Evaluation of a graded exercise test to determine peak fat oxidation in individuals with low cardiorespiratory fitness
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The maximal capacity to utilise fat (peak fat oxidation, PFO) may have implications for health and ultra-endurance performance and is commonly determined by incremental exercise tests employing 3-min stages. However, 3-min stages may be insufficient to attain steady-state gas kinetics, compromising test validity. We assessed whether 4-min stages produce steady-state gas exchange and reliable PFO estimates in adults with peak oxygen consumption < 40 mL·kg-1·min-1. Fifteen participants (9 females) completed a graded test to determine PFO and the intensity at which this occurred (FATMAX). Three short continuous exercise sessions (SCE) were then completed in a randomised order, involving completion of the graded test to the stage (i) preceding, (ii) equal to (SCEequal), or (iii) after the stage at which PFO was previously attained, whereupon participants then continued to cycle for 10 min at that respective intensity. Expired gases were sampled at minutes 3-4, 5-6, 7-8, and 9-10. Individual data showed steady-state gas exchange was achieved within 4 min during SCEequal. Mean fat oxidation rates were not different across time within SCEequal nor compared with the graded test at FATMAX (both p > 0.05). However, the graded test displayed poor surrogate validity (SCEequal, minutes 3-4 vs. 5-6, 7-8, and 9-10) and day-to-day reliability (minutes 3-4, SCEequal vs. graded test) to determine PFO, as evident by correlations (range: 0.47-0.83) and typical errors and 95% limits of agreement (ranges: 0.03-0.05 and ±0.09-0.15 g·min-1, respectively). In conclusion, intraindividual variation in PFO is substantial despite 4-min stages establishing steady-state gas exchange in individuals with low fitness. Individual assessment of PFO may require multiple assessments.Keywords:
Intensity
Incremental exercise
Purpose: This study had 2 objectives: (1) to examine whether the validity of the supramaximal verification test for maximal oxygen uptake ( V˙O2max ) differs in children and adolescents when stratified for sex, body mass, and cardiorespiratory fitness and (2) to assess sensitivity and specificity of primary and secondary objective criteria from the incremental test to verify V˙O2max . Methods: In total, 128 children and adolescents (76 male and 52 females; age: 9.3-17.4 y) performed a ramp-incremental test to exhaustion on a cycle ergometer followed by a supramaximal test to verify V˙O2max . Results: Supramaximal tests verified V˙O2max in 88% of participants. Group incremental test peak V˙O2 was greater than the supramaximal test (2.27 [0.65] L·min-1 and 2.17 [0.63] L·min-1; P < .001), although both were correlated (r = .94; P < .001). No differences were found in V˙O2 plateau attainment or supramaximal test verification between sex, body mass, or cardiorespiratory fitness groups (all Ps > .18). Supramaximal test time to exhaustion predicted supramaximal test V˙O2max verification (P = .04). Primary and secondary objective criteria had insufficient sensitivity (7.1%-24.1%) and specificity (50%-100%) to verify V˙O2max . Conclusion: The utility of supramaximal testing to verify V˙O2max is not affected by sex, body mass, or cardiorespiratory fitness status. Supramaximal testing should replace secondary objective criteria to verify V˙O2max .
Step test
Cycle ergometer
Incremental exercise
Fitness test
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This study analyzed the effects of an individualized and progressive multicomponent exercise program on blood pressure, cardiorespiratory fitness, and body composition in long-term care residents. This was a single-blind, multicenter, randomized controlled trial performed in 10 long-term care settings and involved 112 participants. Participants were randomly assigned to a control group or an intervention group. The control group participated in routine activities; the intervention group participated in a six-month individualized and progressive multicomponent exercise program focused on strength, balance, and walking recommendations. The intervention group maintained peak VO2, oxygen saturation, and resting heart rate, while the control group showed a significant decrease in peak VO2 and oxygen saturation and an increase in resting heart rate throughout the six-month period. Individualized and progressive multicomponent exercise programs comprising strength, balance, and walking recommendations appear to be effective in preventing cardiorespiratory fitness decline in older adults living in long-term care settings.
