Incremental Cycle Ergometer Test Research Articles

The oxygen uptake efficiency slope does not accurately predict O2peak of children - the Arkansas Active Kids study.

Cardiorespiratory fitness (CRF) is a vital indicator of health. However, accurately measuring peak oxygen consumption ( O2peak) to determine CRF in children can be challenging. The oxygen uptake efficiency slope (OUES) has been proposed as an alternative metric for predicting O2peak in children, but its accuracy and agreement with measured O2peak remain unclear. A post hoc analysis was conducted in 94 children (ages 7-10years) who completed an incremental cycle ergometer test to measure O2peak. Body composition (Dual-energy X-ray absorptiometry) was measured, and fat mass index (FMI, kg/m2) and fat-free mass index (FFMI, kg/m2) were calculated. OUES was determined using all respiratory data (OUES100%) collected during the cycle ergometer test and using data only up to 60% of heart rate reserve (OUES60%HRR). Regression equations to predict O2peak (Pred- O2peak) were derived from simple and multiple linear regression analysis. Bland-Altman analysis assessed the level of agreement between Pred- O2peak and measured O2peak. OUES60%HRR (β = 0.46, p < 0.0001), age (β = 56.0, p = 0.0004), White race (β = 173.3, p < 0.0003), FFMI (β = 0.98.6, p < 0.000), and FMI (β = -0.40.8, p < 0.000) were retained in the final model. The difference between measured O2peak and Pred- O2peak was not different from zero (p = 0.999). There was a positive association between the difference of measured O2peak and Pred- O2peak and the average of the two methods (β = 0.79, p = 0.0028). There was no mean bias between measured O2peak and Pred- O2peak. However, magnitude bias was present even after considering other significant predictors of O2peak (FMI, FFMI, race, and age) in the regression equation. Caution is advised when using OUES to predict O2peak in children.

CAN DARK CHOCOLATE ACUTE SUPPLEMENTATION IMPROVE CYCLOERGOMETER PERFORMANCE TEST?

Prevalence studies of dark chocolate may produce results similar to those observed after resistance exercise. The results examining the effects of dark chocolate ingestion on aerobic exercise performance are controversial. In addition, there is a choice in experiments with chronically consumed chocolate components (40 to 80 g) and large amounts of dark chocolate in studies to improve athletic performance. Therefore, the purpose of this study to verify the effect of acute supplementation of 80 g dark chocolate (70% cocoa) on performance on cycle ergometer test. Eleven healthy, physically active, but untrained men participated in the study. Two incremental cycle ergometer tests were performed to determine the peak power output (Ppeak) without chocolate supplementation (control condition, C) and with supplementation of 80 g of dark chocolate 70% cocoa (C70%) ingested orally two hours before the test. Variables such as heart rate (HR), blood glucose concentration [GLI], blood pressure (SBP/DBP), and rating of perceived exertion (RPE) were monitored. Data normality was verified by the Shapiro-Wilk test, and the results are presented as mean ± standard deviation (SD). The performance data of the tests and physiological variables were compared using Student's t-test for paired samples, adopting a significance level of P &lt; 0.05. No statistical differences were found for Ppeak (238.0 ± 35.1 vs 250.9 ± 42.7 W) between conditions (C and C70%, respectively), as well as in the other variables. Therefore, we concluded that although the ingestion of 80 g of dark chocolate (70% cocoa) 2 hours prior the cycle ergometer test did not modify the peak power output, physiological and psychophysiological variables analyzed when presenting the average results, individual analysis demonstrated that this supplementation could be used to enhance peak power, which support individual as opposed to group analysis to evaluate performance responses to supplementation protocols.

Greater Relative First and Second Lactate Thresholds in Females Compared With Males: Consideration for Exercise Prescription.

To investigate differences between females and males at lactate thresholds 1 (LT1) and 2 (LT2). Twenty-four female and twenty male participants performed an incremental cycle-ergometer test until exhaustion, where LT1 and LT2 were determined in each volunteer. Power output at LT1 and LT2 was lower in females than in males (P < .001). In addition, power output relative to peak power was higher in females at LT1 and LT2 (P < .001). However, heart rate was higher in females than males at LT1 and LT2 (P = .008). Furthermore, the heart rate relative to maximal heart rate was higher in females compared with males at LT1 and LT2 (P = .002). Females and males may be in a different metabolic situation at the same percentage of maximum. This study helps to reduce sex bias in science, and future guidelines should consider establishing exercise prescription recommendations according to sex. NCT06104150.

