Maximal Respiratory Exchange Ratio Research Articles

Physiological, Spatiotemporal, Anthropometric, Training, and Performance Characteristics of a 75-Year-Old Multiple World Record Holder Middle-Distance Runner.

This study assessed the cardiorespiratory capacity, anaerobic speed reserve, and anthropometric and spatiotemporal variables of a 75-year-old world-class middle-distance runner who previously obtained several European and world records in the age categories of 60-70years, achieved 13 European titles and 15 world champion titles, and also holds several European records for the 75-year-old category. Heart rate, oxygen uptake, carbon dioxide production, ventilation, step frequency, contact time, and velocity at maximal oxygen uptake (VO2max) were measured during treadmill running. Maximal sprinting speed was assessed during track sprinting and used to compute anaerobic speed reserve. Body fat percentage was assessed using air displacement plethysmography. Body fat percentage was 8.6%, VO2max was 50.5mL·kg-1·min-1, maximal ventilation was 141L·min-1, maximum heart rate was 164beats·min-1, maximum respiratory exchange ratio was 1.18, and velocity at VO2max was 16.7km·h-1. The average stride frequency and contact time during the last 30 seconds of the 4-minute run at 10km·h-1 were 171steps·min-1 and 241ms and 187steps·min-1 and 190ms in the last 40seconds at 17km·h-1, respectively. The anaerobic speed reserve was 11.4km·h-1, corresponding to an anaerobic speed reserve ratio of 1.68. This 75-year-old runner has an exceptionally high VO2max and anaerobic speed reserve ratio. In addition, his resilience to injuries, possibly due to a relatively high volume of easy runs, enabled him to sustain regular training since his 50s and achieve international performance in his age group.

Beta-Adrenergic Receptor Blockade Effects on Cardio-Pulmonary Exercise Testing in Healthy Young Adults: A Randomized, Placebo-Controlled Trial

BackgroundBeta-blockers are increasingly prescribed while the effects of beta-adrenergic receptor blockade on cardio-pulmonary exercise test (CPET)-derived parameters remain under-studied.MethodsTwenty-one young healthy adults repeated three CPET at the same time with an interval of 7 days between each test. The tests were performed 3 h after a random, double-blind, cross-over single-dose intake of placebo, 2.5 mg or 5.0 mg bisoprolol, a cardio-selective beta1-adrenoreceptor antagonist. Gas exchange, heart rate (HR) and blood pressure (BP) were measured at rest and during cyclo-ergometric incremental CPET.ResultsMaximal workload and VO2max were unaffected by the treatment, with maximal respiratory exchange ratio > 1.15 in all tests. A beta-blocker dose-dependent effect reduced resting and maximal BP and HR and the chronotropic response to exercise, evaluated by the HR/VO2 slope (placebo: 2.9 ± 0.4 beat/ml/kg; 2.5 mg bisoprolol: 2.4 ± 0.5 beat/ml/kg; 5.0 mg bisoprolol: 2.3 ± 0.4 beat/ml/kg, p < 0.001). Ventilation efficiency measured by the VE/VCO2 slope and the ventilatory equivalent for CO2 at the ventilatory threshold were not affected by beta1-receptor blockade. Post-exercise chronotropic recovery measured after 1 min was enhanced under beta1-blocker (placebo: 26 ± 7 bpm; 2.5 mg bisoprolol: 32 ± 6 bpm; 5.0 mg bisoprolol: 33 ± 6 bpm, p < 0.01).ConclusionThe present results suggest that a single dose of bisoprolol does not affect metabolism, respiratory response and exercise capacity. However, beta-adrenergic blockade dose dependently reduces exercise hemodynamic response by lowering BP and the chronotropic response.

Abstract 11237: Dose Response and Long QT Genotype During Exercise Stress Testing in Children

