High-Intensity Interval vs. Moderate-Intensity Continuous Training in Parkinson's Disease: A Randomized Trial.

Exercise training is recommended to improve quality of life in those living with Parkinson's Disease (PD); however, the optimal prescription to improve cardiorespiratory fitness and disease-related motor symptoms remains unknown. Twenty-nine participants with PD were randomly allocated to either 10-weeks of high-intensity interval training (HIIT) (n=15; 6 female) or moderate-intensity continuous training (MICT) (n=14; 5 female). The primary outcome was the change in maximal oxygen consumption (VO2peak). Secondary outcomes included changes in the Unified Parkinson's Disease Rating Scale (UPDRS) Part III motor score, Parkinson's Disease Fatigue Scale (PFS-16), resting and exercise cardiovascular measures, gait, balance, and knee extensor strength and fatigability. Exercise training increased VO2peak (main effect of time, P<0.01), with a clinically-meaningful difference in the change following HIIT vs. MICT (∆3.7±3.7 vs. 1.7±3.2 ml∙kg-1∙min-1, P=0.099). The UPDRS motor score improved over time (P<0.001) but without any differences between HIIT vs. MICT (∆-9.7±1.3 vs. -8.4±1.4, P=0.51). Self-reported subjective fatigue (PFS-16) decreased over time (P<0.01) but was similar between HIIT and MICT groups (P=0.6). Gait, balance, blood pressure, and heart rate were unchanged with training (all P>0.09). Knee extensor strength increased over time (P=0.03) but did not differ between HIIT vs. MICT (∆8.2±5.9 vs. 11.7±6.2 Nm, P=0.69). HIIT alone increased muscular endurance of the knee extensors during an isotonic task to failure (P=0.04). In participants with PD, HIIT and MICT both increased VO2peak and led to improvements in motor symptoms and perceived fatigue; HIIT may offer the potential for larger changes in VO2peak and reduced knee extensor fatigability.

Test-Retest Reliability of Running Economy and Metabolic and Cardiorespiratory Parameters During a Multistage Incremental Treadmill Test in Male Middle- and Long-Distance Runners.

This study investigated the test-retest reliability of running economy (RE) and metabolic and cardiorespiratory parameters related to endurance running performance using a multistage incremental treadmill test. On two occasions separated by 21-28 days, 12 male middle- and long-distance runners ran at 10, 11, 12, 13, and 14 km/hr for 8 min each stage, immediately followed by a ramp test to volitional exhaustion. Carbohydrate (10% maltodextrin solution) was consumed before and during the test to provide ∼1 g/min of exercise. RE, minute ventilation (V˙E), oxygen consumption (V˙O2), carbon dioxide production (V˙CO2), respiratory exchange ratio (RER), heart rate (HR), ratings of perceived exertion (RPE), and blood glucose and lactate concentrations were recorded for each stage and at volitional exhaustion. Time-to-exhaustion (TTE) and peak oxygen consumption (V˙O2peak) during the ramp test were also recorded. Absolute reliability, calculated as the coefficient of variation (CV) between repeated measures, ranged from 2.3% to 3.1% for RE, whereas relative reliability, calculated as the intraclass correlation coefficient (ICC), ranged from .42 to .79. V˙E, V˙O2, V˙O2peak, V˙CO2, RER, and HR had a CV of 1.1%-4.3% across all stages. TTE and RPE had a CV of 7.2% and 2.3%-10.8%, respectively, while glucose and lactate had a CV of 4.0%-17.8%. All other parameters, except for blood glucose, were demonstrated to have good-to-excellent relative reliability assessed by ICC. Measures of RE, V˙O2peak, and TTE were reliable during this two-phase multistage incremental treadmill test in a cohort of trained and highly trained male middle- and long-distance runners.

Impaired Cardiorespiratory Fitness of Elite Athletes after Asymptomatic or Mild SARS-CoV-2 Infection.