Heart Rate Reserve and VO2 Reserve Are Not Interchangeable During Prolonged Exercise

Abstract Background Percentages of heart rate reserve (%HRR) and oxygen consumption reserve (%VO2R) provide equivalent intensities during incremental exercise. These percentages increase during prolonged exercise at a constant workload, and it is unclear if they increase to a similar degree. In this study, we tested whether %HRR and %VO2R maintain equivalency during prolonged exercise at a constant workload. Methods Fifteen males and 12 females participated in an incremental cycle ergometer test to determine maximum VO2. They then performed 2 prolonged exercise trials, 1 for 30 min at a vigorous-intensity workload corresponding with 60% VO2R, and 1 for 60 min at a moderate-intensity workload of 40% VO2R. HR and VO2 were measured continuously, and %HRR and %VO2R were reported every 5 min. A fan and consumption of cold water were used to minimize heat stress. Results Both %HRR and %VO2R increased during constant-workload exercise (P &amp;lt; 0.001), and %HRR increased significantly more than %VO2R (P &amp;lt; 0.001). Females exhibited greater %HRR than %VO2R beginning at 10 min into both trials (P &amp;lt; 0.05), while %HRR exceeded %VO2R for males beginning at 15 min of the 30-min trial (P &amp;lt; 0.05) and at 30 min of the 60-min trial (P &amp;lt; 0.05). HRR values for females were significantly greater than those for males at most time points (P &amp;lt; 0.05). Conclusion: During prolonged, constant-workload exercise, cardiovascular drift results in a greater increase in %HRR than %VO2R, and this is more pronounced in females than males.

Cardiac output and arteriovenous oxygen difference contribute to lower peak oxygen uptake in patients with fibromyalgia

BackgroundPatients with fibromyalgia (FM) exhibit low peak oxygen uptake (dot{text{V}}O2peak). We aimed to detect the contribution of cardiac output to (dot{text{Q}}) and arteriovenous oxygen difference [text{C}(text{a-v})text{O}_{2}] to dot{text{V}}text{O}_{2} from rest to peak exercise in patients with FM.MethodsThirty-five women with FM, aged 23 to 65 years, and 23 healthy controls performed a step incremental cycle ergometer test until volitional fatigue. Alveolar gas exchange and pulmonary ventilation were measured breath-by-breath and adjusted for fat-free body mass (FFM) where appropriate. dot{text{Q}} (impedance cardiography) was monitored. text{C}(text{a-v})text{O}_{2} was calculated using Fick’s equation. Linear regression slopes for oxygen cost (∆dot{text{V}}O2/∆work rate) and dot{text{Q}} to text{V}O2 (∆dot{text{Q}}/∆dot{text{V}}O2) were calculated. Normally distributed data were reported as mean ± SD and non-normal data as median [interquartile range].Resultsdot{text{V}}O2peak was lower in FM patients than in controls (22.2 ± 5.1 vs. 31.1 ± 7.9 mL∙min−1∙kg−1, P < 0.001; 35.7 ± 7.1 vs. 44.0 ± 8.6 mL∙min−1∙kg FFM−1, P < 0.001). dot{text{Q}} and C(a-v)O2 were similar between groups at submaximal work rates, but peak dot{text{Q}} (14.17 [13.34–16.03] vs. 16.06 [15.24–16.99] L∙min−1, P = 0.005) and C(a-v)O2 (11.6 ± 2.7 vs. 13.3 ± 3.1 mL O2∙100 mL blood−1, P = 0.031) were lower in the FM group. No significant group differences emerged in ∆dot{text{V}}O2/∆work rate (11.1 vs. 10.8 mL∙min−1∙W−1, P = 0.248) or ∆dot{text{Q}}/∆dot{text{V}}O2 (6.58 vs. 5.75, P = 0.122) slopes. ConclusionsBoth dot{text{Q}} and C(a-v)O2 contribute to lower dot{text{V}}O2peak in FM. The exercise responses were normal and not suggestive of a muscle metabolism pathology.Trial registrationClinicalTrials.gov, NCT03300635. Registered 3 October 2017—Retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT03300635.

Peripheral Arterial Stiffness is Associated with Maximal Oxygen Uptake in Athletes.