Introduction: Beta-blockers (BB) are first-line therapy for long QT syndrome (LQTS). Many physicians rely on repeated exercise stress tests (ESTs) to establish the optimal dose in each patient. Hypothesis: Increased BB dose is associated with a decrease in maximum heart rate, influenced by precision-medicine factors including genotype. Methods: Retrospective chart review of treadmill ESTs with the outcome variable “% predicted heart rate (HR)” = (maximum HR achieved/(220-age))*100. Genotype positive patients had pathogenic or likely pathogenic variants, re-adjudicated in 2022. Doses of BB other than nadolol were converted to nadolol equivalents using an established methodology. Results: We evaluated 345 ESTs in 132 LQTS patients (58% genotype positive) from 2003-21. The mean age at first EST was 12.5 years (standard deviation 4.0 years). Most patients were prescribed nadolol (59%) or atenolol (28%). When controlled for person-level fixed effects, we observed an inverse relationship between BB dose and % predicted HR. The dose-response slope was steeper in genotype positive patients than genotype negative patients (-4.8 vs. -3.3, Figure , p&lt;0.01). We observed mild decreases in blood pressure as BB dose increased, (mean 5 mmHg decrease in systolic blood pressure per 1 mg/kg increase in BB). However, neither maximum VO2 nor maximum respiratory exchange ratio were affected by increased BB dose (the slope of each was indistinguishable from 0 in person-level fixed effects models). Conclusion: In children with LQTS, genotype positive patients were more sensitive to BB than genotype negative patients. We developed a multivariate model to predict the dose of BB required to achieve therapeutic beta-blockade, conditional on individual patient demographics and genotype. The model may decrease the need for serial ESTs. BB dose did not affect maximum VO2 or respiratory exchange ratio, which is reassuring for children and adolescents with LQTS who exercise.

A Comparison of Warm-Up Effects on Maximal Aerobic Exercise Performance in Children.

The aim of this study was to compare the warm-up effects of treadmill walking (TW) with a dynamic (DY) bodyweight warm-up on maximal aerobic exercise performance in children. Sixteen children (10.9 ± 1.5 vrs) were tested for peak oxygen uptake (VO2 peak) on 2 nonconsecutive days following different 6 min warm-up protocols. TW consisted of walking on a motor-driven treadmill at 2.2 mph and 0% grade whereas the DY warm-up consisted of 9 body weight movements including dynamic stretches, lunges, and jumps. Maximal heart rate was significantly higher following DY than TW (193.9 ± 6.2 vs. 191.6 ± 6.1 bpm, respectively; p = 0.008). VO2 peak (54.8 ± 9.6 vs. 51.8 ± 8.7 mL/kg/min; p = 0.09), maximal minute ventilation (68.9 ± 14.8 vs. 64.9 ± 9.4 L/min; p = 0.27), maximal respiratory exchange ratio (1.12 ± 0.1 vs. 1.11 ± 0.1; p = 0.85) and total exercise time (614.0 ± 77.1 vs. 605 ± 95.0 s; p = 0.55) did not differ significantly between DY and TM warm-ups, respectively. These findings indicate that the design of the warm-up protocol can influence the heart rate response to maximal aerobic exercise and has a tendency to influence VO2 peak. A DY warm-up could be a viable alternative to a TW warm-up prior to maximal exercise testing in children.

Comparison of VO2peak from the Progressive Aerobic Cardiovascular Endurance Run (PACER) and treadmill in children

Background/ObjectivesThe purpose of this study was to investigate the difference in peak oxygen consumption (VO2peak) during a graded treadmill test and the Progressive Aerobic Cardiovascular Endurance Run (PACER) in a sample of 7–14 year old children. MethodsForty-four participants (25 boys, 19 girls) had VO2 assessed during a peak treadmill test and the PACER by a portable indirect calorimeter on non-consecutive days. Exercise parameters were compared between exercise tests by paired t-tests. ResultsThe PACER elicited a greater measured VO2peak (49.4 ± 9.4 vs. 46.7 ± 7.5 ml. kg−1·min−1) and maximum respiratory exchange ratio (1.14 ± 0.08 vs. 1.07 ± 0.08) than the treadmill test (p < 0.05). Rating of perceived exertion was higher (8.1 ± 3.5 vs 7.6 ± 3.8) during the treadmill test compared to the PACER test (p < 0.05). There was no difference in maximum heart rate between treadmill test and PACER test (196.9 ± 9.3 vs. 198.6 ± 8.8, p > 0.05). ConclusionsThe PACER provides an acceptable measure of cardiorespiratory fitness in children but the finding that children elicit a higher measured VO2peak during the PACER compared to a graded treadmill test warrants continual refinement in future aerobic fitness prediction equations from the PACER.

Correlation of maximal respiratory exchange ratio with anaerobic power and maximal oxygen uptake in anaerobic trained athletes