Background and Objectives: The aim of the study was to evaluate the health status of professional athletes after recovering from COVID-19 and the impact that SARS-CoV-2 had on their overall cardiorespiratory fitness, which was done by conducting cardiopulmonary exercise testing (CPET). Materials and Methods: A total of twenty-seven professional basketball players (Euroleague Basketball and the ABA League) participated in the study. CPET was performed before (as part of their regular preparticipation exam, during the pre-season period), as well as after SARS-CoV-2 infection (after two weeks of home isolation, during the competitive part of the season). CPET was performed on a treadmill, while cardiovascular, respiratory, and metabolic functions were evaluated by using a breath-by-breath analysis technique (Quark CPET system manufactured by Cosmed, Rome, Italy). Results: Maximal oxygen consumption and aerobic efficiency were significantly reduced after SARS-CoV-2 infection (p = 0.000). An obvious decrease in oxygen pulse was observed during CPET after recovering from COVID-19 (p = 0.001), as was deterioration of ventilatory efficiency. Internal respiration was the most negatively affected. An early transition from aerobic to anaerobic mechanisms of creating energy for work and intensive metabolic fatigue were obvious after SARS-CoV-2 infection. Conclusions: Although it was believed that SARS-CoV-2 only affects the cardiopulmonary status of the elderly population and people with associated comorbidities, it is clear from this research that professional athletes can also be at certain risk. Even though no pathological cardiovascular and respiratory changes were found in athletes after COVID-19, results showed significantly decreased cardiorespiratory fitness, with an emphasis on internal respiration.

Seasonal Variation and the Effect of the Transition Period on Physical Fitness Parameters in Youth Female Soccer Players.

This study examined seasonal variation and the effect of the transition period on physical fitness parameters in female youth soccer players. Twenty-four players (13-17 years old) were assessed through field and laboratory testing. They completed laboratory testing three times: (1) at the beginning of the season (post-preseason), (2) at the end of the regular season (postseason), and (3) following the transition period (preseason). Field testing was conducted post-preseason and postseason. Results indicated that weight and body fat significantly increased from post-preseason to postseason and following the transition period. A paired samples T-test revealed that the players performed significantly better in the vertical jump and 30 m sprint test (all p < 0.01) postseason compared to post-preseason. Also, it was indicated that torque production for the right quadriceps, left quadriceps, and right hamstring (all p < 0.01) was significantly reduced after the transition period by 10%, 11.8%, and 10.5%, respectively. Cardiorespiratory measurements demonstrated that performance on an incremental cardiopulmonary treadmill test, maximal oxygen consumption, velocity at the first ventilatory threshold, velocity at the second ventilatory threshold, and velocity at maximal oxygen consumption (all p < 0.01) were significantly reduced postseason and following the transition period. Based on the results, coaches and trainers should primarily focus on maintaining the aerobic capacity of the players during the season, as it has been indicated to be reduced from the beginning to the end of the competitive period (VO2max reduced by 3.3%). In addition, they should focus on maintaining lower body strength and aerobic capacity during the transition period.

A revision of maximal oxygen consumption and exercise capacity at altitude 70 years after the first climb of Mount Everest.

On the 70th anniversary of the first climb of Mount Everest by Edmund Hillary and Tensing Norgay, we discuss the physiological bases of climbing Everest with or without supplementary oxygen. After summarizing the data of the 1953 expedition and the effects of oxygen administration, we analyse the reasons why Reinhold Messner and Peter Habeler succeeded without supplementary oxygen in 1978. The consequences of this climb for physiology are briefly discussed. An overall analysis of maximal oxygen consumption ( V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ ) at altitude follows. In this section, we discuss the reasons for the non-linear fall of V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ at altitude, we support the statement that it is a mirror image of the oxygen equilibrium curve, and we propose an analogue of Hill's model of the oxygen equilibrium curve to analyse the V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ fall. In the following section, we discuss the role of the ventilatory and pulmonary resistances to oxygen flow in limiting V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ , which becomes progressively greater while moving toward higher altitudes. On top of Everest, these resistances provide most of the V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ limitation, and the oxygen equilibrium curve and the respiratory system provide linear responses. This phenomenon is more accentuated in athletes with elevated V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ , due to exercise-induced arterial hypoxaemia. The large differences in V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ that we observe at sea level disappear at altitude. There is no need for a very high V ̇ O 2 max ${\dot V_{{{\mathrm{O}}_{\mathrm{2}}}{\mathrm{max}}}}$ at sea level to climb the highest peaks on Earth.

Glucose volume of distribution affects insulin sensitivity measured by intravenous glucose tolerance test.