Increased central arterial stiffness is associated with decreased maximal oxygen uptake (V̇O2max). Endurance exercise training improves arterial function throughout the whole body, but the relationship between central and peripheral arterial stiffness and V̇O2max is unknown. The present study investigated the relationship between central and peripheral arterial stiffness and V̇O2max in endurance-trained athletes. Twenty-one young male endurance-trained athletes and 12 sedentary controls were included in this study. Resting values for carotid-femoral velocity and femoral-ankle pulse wave velocity were obtained to assess central and peripheral arterial stiffness, respectively. V̇O2max was obtained by incremental cycle ergometer testing. Both carotid-femoral pulse wave velocity (P=0.019) and femoral-ankle pulse wave velocity (P=0.028) were lower in athletes than in controls. V̇O2max was significantly higher in athletes compared to controls (P<0.001). Significant correlations were found between carotid-femoral pulse wave velocity and V̇O2max (r=-0.510, P=0.018) and between femoral-ankle pulse wave velocity and V̇O2max (r=-0.472, P=0.031) in athletes. However, no correlations were evident in controls. These results suggest that higher V̇O2max is associated with lower peripheral arterial stiffness in addition to central arterial stiffness among endurance-trained athletes.

Association Between Ferritin Levels and Altitude-Dependent Cardiorespiratory Fitness in Mountain Guides.

Pühringer, Reinhard, Martina Muckenthaler, and Martin Burtscher. Association between ferritin levels and altitude-dependent cardiorespiratory fitness in mountain guides. High Alt Med Biol. 24:139-143, 2023. Background: Higher ferritin levels may be associated with lower cardiorespiratory fitness (CRF; i.e., maximal oxygen uptake, VO2max) and may represent early markers of cardiovascular risk but may also support high-altitude acclimatization. To evaluate these potential associations, data recordings from a large sample of male mountain guides have been analyzed. Methods: A total of 154 data sets (including anthropometric data, VO2max, blood lipids, hemoglobin, ferritin, and transferrin levels) of regularly physically active and well-acclimatized mountain guides were available for analyses. Participants performed equal incremental cycle ergometer tests to exhaustion at low (600 m) and (∼1 week later) at moderate altitude (2,000 m). Results: Ferritin levels were positively correlated with levels of hemoglobin (r = 0.29, p < 0.01), total cholesterol (r = 0.18, p < 0.05), triglycerides (r = 0.23, p < 0.01), and low-density lipoprotein (r = 0.22, p < 0.01), and negatively with high-density lipoprotein levels (r = -0.16, p < 0.05) and also with baseline (taken at low altitude) VO2max values (r = -0.19, p < 0.05). In contrast, higher ferritin levels were associated with less VO2max decline from low-to-moderate altitude (r = 0.26, p < 0.01). Conclusion: Higher ferritin levels in male mountain guides are weakly associated with lower CRF and higher prevalence of cardiovascular risk factors but with slightly less reduction in VO2max when acutely exposed to moderate altitude. The clinical relevance of these observations needs further investigation.

Muscle glycogen unavailability and fat oxidation rate during exercise: Insights from McArdle disease.

Carbohydrate availability affects fat metabolism during exercise; however, the effects of complete muscle glycogen unavailability on maximal fat oxidation (MFO) rate remain unknown. Our purpose was to examine the MFO rate in patients with McArdle disease, comprising an inherited condition caused by complete blockade of muscle glycogen metabolism, compared to healthy controls. Nine patients (three women, aged 36±12 years) and 12healthy controls (four women, aged 40±13 years) were studied. Several molecular markers of lipid transport/metabolism were also determined in skeletal muscle (gastrocnemius) and white adipose tissue of McArdle (Pygm p.50R*/p.50R*) and wild-type male mice. Peak oxygen uptake ( ), MFO rate, the exercise intensity eliciting MFO rate (FATmax) and the MFO rate-associated workload were determined by indirect calorimetry during an incremental cycle-ergometer test. Despite having a much lower (24.7±4 vs. 42.5±11.4mLkg-1 min-1 , respectively; P<0.0001), patients showed considerably higher values for the MFO rate (0.53±0.12 vs. 0.33±0.10 gmin-1 , P=0.001), and for the FATmax (94.4±7.2 vs. 41.3±9.1 % of , P<0.0001) and MFO rate-associated workload (1.33±0.35 vs. 0.81±0.54Wkg-1 , P=0.020) than controls. No between-group differences were found overall in molecular markers of lipid transport/metabolism in mice. In summary, patients with McArdle disease show an exceptionally high MFO rate, which they attained at near-maximal exercise capacity. Pending more mechanistic explanations, these findings support the influence of glycogen availability on MFO rate and suggest that these patients develop a unique fat oxidation capacity, possibly as an adaptation to compensate for the inherited blockade in glycogen metabolism, and point to MFO rate as a potential limiting factor of exercise tolerance in this disease. KEY POINTS: Physically active McArdle patients show an exceptional fat oxidation capacity. Maximal fat oxidation rate occurs near-maximal exercise capacity in these patients. McArdle patients' exercise tolerance might rely on maximal fat oxidation rate capacity. Hyperpnoea might cloud substrate oxidation measurements in some patients. An animal model revealed overall no higher molecular markers of lipid transport/metabolism.