Background and Study Aim. The respiratory exchange ratio (RER) is the ratio of the amount of carbon dioxide produced (VCO2) to the amount of oxygen uptake (VO2) is important. It indirectly informs about the predominant metabolic pathway to provide the energy needed during exercise. The relationship of maximal RER with aerobic and anaerobic capacity in athletes remains unclear. The purpose of this study was to investigate the relationship between maximal RER and anaerobic power and maximal oxygen uptake (VO2max) in anaerobic trained athletes.&#x0D; Material and Methods. Thirteen male alpine skiers (age 18.1 ± 3.1 years) competing in national and international competitions participated in the study. Athletes first performed an incremental treadmill run test to determine their VO2max (ml/kg/min), maximal RER (VCO2 / VO2) and maximal running speed (km/h). After 48 hours, the athletes performed the Wingate anaerobic test to determine peak power, mean power, minimum power, and fatigue index. Pearson correlation coefficients were used to examine the relations between variables.&#x0D; Results. Maximal RER was positively correlated with peak power (r = 0.587, p &lt; 0.035), mean power (r = 0.656, p &lt; 0.015) and minimum power (r = 0.674, p &lt; 0.012). Maximal RER did not significantly correlate with fatigue index (p &gt; 0.05). Maximal RER was negatively correlated with the VO2max (r = – 0.705, p &lt; 0.007) and maximal running speed (r = – 0.687, p &lt; 0.01).&#x0D; Conclusions. Maximal RER may be useful for evaluating anaerobic capacity in anaerobic-trained athletes. Measuring the maximal RER values of athletes during incremental exercise may provide information about physiological adaptations in response to physical training.

Exercise Fat Oxidation Is Positively Associated with Body Fatness in Men with Obesity: Defying the Metabolic Flexibility Paradigm.

Obesity is thought to be associated with a reduced capacity to increase fat oxidation in response to physical exercise; however, scientific evidence supporting this paradigm remains scarce. This study aimed to determine the interrelationship of different submaximal exercise metabolic flexibility (Metflex) markers and define its association with body fatness on subjects with obesity. Twenty-one male subjects with obesity performed a graded-intensity exercise protocol (Test 1) during which cardiorespiratory fitness (CRF), maximal fat oxidation (MFO) and its corresponding exercise intensity (FATmax) were recorded. A week afterward, each subject performed a 60-min walk (treadmill) at FATmax (Test 2), and the resulting fat oxidation area under the curve (TFO) and maximum respiratory exchange ratio (RERpeak) were recorded. Blood lactate (LAb) levels was measured during both exercise protocols. Linear regression analysis was used to study the interrelationship of exercise Metflex markers. Pearson’s correlation was used to evaluate all possible linear relationships between Metflex and anthropometric measurement, controlling for CRF). The MFO explained 38% and 46% of RERpeak and TFO’s associated variance (p < 0.01) while TFO and RERpeak were inversely related (R2 = 0.54, p < 0.01). Body fatness positively correlated with MFO (r = 0.64, p < 0.01) and TFO (r = 0.63, p < 0.01) but inversely related with RERpeak (r = −0.67, p < 0.01). This study shows that MFO and RERpeak are valid indicators of TFO during steady-state exercise at FATmax. The fat oxidation capacity is directly associated with body fatness in males with obesity.

The effects of soccer training in aerobic capacity between trained and untrained adolescent boys of the same biological age.

The purpose of this study was to examine the effects of soccer training on maximal oxygen uptake and anthropometric characteristics in different ages of soccer players and untrained adolescents of the same biological age. A total of one hundred and twenty-six (N.=126) young soccer players and untrained boys throughout the developmental ages of 12 (soccer players N.=22; untrained boys = 22) 14 (soccer players N.=20; untrained boys = 18) and 16 (soccer players N.=22; untrained boys = 22) volunteered to participate in the study. Sexual maturation was classified according to Tanner's stages. Soccer players participated both in their school's physical education program and in a soccer training program, while the untrained participated only in their school's physical education program. All participants underwent anthropometric measurements and performed a maximal exercise test on a motor driven treadmill to determine maximal oxygen uptake (V̇O2<inf>max</inf>) and cardiorespiratory indices. Blood lactate (BL) concentration was determined in the 5th minute of recovery using a lactate photometer. The trained group showed significantly higher V̇O2<inf>max</inf>, in absolute and relative values (P<0.001), BL<inf>max</inf> (P<0.05) and maximal respiratory exchange ratio (RER<inf>max</inf>) (P<0.05) compared to the untrained group. Resting heart rate (HR) and systolic blood pressure were significantly lower (P<0.05) for the trained compared to untrained. The results of this study showed that systematic soccer training has a positive effect in the central cardiovascular system expressed as V̇O2<inf>max</inf>, HR and blood pressure.