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To determine the concurrent validity and responsiveness of the 6 minute walk test (6-MWT) as a measure of cardiorespiratory fitness in people with fibromyalgia.Subjects completed the 6-MWT, a Fibromyalgia Impact Questionnaire (FIQ), and a peak oxygen consumption (pVO2) exercise test before (n = 28) and after (n = 20) a 12 week exercise program.The correlations between 6-MWT distance and pVO2 before (r = 0.328) and after (r = 0.420) the exercise program were not significant. Significant correlations were obtained between 6-MWT distance and FIQ total (r = -0.494, p < 0.01) and physical impairment (r = -0.403, p < 0.05) scores. Fifteen of 28 subjects completed the exercise program, with significant (p < 0.05) changes in 6-MWT distance (+78 m), pVO2 (+1.8 ml/kg/min), and FIQ total score (-9.9). The change in 6-MWT distance was correlated significantly (p < 0.05) with change in FIQ total score but no change in pVO2.The 6-MWT was not a valid predictor of cardiorespiratory fitness. However, it was sensitive to change and was also significantly related to FIQ total score.
Fibromyalgia syndrome
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SWAIN, D. P., and B. A. FRANKLIN. V̇O2 reserve and the minimal intensity for improving cardiorespiratory fitness. Med. Sci. Sports Exerc., Vol. 34, No. 1, 2002, pp. 152–157. Purpose The American College of Sports Medicine has stated that aerobic training needs to occur at a minimum threshold intensity of 50% V̇O2max for most healthy adults and at 40% V̇O2max for those with a very low initial fitness. Recently, the concept of V̇O2 reserve (%V̇O2R, i.e., a percentage of the difference between maximum and resting V̇O2) has been introduced for prescribing exercise intensity. This analysis was designed to determine the threshold intensity for improving cardiorespiratory fitness expressed as %V̇O2R units. Methods Previous studies in healthy subjects (N = 18) that evaluated the results of training at low-to-moderate intensities (i.e., ≤ 60% V̇O2max) were identified. The original studies described the intensity of exercise variously as %V̇O2max, %HRR, %HRmax, or as a specific HR value. In each case, the intensity was translated into %V̇O2R units. Results Exercise training intensities below approximately 45% V̇O2R were consistently ineffective at increasing V̇O2max in studies that used subjects with mean initial V̇O2max values > 40 mL·min−1·kg−1. In studies using subjects with mean initial V̇O2max values < 40 mL·min−1·kg−1, no intensity was found to be ineffective. For this latter group of subjects, the lowest intensities examined were approximately 30% V̇O2R. Conclusion Although evidence for a threshold intensity was not strong, this analysis of training studies supports the use of 45% V̇O2R as a minimal effective training intensity for higher fit subjects and 30% V̇O2R for lower fit subjects.
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Aerobic Exercise
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Sports medicine
Ventilatory threshold
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The aim of this study was to determine the efficacy of Pilates exercise on health related fitness among overweight women. To achieve the purpose of the study thirty six overweight women were randomly selected as subjects and their age ranged between 30 to 35 years. They were divided into two groups. Group I acted as Pilates Exercise group (n=18), and Group II acted as control group (n=18). The experimental groups participated in the Pilates Exercise three days per week for a period of ten weeks. The subjects of the control group participated on their routine activities. To assess the cardiorespiratory fitness used Queens College step test and to measure Hip Range of Motionsit-and-reach test were used. The pre and post-test were conducted on cardiorespiratory endurance and flexibility of both experimental and control groups. The collected data were analyzed by using analysis of covariance (ANCOVA). The results revealed that there was a significant improvement on Maximal Oxygen Uptake and Hip Range of Motion. It was concluded that Pilates exercise is produced greater impact on Maximal Oxygen Uptake and Hip Range of Motion among Middle aged Women.
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ABSTRACT Measuring cardiorespiratory fitness (CF) is important for researchers, clinicians, and exercise practitioners to assess an individual's CF. One method of assessing CF is accomplished by measuring the maximal oxygen uptake during a personalized maximal graded exercise test (GXT). Tailoring a GXT protocol to a specific subject can be troublesome and time-consuming. In this article, simple and ready-to-use spreadsheets allowing the creation of individualized walking, running, and cycling GXT protocols are presented and explained. The procedures within the spreadsheets are based on the latest validated protocols, and the spreadsheets represent a time-saving, practical, and useful tool.