Cardiac stroke volume in females and its correlation to blood volume and cardiac dimensions.

We aimed to continuously determine the stroke volume (SV) and blood volume (BV) during incremental exercise to evaluate the individual SV course and to correlate both variables across different exercise intensities. Twenty-six females with heterogeneous endurance capacities performed an incremental cycle ergometer test to continuously determine the oxygen uptake (V̇O2), cardiac output (Q̇) and changes in BV. Q̇ was determined by impedance cardiography and resting cardiac dimensions by 2D echocardiography. Hemoglobin mass and BV were determined using a carbon monoxide-rebreathing method. V̇O2max ranged from 32 to 62 mL·kg−1·min−1. Q̇max and SVmax ranged from 16.4 to 31.6 L·min−1 and 90–170 mL, respectively. The SV significantly increased from rest to 40% and from 40% to 80% V̇O2max. Changes in SV from rest to 40% V̇O2max were negatively (r = −0.40, p = 0.05), between 40% and 80% positively correlated with BV (r = 0.45, p < 0.05). At each exercise intensity, the SV was significantly correlated with the BV and the cardiac dimensions, i.e., left ventricular muscle mass (LVMM) and end-diastolic diameter (LVEDD). The BV decreased by 280 ± 115 mL (5.7%, p = 0.001) until maximum exercise. We found no correlation between the changes in BV and the changes in SV between each exercise intensity. The hemoglobin concentration [Hb] increased by 0.8 ± 0.3 g·dL−1, the capillary oxygen saturation (ScO2) decreased by 4.0% (p < 0.001). As a result, the calculated arterial oxygen content significantly increased (18.5 ± 1.0 vs. 18.9 ± 1.0 mL·dL−1, p = 0.001). A 1 L higher BV at V̇O2max was associated with a higher SVmax of 16.2 mL (r = 0.63, p < 0.001) and Q̇max of 2.5 L·min−1 (r = 0.56, p < 0.01). In conclusion, the SV strongly correlates with the cardiac dimensions, which might be the result of adaptations to an increased volume load. The positive effect of a high BV on SV is particularly noticeable at high and severe intensity exercise. The theoretically expected reduction in V̇O2max due to lower SV as a consequence of reduced BV is apparently compensated by the increased arterial oxygen content due to a higher [Hb].

The Effect Of Sex And Exercise Intensity On Hunger Ratings In Adults: A Pilot Study

Acute exercise transiently suppresses appetite, oftentimes in an intensity dependent manner. However, the majority of prior work only included young adult males, and did not explore the effects of sex on exercise-induced appetite measures. PURPOSE: To determine the effect of exercise intensity and sex on appetite responses in middle-age adult males and females. METHODS: Untrained males (n = 5; age: 46.8 ± 5.8 y; BMI; 22.5 ± 0.84 kg/m2 VO2peak: 34.7 ± 6.7 mL/kg/min) and females (n = 4; age: 43.8 ± 5.4 y; BMI 22.2 ± 0.94 kg/m2;VO2peak: 28.15 ± 2.3 mL/kg/min) completed 3 conditions in a randomized, crossover design: control (C), moderate intensity exercise (at the lactate threshold (LT); MOD), or high intensity (75% of the difference between LT and VO2 peak; HI) exercise. Exercise intensity was determined from a maximal incremental cycle ergometer test. Venous blood was sampled at the end of each 3-min stage and analyzed for lactate. Visits occurred in the morning after an overnight fast. All exercise sessions were calorically matched within subjects. Subjective appetite parameters were assessed via visual analogue scales (VAS) during each condition at: 0 minutes, 60 minutes, 90 minutes, 120 minutes. Area-under-the curve values were calculated using the trapezoidal method for each VAS component. RESULTS: Preliminary inspection of data suggest perception of hunger (units = mm*120 min-1; males: C: 491.1 ± 291.7 MOD: 355.8 ± 107.8, HI: 351.6 ± 129.2;females: C: 539.6 ± 69.5, MOD: 419.6 ± 106.9, HI: 409.5 ± 67.5) satisfaction (males: C: 420.6 ± 174.9, MOD: 293.7 ± 187.65, HI: 395.3 ± 197.05; females: C: 279.0 ± 239.7 MOD: 342.4 ± 159.6, HI: 382.0 ± 146.4), fullness (males: C: 393.6 ± 154.3, MOD: 266.1 ± 163.8, HI: 398.6 ± 176.5; females: C: 247.5 ± 241.2, MOD: 264.4 ± 215.5, HI: 411.5 ± 159.9), and how much you think you can eat (males: C: 653.7 ± 225.9, M: 573.9 ± 239.2, HI: 460.2 ± 248.9; females: CON: 684.4 ± 192.1, MOD: 545.6 ± 107.4, HIGH: 731.0 ± 150.2), are affected in an intensity dependent manner with differing responses between middle aged males and females. CONCLUSIONS: Both exercise intensity and sex may impact subjective ratings of appetite. Supported by The University of Virginia School of Education and Human Development, and National Institute of Diabetes and Digestive and Kidney Diseases (1R01DK12950-01)