Dynamic Warm-up Effects On Maximal Treadmill Exercise Performance In Children: A Pilot Study

Dynamic warm-up protocols (DWP) consisting of moderate- and high-intensity exercise movements have been found to enhance strength and power performance in youth; however, the effects of DWP on maximal treadmill exercise performance in children are unclear. Prior to pediatric exercise testing participants typically perform low-intensity treadmill walking (TW). PURPOSE: To compare the effects of a DWP with a TW warm-up protocol on maximal exercise performance in children. METHODS: 11 healthy children (10.8 ± 1.5 vrs) were tested for peak oxygen uptake (VO2 peak) on 2 nonconsecutive days following different 6 min warm-up protocols performed in random order. DWP consisted of 9 progressive body weight movements including dynamic stretches, lunges, hip bridges, and jumps whereas the TW protocol consisted of walking on a motor-driven treadmill at 2.2 mph and 0% grade. Comparisons between trials were made with a paired t-test. RESULTS: VO2 peak was significantly higher (p=0.04) following DWP than TW (56.9 ± 9.1 vs 52.7 ± 9.4 ml/kg/min) and a trend (p=0.08) towards greater maximal heart rate was noted following DWP vs TW (192.5 ± 7.5 vs 190.9 ± 7.1 bpm, respectively). No significant differences between DWP and TW trials were observed for maximal minute ventilation (70.7 ± 17.5 vs 64.0 ± 10.4 L/min, respectively), maximal respiratory exchange ratio (1.08 ± 0.05 vs 1.08 ± 0.07, respectively) and total exercise test time (640.9 ± 77.8 vs 638.0 ± 97.4 sec, respectively). No order effects between test day 1 and test day 2 were observed for any variable. CONCLUSIONS: These findings indicate that the design of the warm-up protocol can influence the cardiopulmonary responses to maximal treadmill exercise and that a DWP can result in a higher VO2 peak than a low intensity TW protocol in healthy children.

Overshoot Of The Respiratory Exchange Ratio During Recovery From Maximal Exercise In Kidney Transplant Recipients

PURPOSE: The overshoot of the respiratory exchange ratio (RER) during recovery from maximal cardiopulmonary exercise testing (CPET) has been found reduced in magnitude among patients with heart failure, possibly due to the slow recovery kinetics of VO2. To investigate whether this phenomenon could be present also in patients with peripheral limitations to exercise, a population of kidney transplant recipients (KTRs) was specifically studied, since these patients may present peripheral alterations at the muscular and microvascular level. METHODS: RER was retrospectively evaluated during recovery after maximal exercise (peak RER > 1.1) in KTRs without history of systolic dysfunction that underwent CPET for clinical purposes. Variables assessed were the maximum RER during recovery (RER-max), the RER overshoot magnitude (RER-OM: (RER-max - peak RER) / peak RER %) and the time from peak RER to RER-max. Patients signed informed consent. RESULTS: 57 KTRs were included in the study (28% females). The median value of peak RER was 1.2 (IQR 0.1). Mean RER-max and RER-OM were 1.6 ± 0.2 and 28.4 ± 12.7%, respectively. The time to reach RER-max was on average 131.4 ± 42.8 s. RER-OM showed significant correlations with peak VO2 (ρ =0.57; P<0.01), VO2 at the anaerobic threshold (r=0.44; P<0.01), VE/VCO2 slope (r=-0.32; P<0.05) and oxygen uptake efficiency slope (r=0.48; P<0.01). RER-max showed comparable correlations with these parameters, however, conversely to RER-OM, it was conditioned by peak RER (ρ=0.50; P<0.01). Finally, RER-OM was found significantly different among sub-populations of KTRs when stratified by patients’ aerobic capacity (Weber class A vs. B+C: 31.1 ± 12.1% vs. 18.6 ± 9.9%; P<0.01) or ventilatory efficiency (Ventilatory class I vs. II: 30.9 ± 13.3% vs. 23.2 ± 9.6%; P=0.03). CONCLUSIONS: This is the first study in KTRs investigating the recovery of RER, which seems to be affected by patients’ cardiorespiratory fitness. The present data showed that the RER-OM values of this population are similar to normal subjects’ values reported in literature. Moreover, RER-OM appears as a valuable parameter to assess the recovery of RER, being independent from peak RER and directly correlated to other prognostic CPET parameters.

Ratings of Perceived Exertion During Walking Predicts Endurance Independent of Physiological Effort in Older Women.