AIM: To determine whether glucose volume of distribution (VdGLUCOSE ) affects the diagnosis of impaired insulin sensitivity (IS) when using an intravenous glucose tolerance test (IVGTT). METHODS: Individuals with distinct levels of IS underwent IVGTT after an overnight fast. The prediabetic group (Prediab; n = 33) differed from the healthy group (Healthy; n = 14) in their larger glycosylated hemoglobin (HbA1c of 5.9 ± 0.3 vs. 5.4 ± 0.1%; 41 ± 4 vs. 36 ± 1 mmol/mol; p < 0.001), percent body fat (37 ± 6 vs. 24 ± 3%; p < 0.001) and cardiovascular fitness level (VO2MAX 22 ± 5 vs. 44 ± 5 mL of O2 ·kg-1 ·min-1 ; p < 0.001). Ten minutes after intravenous infusion of the glucose bolus (i.e., 35 g in a 30% solution), VdGLUCOSE was assessed from the increases in plasma glucose concentration. IS was calculated during the next 50 min using the slope of glucose disappearance and the insulin time-response curve. RESULTS: VdGLUCOSE was higher in Healthy than in Prediab (230 ± 49 vs. 185 ± 21 mL·kg-1 ; p < 0.001). VdGLUCOSE was a strong predictor of IS (ß standardized coefficient 0.362; p = 0.004). VO2MAX was associated with VdGLUCOSE and IS (Pearson r = 0.582 and 0.704, respectively; p < 0.001). However, body fat was inversely associated with VdGLUCOSE and IS (r = -0.548 and -0.555, respectively; p < 0.001). CONCLUSIONS: Since fat mass is inversely related to VdGLUCOSE and in turn, VdGLUCOSE affects the calculations of IS, the IV glucose bolus dose should be calculated based on fat-free mass rather than body weight for a more accurate diagnosis of impaired IS.

NIRS-Derived Muscle-Deoxygenation and Microvascular Reactivity During Occlusion-Reperfusion at Rest Are Associated With Whole-Body Aerobic Fitness.

Purpose: Near-infrared spectroscopy (NIRS) indices during arterial occlusion-reperfusion maneuver have been used to examine the muscle's oxidative metabolism and microvascular function-important determinants of whole-body aerobic-fitness. The association of NIRS-derived parameters with whole-body VO2max was previously examined using a method requiring exercise (or electrical stimulation) followed by multiple arterial occlusions. We examined whether NIRS-derived indices of muscle deoxygenation and microvascular reactivity assessed during a single occlusion-reperfusion at rest are (a) associated with maximal/submaximal indices of whole-body aerobic-fitness and (b) could discriminate individuals with different VO2max. We, also, investigated which NIRS-parameter during occlusion-reperfusion correlates best with whole-body aerobic-fitness. Methods: Twenty-five young individuals performed an arterial occlusion-reperfusion at rest. Changes in oxygenated- and deoxygenated-hemoglobin (O2Hb and HHb, respectively) in vastus-lateralis were monitored; adipose tissue thickness (ATT) at NIRS-application was assessed. Participants also underwent a maximal incremental exercise test for VO2max, maximal aerobic velocity (MAV), and ventilatory-thresholds (VTs) assessments. Results: The HHbslope and HHbmagnitude of increase (occlusion-phase) and O2Hbmagnitude of increase (reperfusion-phase) were strongly correlated with VO2max (r = .695-.763, p < .001) and moderately with MAV (r = .468-.530; p < .05). O2Hbmagnitude was moderately correlated with VTs (r = .399-.414; p < .05). After controlling for ATT, the correlations remained significant for VO2max (r = .672-.704; p < .001) and MAV (r = .407; p < .05). Individuals in the high percentiles after median and tritile splits for HHbslope and O2Hbmagnitude had significantly greater VO2max vs. those in low percentiles (p < .01-.05). The HHbslope during occlusion was the best predictor of VO2max. Conclusion: NIRS-derived muscle deoxygenation/reoxygenation indices during a single arterial occlusion-reperfusion maneuver are strongly associated with whole-body maximal indices of aerobic-fitness (VO2max, MAV) and may discriminate individuals with different VO2max.

Validation of the maximal cardiopulmonary exercise test in adolescents with major depressive disorder and comparison of cardiorespiratory fitness with sex- and age-related control values.