Does Wim Hof Method Improve Breathing Economy during Exercise?

(1) Background: Breathing economy during endurance sports plays a major role in performance. Poor breathing economy is mainly characterized by excessive breathing frequency (BF) and low tidal volume (VT) due to shallow breathing. The purpose of this study was to evaluate whether a 4 week intervention based on the Wim Hof breathing method (WHBM) would improve breathing economy during exercise in adolescent runners. (2) Methods: 19 adolescent (16.6 ± 1.53 years) middle- and long-distance runners (11 boys and 8 girls) participated in the study. Participants were randomly divided into experimental (n = 11) and control groups (n = 8). The study was set in the transition period between competitive race seasons and both groups had a similar training program in terms of running volume and intensity over the course of the study. The experimental group performed breathing exercises every day (~20 min/day) for 4 weeks. The control group did not perform any kind of breathing exercise. The breathing exercises consisted of three sets of controlled hyperventilation and consecutive maximum breath holds. Before and after the intervention, participants performed incremental cycle ergometer testing sessions consisting of two minute stages at 1, 2, 3, and 4 W·kg−1 with breath-by-breath metabolic analysis. During the testing sessions, BF, VT, and minute ventilation (VE) were assessed and compared. (3) Results: There were no statistically significant differences (p > 0.05) in BF, VT, or VE between experimental and control groups before or after the intervention. A nonsignificant small-to-large effect for an increase in VE and BF in both groups following the 4 week intervention period was observed, possibly due to a reduction in training volume and intensity owing to the down period between competitive seasons. (4) Conclusions: The 4 week intervention of WHBM did not appear to alter parameters of breathing economy during a maximal graded exercise test in adolescent runners.

Body and mind? Exploring physiological and psychological factors to explain endurance performance in cycling

ABSTRACT Endurance athletes attribute performance not only to physiological factors, but also refer to psychological factors such as motivation. The goal of this study was to quantify the proportion of the variance in endurance performance that is explained by psychological factors in addition to the physiological factor VO2max. Twenty-five athletes of the U17 Swiss Cycling national team (7f, 18 m, 15.3 ± 0.5 years) were examined in a cross-sectional study with psychological factors and VO2max as independent variables and endurance performance in road cycling as dependent variable. Questionnaires were used to assess psychological factors (i.e. use of mental techniques, self-compassion, mental toughness, achievement motivation, and action vs. state orientation). VO2max was measured by a step incremental cycle ergometer test of exhaustion. Endurance performance was measured in a cycling mountain time trial (1,320 m long, incline of 546 meters). A multiple regression model was created by using forward selection of regression model predictors. Results showed that higher VO2max values (β = .48), being male (β = .26), and higher achievement motivation (i.e. perseverance, β = .11) were associated with a better endurance performance. A more frequent use of one particular mental technique (i.e. relaxation techniques, β = .03) was associated with a worse endurance performance. Our study shows that a physiological factor like VO2max explains endurance performance to a large extent but psychological factors account for additional variance. In particular, one aspect of achievement motivation, namely perseverance, was associated with a better endurance performance. HIGHLIGHTS Endurance performance is explained by physiological (e.g. VO2max) and psychological (e.g. perseverance) factors VO2max explains young cyclists’ endurance performance to a large extent Perseverance explained performance beyond the influence of VO2max

