ob- tained VO2peak and VO2max mean values in breath-by-breath and averaged 5 s sampling were similar to those described in the literature for experienced male competitive swimmers. Higher VO2 values were observed for breath-by-breath sampling, being observed differences between that data acquisition method and all the other time intervals (5, 10, 15 and 20 s). Differences were also visible between the 5 s averaging and the other less frequent data acquisitions considered (10, 15 and 20 s), evidencing that less frequent sampling frequencies underestimate the VO2max values. More future research about this topic, also conducted in real competition conditions, i.e., in swimming-pool (not in running or cycle ergome- ters) is needed.

Exercise-based cardiac rehabilitation increases daily physical activity of patients following myocardial infarction: subanalysis of two randomised controlled trials.

OBJECTIVE To assess the effects of an exercise-based cardiac rehabilitation programme on daily physical activity levels of patients following myocardial infarction. DESIGN Subanalysis of two randomised, prospective controlled trials. SETTING Outpatient clinic of a secondary hospital. PARTICIPANTS Fifty consecutive patients randomised to the exercise group {n=25; 23 males; mean age 54 [standard deviation (SD) 9] years} or the control group [n=25; 20 males; mean age 58 (SD 9) years]. INTERVENTIONS The exercise group participated in an 8-week aerobic exercise programme plus usual medical care and follow-up. The control group received usual medical care and follow-up. MAIN OUTCOME MEASURES The primary outcome measure was change in time spent undertaking moderate-to-vigorous physical activity per day, assessed by accelerometer over 7 consecutive days. Secondary outcome measures were cardiorespiratory fitness, body mass, and resting blood pressure and heart rate. RESULTS Moderate-to-vigorous physical activity levels increased significantly in the exercise group [43.2 (SD 36.3) to 53.5 (SD 31.9) minutes/day, P=0.030], and remained unchanged in the control group [40.8 (SD 26.2) to 36.8 (SD 26.5) minutes/day, P=0.241] from baseline to the end of the programme. Cardiorespiratory fitness increased significantly in the exercise group (mean difference 2.8; 95% of the difference 1.3 to 4.4ml/kg/minute, P=0.001) after the 8-week programme. CONCLUSIONS In patients under optimal medication following myocardial infarction, participation in an 8-week exercise-based cardiac rehabilitation programme was found to improve physical activity levels consistent with health-related benefits. Future studies are needed to determine whether the increase in physical activity is maintained in the long term.

Excess Postexercise Oxygen Consumption is Unaffected by the Resistance and Aerobic Exercise Order in an Exercise Session

Oliveira, NL and Oliveira, J. Excess postexercise oxygen consumption is unaffected by the resistance and aerobic exercise order in an exercise session. J Strength Cond Res 25(10): 2843–2850, 2011—The main purpose of this study was to compare the magnitude and duration of excess postexercise oxygen consumption (EPOC) after 2 exercise sessions with different exercise mode orders, resistance followed by aerobic exercise (R–A); aerobic by resistance exercise (A–R). Seven young men (19.6 ± 1.4 years) randomly underwent the 2 sessions. Aerobic exercise was performed on a treadmill for 30 minutes (80–85% of reserve heart rate). Resistance exercise consisted of 3 sets of 10 repetition maximum on 5 exercises. Previous to the exercise sessions, &OV0312;O2, heart rate, &OV0312;CO2, and respiratory exchange rate (RER) were measured for 15 minutes and again during recovery from exercise for 60 minutes. The EPOC magnitude was not significantly different between R–A (5.17 ± 2.26 L) and A–R (5.23 ± 2.48 L). Throughout the recovery period (60 minutes), &OV0312;O2 and HR values were significantly higher than those observed in the pre-exercise period (p < 0.05) in both exercise sessions. In the first 10 minutes of recovery, &OV0312;CO2 and RER declined to pre-exercise levels. Moreover, &OV0312;CO2 and RER values in A–R were significantly lower than in R–A. In conclusion, the main result of this study suggests that exercise mode order does not affect the EPOC magnitude and duration. Therefore, it is not necessary for an individual to consider the EPOC when making the decision as to which exercise mode is better to start a training session.

Treadmill walking with load carriage increases aortic pressure wave reflection.

INTRODUCTION AND OBJECTIVES The study examined the effects of treadmill walking with load carriage on derived measures of central pressure and augmentation index in young healthy subjects. METHODOLOGY Fourteen male subjects (age 31.0 ± 1.0 years) volunteered in this study. Subjects walked 10 minutes on a treadmill at a speed of 5 km/h carrying no load during one session and a load of 10% of their body weight on both upper limbs in two water carboys with handle during the other session. Pulse wave analysis was performed at rest and immediately after exercise in the radial artery of the right upper limb by applanation tonometry. RESULTS The main result indicates that walking with load carriage sharply increased augmentation index at 75 bpm (-5.5 ± 2.2 to -1.4 ± 2.2% vs. -5.2 ± 2.8 to -5.5 ± 2.1%, p<0.05), and also induced twice as high increments in central pulse pressure (7.4 ± 1.5 vs. 3.1 ± 1.4 mmHg, p<0.05) and peripheral (20.5 ± 2.7 vs. 10.3 ± 2.5 mmHg, p<0.05) and central systolic pressure (14.7 ± 2.1 vs. 7.4 ± 2.0 mmHg, p<0.05). CONCLUSIONS Walking with additional load of 10% of their body weight (aerobic exercise accompanied by upper limb isometric contraction) increases derived measures of central pressure and augmentation index, an index of wave reflection and arterial stiffness.