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Purpose: The aim of this study was to compare the widely used accelerometer activity cut-points derived from the absolute moderate intensity recommendation (3‒6 METs), with relative intensity cut-points according to maximal cardiorespiratory fitness (46%‒63% V˙O2max) and to individual lactate thresholds (LT1 and LT2) in postmenopausal women. Method: Thirty postmenopausal women performed several exercise tests with measures of heart rate, blood lactate, accelerometer activity counts and oxygen consumption. Individual regressions were developed to derive the accelerometer activity counts at absolute and relative moderate intensity recommendations and at individual LTs. Results: The activity counts calculated at the lower moderate intensity boundary were lower for the absolute 3 METs threshold (2026 ± 808 ct·min−1) compared to relative 46 % V˙O2max intensity threshold (p < .01, ES: 1.95) and LT1 (p < .01, ES: 2.27), which corresponded to 4.6 ± 0.7 METs. The activity counts at the upper moderate intensity boundary were higher for LT2 (7249 ± 2499 ct·min−1) compared to the absolute 6 METs threshold (p < .01, ES: 0.72) and relative 63% V˙O2max intensity threshold (p < .01, ES: 0.55). The interindividual variability in activity counts at relative intensity thresholds was high (CV = 30–34%), and was largely explained by cardiorespiratory fitness level (R2 = ~ 50%). Conclusion: Individually tailored (relative to V˙O2max or submaximal LTs) rather than fixed accelerometer intensity cut-points derived from the classic absolute moderate physical activity intensity (3–6 METs) would result in a more accurate measurement of an individual´s activity levels and reduce the risk of overestimating or underestimating physical activity.
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Exercise intensity
Metabolic equivalent
Exercise physiology
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Patients with hypertrophic cardiomyopathy (HCM) are excluded from high intensity activities due to perceived fear of sudden cardiac death though data from athletes with HCM suggest competitive sport may be safe for some. Low cardiorespiratory fitness in sedentary HCM patients may confer a greater lifetime cardiovascular event risk than exercise per se. While moderate intensity exercise training in patients with HCM modestly increases fitness, high intensity exercise may be superior. PURPOSE: To compare the efficacy of five months of moderate intensity exercise and high intensity exercise training to improve cardiorespiratory fitness (V̇O2max) in patients with HCM. METHODS: Eight patients with HCM (50 ± 7 years, 3 female) were assessed for maximal oxygen uptake (V̇O2max, Douglas Bag method), cardiac output (Q̇c, acetylene rebreathing), and peripheral oxygen extraction (av-O2 diff, Fick equation) before randomization and after 5 months of moderate or high intensity exercise training. Patients completed 3-4 sessions of moderate intensity exercise each week, while the high intensity group also incorporated a weekly interval training session. RESULTS: Five months of moderate intensity exercise increased absolute V̇O2max by 3% and relative V̇O2max by 4%, while high intensity exercise consistently increased absolute V̇O2max by 6% and relative V̇O2max by 5% (Figure). Maximal Q̇c did not change after moderate intensity exercise (+0.0L [95% CI -2.0 to 1.7]) but increased in all three patients after high intensity exercise (+1.2L [95% CI -1.4 to 3.9]), while maximal av-O2 diff remained stable in both groups (moderate intensity: +0.8mL/100mL [95% CI -1.0 to 2.6]; high intensity: -0.5mL/100mL [95% CI -3.6 to 2.7]). CONCLUSION: Preliminary findings show similar increases in cardiorespiratory fitness following five months of moderate and high intensity exercise training in patients with HCM, although improvements were more consistent after high intensity exercise.
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Exercise intensity
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Abstract This study compared ventilation patterns during incremental load tests to exhaustion. Ten endurance trained individuals and eight recreationally active trained individuals underwent a maximal oxygen uptake ( O 2max ) determination test on both a cycle (CE) and treadmill (TM) ergometer. Cardiorespiratory variables O 2 , CO 2 , RER, E , and R ), movement frequency (MF) and entrainment (ENT) were collected and calculated relative to fixed percentages of O 2max (isometabolic), ranging from 60 to 100%. Minute ventilation ( E ) was similar between groups on both ergometers. Concurrently, V T was significantly higher, while R was significantly lower on the CE compared to the TM in both groups ( P <0.05). At isometabolic intensities there were no difference in R or ENT between groups or mode of testing while the endurance trained group reached higher V T values on the CE. Although the endurance trained group reached higher cardiorespiratory values compared to the recreationally active trained group, their ventilatory patterns were similar between modes of testing. These results seem to be dependent on the exercise modality and not necessarily the type of training individuals regularly participate in.
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Ventilatory threshold
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