Is BMI Associated with Cardiorespiratory Fitness? A Cross-Sectional Analysis Among 8470 Apparently Healthy Subjects Aged 18–94 Years from the Low-Lands Fitness Registry

ObjectiveThe purpose of the present study was to investigate the association between cardiorespiratory fitness (CRF) measured as peak oxygen uptake (VO2peak, expressed in mL/min) and body mass index (BMI) in a large cohort of apparently healthy subjects.MethodsBMI and VO2peak were measured in a cross-sectional study of 8470 apparently healthy adults. VO2peak (mL/min) was determined by an incremental cycle ergometer test to exhaustion. Linear regression analyses were performed to identify predictors of CRF.ResultsThere was no difference in CRF between adults with a normal weight (BMI between 18.5–24.9 kg/m2) and those who were overweight (BMI 25.0–29.9 kg/m2). Subjects who were underweight (BMI < 18.5 kg/m2) as well as females who were obese (BMI ≥ 30.0 kg/m2) showed a reduced CRF compared to the normal and overweight groups. Age, height, and gender were significant predictors of CRF (R2 = 0.467, P < 0.0001); BMI did not add significantly to this relationship.ConclusionOur findings indicate that BMI was not associated with CRF in addition to age, height, and gender. In subjects with a BMI < 18.5 kg/m2, CRF was lower compared to subjects with a BMI between 18.5 and 29.9 kg/m2. In obese subjects, CRF was only lower in females compared to females with a BMI between 18.5 and 29.9 kg/m2. Correcting CRF for BMI may be beneficial for subjects with a low BMI, and females with a BMI ≥ 30.0 kg/m2. The outcome of this study might help to improve the interpretation of exercise testing results in individuals with a low or high BMI.

Comparison of Predicted Exercise Capacity Equations in Adult Korean Subjects.

BackgroundMaximal oxygen uptake (VO2 max) is a useful index to assess exercise capacity. However, there is no reference value for Koreans. This study aimed to compare actual VO2 max and predicted VO2 max using exercise capacity equations in Korean subjects.MethodsThis retrospective study enrolled 383 patients who underwent cardiopulmonary exercise test (CPET) with incremental maximal cycle ergometer test at Asan Medical Center from January 2020 to May 2021. Stage 1 and 2 lung cancer patients with normal lung function and healthy persons of 50 subjects who had maximal CPET were analyzed.ResultsThe subjects were aged 65 ± 13 years and predominantly male (74%). CPET results were as follows: absolute VO2 max, 1.2 ± 0.3 L/min; body weight referenced VO2 max, 20 ± 3.9 mL/kg/min; peak work rate, 94 ± 24 watts; peak heart rate, 142 ± 21 bpm; peak O2 pulse, 10 ± 3 mL/beat; minute ventilation, 59 ± 14 L/min; peak respiratory rate, 34 ± 6 breaths per minute; and peak breathing reserve, 41 ± 18%. There was significant discordance between the measured and predicted absolute VO2 max using the Jones, Hansen, and Wasserman prediction equations developed for Caucasian population (P < 0.001). Agreement using Bland-Altman test between true and predicted absolute VO2 max was the best in Chinese equation (−0.03, 2SD = 0.55) compared to Jones (0.42, 2SD = 1.07), Hansen (0.44, 2SD = 0.86), and Wasserman (0.42, 2SD = 0.86) equations.ConclusionThe reference value and prediction equation from studies including primarily Caucasians may not be appropriate for Koreans. Since the mean difference is the lowest in Chinese equation, the Chinese equation might be used for the Korean adult population.

Age and Training-Related Changes on Body Composition and Fitness in Male Amateur Cyclists.

Master athletes are considered as a model of healthy aging because they can limit the age-related decline of physiological abilities compared to sedentary individuals. The main objective of this study is to analyze age-related changes and annual training on body composition (BC) and cardiorespiratory fitness (CRF) parameters. The participants in this retrospective cross-sectional study were 176 male cyclists, aged 40–60 years. BC was evaluated through anthropometric measurements and CRF was determined by an incremental cycle ergometer test to exhaustion. A comparative study between age groups was carried out through a one-way ANOVA test and the associations between the variables were assessed by Spearman’s correlation coefficients and multiple regression analysis to estimate the performance. Training was generally associated with a decrease in both body weight and body fat (p < 0.05). A decrease in resting heart rate was observed as a vagal effect of kilometers cycled per year (p < 0.05). Kilometers cycled per year were associated with an increase in peak power output, which was larger in the master 40 group (p < 0.05) with a non-significant upward in VO2max (p > 0.05). In the performance prediction model, the included variables explained 52% of the variance. In summary, the changes induced by age were minimal in BC and negligible in CRF, whereas HR decreased with age. Training load was generally associated with a decrease in body weight, BMI and body fat percentage that was particularly notable in the abdominal skin folds. A decrease in HRrest was observed as a vagal effect due to kilometers cycled per year, and age did not seem to have a significant effect. The annual cycling kilometers were associated with to high PPO that is greater in the M40 group and a non-significant upward trend in VO2max.