Endurance training has been shown to be effective in treating adolescents with major depressive disorder (MDD). To integrate endurance training into the therapeutic setting and the adolescents' daily lives, the current performance status of the adolescents should be accurately assessed. This study aims to examine adolescents with MDD concerning exhaustion criteria during a cardiopulmonary exercise test (CPET), as well as to compare the values obtained thereon with sex- and age-related control values. The study included a retrospective examination of exhaustion criteria ((i) oxygen consumption (V̇O2) plateau, (ii) peak respiratory exchange ratio (RERpeak) > 1.0, (iii) peak heart rate (HRpeak) ≥ 95% of the age-predicted maximal HR, and (iv) peak blood lactate concentration (BLCpeak) > 8.0 mmol⋅L-1) during a graded CPET on a cycle ergometer in adolescents with MDD (n = 57). Subsequently, maximal V̇O2, peak minute ventilation, V̇O2 at the first ventilatory threshold, and peak work rate of participants who met at least two of four criteria were compared with published control values using an independent-sample t-test. Thirty-three percent of the total population achieved a V̇O2 plateau and 75% a RERpeak > 1.0. The HR and BLC criteria were met by 19% and 22%, respectively. T-test results revealed significant differences between adolescents with MDD and control values for all outcomes. Adolescents with MDD achieved between 56% and 83% of control values.   Conclusions: The study shows that compared with control values, fewer adolescents with MDD achieve the exhaustion criteria on a CPET and adolescents with MDD have significantly lower cardiorespiratory fitness.   Clinical trial registration: No. U1111-1145-1854. What is Known: • It is already known that endurance training has a positive effect on depressive symptoms. What is New: • A relevant proportion of adolescents with major depressive disorder do not achieve their V̇O2max during a graded cardiopulmonary exercise test. • Adolescents with major depressive disorder have significantly lower cardiorespiratory fitness compared to sex- and age-related control values.

Evolución de las ecuaciones del Shuttle Run Test 20m para la obtención del VO2máx: Revisión documental / Evolution of the equations of the Shuttle Run Test 20m to obtain VO2max: Documentary review

Para la evaluación del fitness cardiorrespiratorio existen pruebas directas en laboratorio que proporcionan información objetiva respecto a esta cualidad. No obstante, cuando no se cuenta con los recursos se recurre al uso de pruebas de campo como el Shuttle Run Test 20 metros (SRT-20m), el cual busca establecer el VO2max para cada sujeto, relacionando los valores obtenidos con aspectos como la composición corporal, edad y contexto poblacional, siendo una de las pruebas más confiables y con concordancia clínica existente. El propósito fue reconocer los cambios o variaciones presentes en los modelos matemáticos o lineales empleados en esta prueba con diferentes grupos poblacionales. Se realizó una revisión de la literatura bajo el marco básico para revisiones integradoras con algunas precisiones dadas por la guía PRISMA, identificando en su mayoría estudios de corte transversal los cuales evidencian los cambios realizados al planteamiento de la fórmula matemática donde las variables que inciden en el valor resultante para la resistencia aeróbica son: velocidad final, etapa de la prueba, edad y aspectos antropométricos del sujeto. Por lo anterior, se concluye que, para efectos prácticos, la estimación del VO2máx debe considerar factores intrínsecos del sujeto y aquellos relacionados con la ejecución de la prueba (AU)

For the evaluation of cardiorespiratory fitness, there are direct laboratory tests that provide objective information regarding this quality. However, when the resources are not available, the use of field tests such as the Shuttle Run Test 20 meters (SRT-20m) is used, which seeks to establish the VO2max for each subject, relating the values obtained with aspects such as body composition, age, and population context, being one of the most reliable tests with existing clinical agreement. The purpose was to recognize the changes or variations present in the mathematical or linear models used in this test with different population groups. A review of the literature was carried out under the basic framework for integrative reviews with some clarifications given by the PRISMA guide, identifying mostly cross-sectional studies which show the changes made to the approach of the mathematical formula where the variables that affect the resulting value for aerobic endurance are final speed, stage of the test, age, and anthropometric aspects of the subject. Therefore, it is concluded that, for practical purposes, the estimation of VO2max should consider intrinsic factors of the subject and those related to the execution of the test (AU)

Adaptations to Optimized Interval Training in Soccer Players: A Comparative Analysis of Standardized Methods for Individualizing Interval Interventions.