Hunter, GR, Neumeier, WH, Chandler-Laney, PC, Carter, SJ, Borges, JH, Hornbuckle, LM, Plaisance, EP, and Fisher, G. Ratings of perceived exertion during walking predicts endurance independent of physiological effort in older women. J Strength Cond Res 34(5): 1340-1344, 2020-This study aimed to determine whether ratings of perceived exertion (RPE) and physiological effort at different exercise intensities relate to exercise endurance. Ninety-eight sedentary women (older than 60 years) completed 3 submaximal locomotion tasks: (a) stair climbing, (b) flat walking at 2 mph, and (c) grade walking at 2 mph. Maximal treadmill endurance was measured at least 3 days before the submaximal tests. Oxygen uptake was measured during all tests, and RPE were collected for the submaximal tasks. Ratings of perceived exertion during moderate-intensity exercise (walking on the flat at 43% V[Combining Dot Above]O2max, partial R = -0.35, p < 0.01), but not higher intensity exercise (grade walk at 59% V[Combining Dot Above]O2max, p = 0.49, and stair climbing at 67% V[Combining Dot Above]O2max, p = 0.17), were related to endurance even after adjusting for aerobic capacity and physiological effort (composite of maximal heart rate, ventilation, and respiratory exchange ratio). However, physiological effort was significantly related to endurance for the higher intensity exercise (both grade walk and stair climbing partial R >-0.24, p < 0.02). Similar to previous findings that subjective ratings of fatigue at rest were related to RPE during low/moderate-intensity exercise, but not higher intensity exercise, these data further support Ekkekakis's dual-mode hypothesis that cognitive factors influence RPE during low/moderate-intensity exercise. A practical application is that the coach and personal trainer should know that physiological effort seems to play a greater role in influencing endurance than RPE as intensity of exercise increases.

New Data-based Cutoffs for Maximal Exercise Criteria across the Lifespan.

To determine age-dependent cutoff values for secondary exhaustion criteria for a general population free of exercise limiting chronic conditions; to describe the percentage of participants reaching commonly used exhaustion criteria during a cardiopulmonary exercise test (CPET); and to analyze their oxygen uptake at the respective criteria to quantify the impact of a given criterion on the respective oxygen uptake (V˙O2) values. Data from the COmPLETE-Health Study were analyzed involving participants from 20 to 91 yr of age. All underwent a CPET to maximal voluntary exertion using a cycle ergometer. To determine new exhaustion criteria, based on maximal respiratory exchange ratio (RERmax) and age-predicted maximal HR (APMHR), one-sided lower tolerance intervals for the tests confirming V˙O2 plateau status were calculated using a confidence level of 95% and a coverage of 90%. A total of 274 men and 252 women participated in the study. Participants were nearly equally distributed across age decades from 20 to >80 yr. A V˙O2 plateau was present in 32%. There were only minor differences in secondary exhaustion criteria between participants exhibiting a V˙O2 plateau and participants not showing a V˙O2 plateau. New exhaustion criteria according to the tolerance intervals for the age group of 20 to 39 yr were: RERmax ≥ 1.13, APMHR210 - age ≥ 96%, and APMHR208 × 0.7 age ≥ 93%; for the age group of 40 to 59 yr: RERmax ≥ 1.10, APMHR210 - age ≥ 99%, and APMHR208 × 0.7 age ≥ 92%; and, for the age group of 60 to 69 yr: RERmax ≥ 1.06, APMHR210 - age ≥ 99%, and APMHR208 × 0.7 age ≥ 89%. The proposed cutoff values for secondary criteria reduce the risk of underestimating V˙O2max. Lower values would increase false-positive results, assuming participants are exhausted although, in fact, they are not.

Vigorous cool room treadmill training to improve walking ability in people with multiple sclerosis who use ambulatory assistive devices: a feasibility study

BackgroundAerobic training has the potential to restore function, stimulate brain repair, and reduce inflammation in people with Multiple Sclerosis (MS). However, disability, fatigue, and heat sensitivity are major barriers to exercise for people with MS. We aimed to determine the feasibility of conducting vigorous harness-supported treadmill training in a room cooled to 16 °C (10 weeks; 3times/week) and examine the longer-term effects on markers of function, brain repair, and inflammation among those using ambulatory aids.MethodsTen participants (9 females) aged 29 to 74 years with an Expanded Disability Status Scale ranging from 6 to 7 underwent training (40 to 65% heart rate reserve) starting at 80% self-selected walking speed. Feasibility of conducting vigorous training was assessed using a checklist, which included attendance rates, number of missed appointments, reasons for not attending, adverse events, safety hazards during training, reasons for dropout, tolerance to training load, subjective reporting of symptom worsening during and after exercise, and physiological responses to exercise. Functional outcomes were assessed before, after, and 3 months after training. Walking ability was measured using Timed 25 Foot Walk test and on an instrumented walkway at both fast and self-selected speeds. Fatigue was measured using fatigue/energy/vitality sub-scale of 36-Item Short-Form (SF-36) Health Survey, Fatigue Severity Scale, modified Fatigue Impact Scale. Aerobic fitness (maximal oxygen consumption) was measured using maximal graded exercise test (GXT). Quality-of-life was measured using SF-36 Health Survey. Serum levels of neurotrophin (brain-derived neurotrophic factor) and cytokine (interleukin-6) were assessed before and after GXT.ResultsEight of the ten participants completed training (attendance rates ≥ 80%). No adverse events were observed. Fast walking speed (cm/s), gait quality (double-support (%)) while walking at self-selected speed, fatigue (modified Fatigue Impact Scale), fitness (maximal workload achieved during GXT), and quality-of-life (physical functioning sub-scale of SF-36) improved significantly after training, and improvements were sustained after 3-months. Improvements in fitness (maximal respiratory exchange ratio and maximal oxygen consumption during GXT) were associated with increased brain-derived neurotrophic factor and decreased interleukin-6.ConclusionVigorous cool room training is feasible and can potentially improve walking, fatigue, fitness, and quality-of-life among people with moderate to severe MS-related disability.Trial registrationThe study was approved by the Newfoundland and Labrador Health Research Ethics Board (reference number: 2018.088) on 11/07/2018 prior to the enrollment of first participant (retrospectively registered at ClinicalTrials.gov: NCT04066972. Registered on 26 August 2019.