Does Moderate Altitude Affect VO2max in Acclimatized Mountain Guides?

Pühringer, Reinhard, Hannes Gatterer, Martin Berger, Michael Said, Martin Faulhaber, and Martin Burtscher. Does moderate altitude affect VO2max in acclimatized mountain guides? High Alt Med Biol. 23:37-42, 2022. Background: Altitude exposure reduces maximal oxygen uptake (VO2max). Usually, the reduction is not restored with acclimatization (at least at altitudes above 2,500 m) and is more pronounced in highly trained athletes compared to nonathletes. It still remains to be elucidated whether these also apply for well-acclimatized individuals (i.e., mountain guides) acutely exposed to moderate altitude (i.e., 2,000 m). Methods: A total of 128 acclimatized male mountain guides of the Austrian armed forces (42.2 ± 7.0 years, 177.8 ± 5.6 cm, 77.2 ± 7.0 kg) of different fitness levels performed 2 incremental cycle ergometer tests 1 week apart, one at low (600 m) and one at moderate altitude (2,000 m). Oxygen uptake, heart rate (HR), and lactate concentration were measured during the tests. Results: In acclimatized mountain guides, lower baseline VO2max levels were associated with better preservation of VO2max at moderate altitude compared to higher levels. At moderate altitude, physiological responses (HR and blood lactate at 100 W) at a submaximal exercise intensity of 100 W remained unchanged or were even slightly reduced in both groups. Conclusions: Long-term acclimatization to moderate altitude may prevent the VO2max decline at a moderate altitude of 2,000 m particularly in subjects with lower VO2max levels, that is, below the 80th percentile (for age and sex). In people with higher fitness levels, VO2max may still be negatively affected. These results are of practical relevance, for example, for workers, athletes, ski and mountain guides, military staff, or rescue staff who regularly or continuously have to perform at moderate altitude.

Energy metabolism during exercise in patients with β-enolase deficiency (GSDXIII).

AimTo investigate the in vivo skeletal muscle metabolism in patients with β‐enolase deficiency (GSDXIII) during exercise, and the effect of glucose infusion.MethodsThree patients with GSDXIII and 10 healthy controls performed a nonischemic handgrip test as well as an incremental cycle ergometer test measuring maximal oxidative consumption (VO2max) and a 1‐hour submaximal cycle test at an intensity of 65% to 75% of VO2max. The patients repeated the submaximal exercise after 2 days, where they received a 10% iv‐glucose supplementation.ResultsPatients had lower VO2max than healthy controls, and two of three patients had to stop prematurely during the intended 1‐hour submaximal exercise test. During nonischemic forearm test, all patients were able to produce lactate in normal amounts. Glucose infusion had no effect on patients' exercise capacity.ConclusionsPatients with GSDXIII experience exercise intolerance and episodes of myoglobinuria, even to the point of needing renal dialysis, but still retain an almost normal anaerobic metabolic response to submaximal intensity exercise. In accordance with this, glucose supplementation did not improve exercise capacity. The findings show that GSDXIII, although causing episodic rhabdomyolysis, is one of the mildest metabolic myopathies affecting glycolysis.

Power Output and Efficiency During Supine, Recumbent, and Upright Cycle Ergometry.