Accurately prescribing supramaximal interval training facilitates targeting desired physiological adaptations. This study compared the homogeneity of adaptations in cardiorespiratory parameters to supramaximal [i.e., intensities beyond maximal aerobic speed (MAS)] interval interventions prescribed using anaerobic speed reserve (ASR), the speed attained at the end of 30-15 Intermittent Fitness Test (VIFT), and MAS. Using repeated-measures factorial design, and during the off-season phase of the athletes' yearly training cycle, thirty national-level soccer players (age = 19 ± 1.6 years; body mass = 78.9 ± 1.6 kg; height = 179 ± 4.7 cm; Body fat = 11 ± 0.9%) were randomized to interventions consisting of 2 sets of 6, 7, 8, 7, 8, and 9-min intervals (from 1st to 6th week), including 15 s running at Δ%20ASR (MAS + 0.2 × ASR), 120%MAS, or 95%VIFT followed by 15 s passive recovery. All ASR, VIFT, and MAS programs sufficiently stimulated adaptive mechanisms, improving relative maximal oxygen uptake [V̇O2max (p < 0.05; ES = 1.6, 1.2, and 1.1, respectively)], absolute V̇O2max (p < 0.05; ES = 1.5, 1.1, and 0.7), ventilation [V̇E (p < 0.05; ES = 1.6, 1.1, and 1.1)], O2 pulse [V̇O2/HR (p < 0.05; ES = 1.4, 1.1, and 0.6)], first and second ventilatory threshold [VT1 (p < 0.05; ES = 0.7, 0.8, and 0.7) and VT2 (p < 0.05; ES = 1.1, 1.1, and 0.8)], cardiac output [Q̇max (p = 1.5, 1.0, and 0.7)], and stroke volume [SVmax (p < 0.05; ES = 0.9, 0.7, and 0.5)]. Although there was no between-group difference for the change in the abovementioned variables over time, supramaximal interval training prescribed using ASR and VIFT resulted in a lower coefficient of variation [CV (inter-individual variability)] in physiological adaptations compared to exercise intensity determined as a proportion of MAS. Expressing the intensity of supramaximal interval programs according to the athlete's ASR and VIFT would assist in accurately prescribing interventions and facilitate imposing mechanical and related physiological stimulus according to the athletes' physiological ceiling. Such an approach leads to identical stimulation across athletes with differing profiles and potentially facilitates more homogenized adaptations.

Development of Machine Learning Model for VO2max Estimation Using a Patch-Type Single-Lead ECG Monitoring Device in Lung Resection Candidates.

A cardiopulmonary exercise test (CPET) is essential for lung resection. However, performing a CPET can be challenging. This study aimed to develop a machine learning model to estimate maximal oxygen consumption (VO2max) using data collected through a patch-type single-lead electrocardiogram (ECG) monitoring device in candidates for lung resection. This prospective, single-center study included 42 patients who underwent a CPET at a tertiary teaching hospital from October 2021 to July 2022. During the CPET, a single-lead ECG monitoring device was applied to all patients, and the results obtained from the machine-learning algorithm using the information extracted from the ECG patch were compared with the CPET results. According to the Bland-Altman plot of measured and estimated VO2max, the VO2max values obtained from the machine learning model and the FRIEND equation showed lower differences from the reference value (bias: -0.33 mL·kg-1·min-1, bias: 0.30 mL·kg-1·min-1, respectively). In subgroup analysis, the developed model demonstrated greater consistency when applied to different maximal stage levels and sexes. In conclusion, our model provides a closer estimation of VO2max values measured using a CPET than existing equations. This model may be a promising tool for estimating VO2max and assessing cardiopulmonary reserve in lung resection candidates when a CPET is not feasible.

The "Aging Effect" of BMI on Cardiorespiratory Fitness: A New Insight on Functional Evaluation in Obesity.