Maximal oxygen uptake and concentric isokinetic muscle strength in pubertal football trained and untrained boys of the same biological age

The purpose of the present study was to examine the effects of long term (prolonged) football training on maximal oxygen uptake (VO2) and isokinetic muscle strength in young football players and untrained boys of the same biological age. Twenty football competitive boys (mean age 14 ± 0 yrs; height 165.5 ± 8.5 cm; weight 59.9 ± 9.5 kg; years of training 7 ± 3) and eighteen untrained school boys (mean age 14 ± 0; height 168.22 ± 10.46 cm; weight 59.3 ± 9.9 kg) of the same biological age volunteered to participate in the study. Sexual maturation classified according to Tanner’s stage 3. The football players participated both in their school’s physical education program and in their football team training program while the untrained group participated only in their school’s physical education program (2–3 times per week for 40 min). All subjects were tested for maximal oxygen uptake (VO2) and respiratory exchange ratio (RER) on the treadmill using an open circuit spirometry. The isokinetic peak torque values of quadriceps (Q) and hamstrings (H) as well as the H : Q strength ratios were recorded. Hcon : Qcon was calculated as the ratio of the peak concentric torque of H to the peak concentric torque of the Q. Results showed that the trained group had significantly lower heart rate in rest (p < 0.001), higher RER (p < 0.001), maximal blood lactate (BLmax) (p < 0.001) and higher VO2 max in both relative and absolute values (p < 0.001) compared to the untrained group. At angular velocities of 60 ° s−1 and 180 ° s−1 the relative peak torque of Q and H were significantly higher (Q = p < 0.01; H = p < 0.01). However, the absolute values of Q and H as well as the H : Q ratios at all angular velocities did not differ significantly between the two groups. The results suggest that systematic football training (intensity and duration) has a positive effect in metabolic capacity, cardiorespiratory system and neuromuscular function.

Impact of Bariatric Surgery on Women Aerobic Exercise Capacity

Bariatric surgery has a considerable positive effect on weight loss and on metabolic and cardiovascular risks. It has therefore been extensively used this last decade to overcome obesity. However, the impact of this surgery on exercise capacity remains unclear. The aim of this study is to clarify the impact of a surgically induced weight loss on aerobic exercise capacity (VO2max) in a specific middle-aged female population. Forty-two women with a body mass index > 40kg/m2 (age, 42 ± 13years; weight, 117 ± 15kg) underwent blood analyses and a cardiopulmonary exercise test (CPET) before and 1year after bariatric surgery. CPET was performed on a cycloergometer. The first ventilatory threshold (VT1) was measured according to the V-slope method. Absolute VO2max was reduced by 10% after surgery (2.0 ± 0.4 vs 1.8 ± 0.4l/min, p< 0.01) or increased when corrected for body weight (18 ± 4 vs 23 ± 4l/min/kg, p< 0.001) or unchanged when expressed as percentage of predicted values (111 ± 21 vs 105 ± 22, p= 0.06). Weight loss did not affect ventilatory or chronotropic response but increased maximal respiratory exchange ratio (RER) (p< 0.001), decreased maximal O2pulse (p< 0.05) and VT1 in milliliters per minute (p< 0.01). By multivariable analysis, decreased absolute VO2max after weight loss was associated with increased maximal RER and reduced maximal O2pulse (p< 0.05, p< 0.01 respectively), possibly related to a muscular mass limitation. Weight loss induced by bariatric surgery may reduce aerobic capacity in women in relation to muscle mass loss.