Recumbent and supine cycling are common exercise modes in rehabilitation and clinical settings but the influence of postures on work efficiency is unclear. Therefore, the aim of this study was to compare metabolic and ventilatory efficiency during upright, recumbent, and supine postures. Potential differences should be assessed for suitable diagnostics and for prescriptions of training that probably is performed in alternative postures. Eighteen healthy subjects (age: 47.2 ± 18.4 years; 10 female, 8 male) participated in the study and each completed three incremental cycle ergometer tests until exhaustion in upright, recumbent (40°), and supine positions. Gas exchange, heart rate (HR), and lactate concentrations were analyzed and efficiency was calculated subsequently. Testing sessions were performed in random order within a 2-week period. Upright cycling resulted in significantly higher peak values [power output, oxygen uptake (Vo2), HR] as well as performance at lactate and ventilatory thresholds in comparison to recumbent or supine positions. Vco2/Vo2 slope and ventilatory efficiency (VE/Vco2 slope) were not affected by posture. Aerobic work efficiency (Vo2/P slope) and gross efficiency (GE) differed significantly between postures. Hereby, GE was lowest in supine cycling, particularly obvious in a mainly aerobic condition at 70 Watt [Median 11.6 (IQR 10.9–13.3) vs. recumbent: 15.9 (IQR 15.6–18.3) and upright: 17.4 (IQR 15.1–18.3)]. Peak power as well as GE and work efficiency values are influenced by cycling position, reinforcing the importance of adjusting test results for training prescriptions. Surprisingly, ventilatory efficiency was not affected in this study and therefore does not seem to falsify test results for pulmonary diagnostics.

Effect of Exercise-Induced Reductions in Blood Volume on Cardiac Output and Oxygen Transport Capacity.

We wanted to demonstrate the relationship between blood volume, cardiac size, cardiac output and maximum oxygen uptake (O2max) and to quantify blood volume shifts during exercise and their impact on oxygen transport. Twenty-four healthy, non-smoking, heterogeneously trained male participants (27 ± 4.6 years) performed incremental cycle ergometer tests to determine O2max and changes in blood volume and cardiac output. Cardiac output was determined by an inert gas rebreathing procedure. Heart dimensions were determined by 3D echocardiography. Blood volume and hemoglobin mass were determined by using the optimized CO-rebreathing method. The O2max ranged between 47.5 and 74.1 mL⋅kg–1⋅min–1. Heart volume ranged between 7.7 and 17.9 mL⋅kg–1 and maximum cardiac output ranged between 252 and 434 mL⋅kg–1⋅min–1. The mean blood volume decreased by 8% (567 ± 187 mL, p = 0.001) until maximum exercise, leading to an increase in [Hb] by 1.3 ± 0.4 g⋅dL–1 while peripheral oxygen saturation decreased by 6.1 ± 2.4%. There were close correlations between resting blood volume and heart volume (r = 0.73, p = 0.002), maximum blood volume and maximum cardiac output (r = 0.68, p = 0.001), and maximum cardiac output and O2max (r = 0.76, p < 0.001). An increase in maximum blood volume by 1,000 mL was associated with an increase in maximum stroke volume by 25 mL and in maximum cardiac output by 3.5 L⋅min–1. In conclusion, blood volume markedly decreased until maximal exhaustion, potentially affecting the stroke volume response during exercise. Simultaneously, hemoconcentrations maintained the arterial oxygen content and compensated for the potential loss in maximum cardiac output. Therefore, a large blood volume at rest is an important factor for achieving a high cardiac output during exercise and blood volume shifts compensate for the decrease in peripheral oxygen saturation, thereby maintaining a high arteriovenous oxygen difference.

Validity and reproducibility of VO2 max testing in a respiration chamber.

The aim of this study was to investigate whether VO2max can be accurately measured in a respiration chamber. Thirty participants aged 23.4 ± 3.9 years with a wide range in VO2max were included. Participants performed four incremental cycle ergometer tests (VO2max) with a minimum of 5 days between tests. These tests consisted of one familiarization test with face mask, followed by two VO2max tests in the respiration chamber and one test with face mask in randomized order. Oxygen consumption and CO2 production were measured continuously using Omnical (Maastricht University, the Netherlands) gas analysis system. The mean VO2max was 3634 ± 766 ml, which resulted in mean VO2max per lean body mass of 60.8 ± 8.0 ml/kg. Repeated respiration chamber tests showed a high concordance, and no significant differences were detected between tests (Lin's concordance correlation coefficient (Rc) = 0.99; ∆70 ± 302 ml/min; p = .38). There was high concordance between the mean VO2max from both respiration chamber tests and the mean face mask tests, and no significant difference (Rc = 0.99; ∆41 ± 173 ml/min; p = .22) was observed. The Bland‐Altman plots showed no proportional bias between different tests. In conclusion, the respiration chamber has been found to be a valid and reproducible method for measuring VO2max. New research opportunities are possible in the respiration chamber, such as maximal exercise testing during 24‐hour measurements.