Reliability and Validity of Swimming Flume Protocol to Measure Maximal Aerobic Power of Healthy Adults

A modality specific swimming protocol to assess maximal aerobic power (MAP) is essential to accurately quantify swimming training and performance. A graded intensity MAP swimming protocol executed in a swimming flume controls swimming speed (i.e. velocity), and may facilitate kinematic and metabolic assessments. PURPOSE: To assess: 1) reliability of a swimming flume maximal oxygen consumption (VO2maxfl)(i.e. MAP) protocol; and 2) validity of a VO2maxfl protocol using a swimming pool performance swim (PS) test as the criterion. METHODS: Nineteen healthy males (n=9) and females (n=10) (age, 28.5 ± 8.3 yrs; height, 174.7 ± 8.2 cm; weight, 72.9 ± 12.5 kg; %body fat, 21.4 ± 5.9) performed two swimming flume VO2maxfl tests (VO2maxfl A and VO2maxfl B), and one PS test [500 meters (444.7 ± 139.4 seconds)]. Test-retest reliability of VO2maxfl (ml·kg-1·min-1),HRmax (b·min-1), cardiorespiratory efficiency (O2 pulse; VO2max /HRmax), maximal respiratory exchange ratio (RERmax), ventilation (Vemax) (L·min-1), and PS test time was assessed by ICC’s (2,1). Test validity was determined by correlating VO2maxflA with the PS using Pearson’s coefficients. RESULTS: Intra-subject reliability (ICC) for cardiorespiratory responses during the VO2maxflA and VO2maxflB tests are presented in Table 1. For validity, a moderate correlation was found between VO2maxflA and 500 PS (r =-0.478; p<0.05). CONCLUSIONS: The VO2maxfl test employed presently is a reliable and functionally valid assessment of MAP. It is proposed that a swimming flume-based protocol to measure MAP will facilitate mode specific comparisons of test responses with performance outcomes for military, clinical, or athletic populations.Table 1

Reference Standards for Cardiorespiratory Fitness Measured With Cardiopulmonary Exercise Testing Using Cycle Ergometry: Data From the Fitness Registry and the Importance of Exercise National Database (FRIEND) Registry

The importance of cardiorespiratory fitness (CRF) is well established. This report provides newly developed standards for CRF reference values derived from cardiopulmonary exercise testing (CPX) using cycle ergometry in the United States. Ten laboratories in the United States experienced in CPX administration with established quality control procedures contributed to the “Fitness Registry and the Importance of Exercise: A National Database” (FRIEND) Registry from April 2014 through May 2016. Data from 4494 maximal (respiratory exchange ratio, ≥1.1) cycle ergometer tests from men and women (20-79 years) from 27 states, without cardiovascular disease, were used to develop these references values. Percentiles of maximum oxygen consumption (VO2max) for men and women were determined for each decade from age 20 years through age 79 years. Comparisons of VO2max were made to reference data established with CPX data from treadmill data in the FRIEND Registry and previously published reports. As expected, there were significant differences between sex and age groups for VO2max (P<.01). For cycle tests within the FRIEND Registry, the 50th percentile VO2max of men and women aged 20 to 29 years declined from 41.9 and 31.0 mLO2/kg/min to 19.5 and 14.8 mLO2/kg/min for ages 70 to 79 years, respectively. The rate of decline in this cohort was approximately 10% per decade. The FRIEND Registry reference data will be useful in providing more accurate interpretations for the US population of CPX-measured VO2max from exercise tests using cycle ergometry compared with previous approaches based on estimations of standard differences from treadmill testing reference values.

Effects of body position on exercise capacity and pulmonary vascular pressure-flow relationships.

There has been revival of interest in exercise testing of the pulmonary circulation for the diagnosis of pulmonary vascular disease, but there still is uncertainty about body position and the most relevant measurements. Doppler echocardiography pulmonary hemodynamic measurements were performed at progressively increased workloads in 26 healthy adult volunteers in supine, semirecumbent, and upright positions that were randomly assigned at 24-h intervals. Mean pulmonary artery pressure (mPAP) was estimated from the maximum tricuspid regurgitation jet velocity. Cardiac output was calculated from the left ventricular outflow velocity-time integral. Pulmonary vascular distensibility α-index, the percent change of vessel diameter per millimeter mercury of mPAP, was calculated from multipoint mPAP-cardiac output plots. Body position did not affect maximum oxygen uptake (Vo2max), maximum respiratory exchange ratio, ventilatory equivalent for carbon dioxide, or slope of mPAP-cardiac output relationships, which was on average of 1.5 ± 0.4 mmHg·l-1·min-1 Maximum mPAP, cardiac output, and total pulmonary vascular resistance were, respectively, 34 ± 4 mmHg, 18 ± 3 l/min, and 1.9 ± 0.3 Wood units. However, the semirecumbent position was associated with a 10% decrease in maximum workload. Furthermore, cardiac output-workload or cardiac output-Vo2 relationships were nonlinear and variable. These results suggest that body position does not affect maximum exercise testing of the pulmonary circulation when results are expressed as mPAP-cardiac output or maximum total pulmonary vascular resistance. Maximum workload is decreased in semirecumbent compared with upright exercise. Workload or Vo2 cannot reliably be used as surrogates for cardiac output.

Exercise capacity is not impaired after acute alcohol ingestion: a pilot study.

The usage of alcohol is widespread, but the effects of acute alcohol ingestion on exercise performance and the stress hormone axis are not fully elucidated.We studied 10 healthy white men, nonhabitual drinkers, by Doppler echocardiography at rest, spirometry, and maximal cardiopulmonary exercise test (CPET) in two visits (2-4 days in between), one after administration of 1.5 g/kg ethanol (whisky) diluted at 15% in water, and the other after administration of an equivalent volume of water. Plasma levels of NT-pro-BNP, cortisol, and adrenocorticotropic hormone (ACTH) were also measured 10 min before the test, at maximal effort and at the third minute of recovery. Ethanol concentration was measured from resting blood samples by gas chromatography and it increased from 0.00 ± 0.00 to 1.25 ± 0.54‰ (P < 0.001). Basal echocardiographic and spirometric parameters were normal and remained so after acute alcohol intake, whereas ACTH, cortisol, and NT-pro-BNP nonsignificantly increased in all phases of the test. CPET data suggested a trend toward a slight reduction of exercise performance (peak VO2 = 3008 ± 638 vs. 2900 ± 543 ml/min, ns; peak workload = 269 ± 53 vs. 249 ± 40 W, ns; test duration 13.7 ± 2.2 vs. 13.3 ± 1.7 min, ns; VE/VCO2 22.1 ± 1.4 vs. 23.3 ± 2.9, ns). Ventilatory equivalent for carbon dioxide at rest was higher after alcohol intake (28 ± 2.5 vs. 30.4 ± 3.2, P = 0.039) and maximal respiratory exchange ratio was lower after alcohol intake (1.17 ± 0.02 vs. 1.14 ± 0.04, P = 0.04). In conclusion, we showed that acute alcohol intake in healthy white men is associated with a nonsignificant exercise performance reduction and stress hormone stimulation, with an unchanged exercise metabolism.

The Angiotensin Converting Enzyme Insertion/Deletion Polymorphism Modifies Exercise-Induced Muscle Metabolism.

ObjectiveA silencer region (I-allele) within intron 16 of the gene for the regulator of vascular perfusion, angiotensin-converting enzyme (ACE), is implicated in phenotypic variation of aerobic fitness and the development of type II diabetes. We hypothesised that the reportedly lower aerobic performance in non-carriers compared to carriers of the ACE I-allele, i.e. ACE-DD vs. ACE-ID/ACE-II genotype, is associated with alterations in activity-induced glucose metabolism and capillarisation in exercise muscle.MethodsFifty-three, not-specifically trained Caucasian men carried out a one-legged bout of cycling exercise to exhaustion and/or participated in a marathon, the aim being to identify and validate genotype effects on exercise metabolism. Respiratory exchange ratio (RER), serum glucose and lipid concentration, glycogen, and metabolite content in vastus lateralis muscle based on ultra-performance lipid chromatography-mass spectrometry (UPLC-MS), were assessed before and after the cycling exercise in thirty-three participants. Serum metabolites were measured in forty subjects that completed the marathon. Genotype effects were assessed post-hoc.ResultsCycling exercise reduced muscle glycogen concentration and this tended to be affected by the ACE I-allele (p = 0.09). The ACE-DD genotype showed a lower maximal RER and a selective increase in serum glucose concentration after exercise compared to ACE-ID and ACE-II genotypes (+24% vs. +2% and –3%, respectively). Major metabolites of mitochondrial metabolism (i.e. phosphoenol pyruvate, nicotinamide adenine dinucleotide phosphate, L-Aspartic acid, glutathione) were selectively affected in vastus lateralis muscle by exercise in the ACE-DD genotype. Capillary-to-fibre ratio was 24%-lower in the ACE-DD genotype. Individuals with the ACE-DD genotype demonstrated an abnormal increase in serum glucose to 7.7 mM after the marathon.ConclusionThe observations imply a genetically modulated role for ACE in control of glucose import and oxidation in working skeletal muscle. ACE-DD genotypes thereby transit into a pre-diabetic state with exhaustive exercise, which relates to a lowered muscle capillarisation, and deregulation of mitochondria-associated metabolism.