Cardiorespiratory fitness (CRF) is a strong predictor of morbidity and mortality in patients with obesity. This study investigates the CRF range and its clinical determinants in patients with obesity. Moreover, a practical proposal for CRF interpretation is provided. In this study, 542 patients (69% females) with BMI ≥ 30 kg/m2 performed an incremental cardiopulmonary exercise test (CPET). Patients had a median (IQR) age of 47.0 (6.2) years with a mean BMI of 41.7 ± 6.7 kg/m2. Normal values curves of VO2peak/kg showed a median (IQR) of 20.3 (37.6) mL/min/kg. The lower-quartile threshold of VO2peak/kg was at 17.9 mL/min/kg. Analysis of covariance revealed that VO2peak/kg inversely correlates with age and BMI with a significant age × BMI interaction effect (all p < 0.0001); as BMI class increases, CRF decreases, but a smaller age-related decline in VO2peak/kg is observed. A multivariate logistic regression demonstrated that belonging to the lower quartile of VO2peak/kg was independently determined by age (OR 2.549, 95% CI 1.205-5.392, p < 0.0001) and BMI (OR 5.864, 95% CI 2.920-11.778, p < 0.0001) but not by comorbidities. At very high BMI, the effect of age on functional capacity is lower, suggesting that BMI acts as an "aging factor" on CRF. Age and BMI, but not comorbidities, are independent determinants of low VO2peak/kg.

The effects of high-intensity interval training at the anaerobic and psychomotor fatigue thresholds on physiological parameters in young soccer players: a prospective study.

This study aimed to investigate the effects of a 4-week specific high-intensity interval training (HIIT) program performed between the anaerobic threshold (ANT) and the psychomotor fatigue threshold (PFT) on physiological parameters in 14 professional soccer players at the under-17 level. The first and second stages of the research protocol included a treadmill running exercise with increasing load and six 3-min four-versus-four games of soccer with a 3-min break between games. Players then participated in a training microcycle involving three specific HIIT exercises twice per week for 4 weeks, after which they repeated stages one and two, followed by an assessment of changes. The measurement of lactate (LA) determined ANT, whereas the choice reaction time (CRT) indicated PFT among other selected physiological parameters. The repeated-measure analysis of variance (ANOVA) compared mean values for the examined variables using Bonferroni post hoc test. It demonstrated significantly increased maximal oxygen consumption (VO2 max) from 45.9 ± 3.0 to 48.7 ± 2.6 at the ANT and from 49.1 ± 3.4 to 52.0 ± 3.6 on the PFT after 4 weeks of training. A significant increase in the running speed (RS) at both thresholds and heart rate (HR) at the ANT (p ≤ 0.05) was also recorded. Moreover, the players exceeded their intensity of effort during ANT while playing four-versus-four soccer matches, but they did not reach intensity during PFT. In conclusion, the findings of the study demonstrated that both thresholds shifted toward higher loads and the proposed specific HIIT effectively increased the exercise capacity of soccer players.

The V˙O2max Legacy of Hill and Lupton (1923)-100 Years On.

PURPOSE: One hundred years ago, Hill and Lupton introduced the concept of maximal oxygen uptake (V˙O2max), which is regarded as "the principal progenitor of sports physiology." We provide a succinct overview of the evolvement of research on V˙O2max, from Hill and Lupton's initial findings to current debates on limiting factors for V˙O2max and the associated role of convective and diffusive components. Furthermore, we update the current use of V˙O2max in elite endurance sport and clinical settings. Practical Applications and Conclusions: V˙O2max is a healthy and active centenarian that remains a very important measure in elite endurance sports and additionally contributes as an important vital sign of cardiovascular function and fitness in clinical settings. Over the past 100 years, guidelines for the test protocols and exhaustion criteria, as well as the understanding of limiting factors for V˙O2max, have improved dramatically. Presently, possibilities of accurate and noninvasive determination of the convective versus diffusive components of V˙O2max by wearable sensors represent an important future application. V˙O2max is not only an indicator of cardiorespiratory function, fitness, and endurance performance but also represents an important biomarker of cardiovascular function and health to be included in routine assessment in clinical practice.

Effects of plyometric- and cycle-based high-intensity interval training on body composition, aerobic capacity, and muscle function in young females: a field-based group fitness assessment.

High-intensity interval training (HIIT) is an effective alternative to moderate intensity continuous training for improvements in body composition and aerobic capacity; however, there is little work comparing different modalities of HIIT. The purpose of this study was to compare the effects of plyometric- (PLYO) and cycle-oriented (CYC) HIIT on body composition, aerobic capacity, and skeletal muscle size, quality, and function in recreationally trained females. Young (21.7 ± 3.1 yrs), recreationally active females were quasi-randomized (1:1 ratio) to 8 weeks of twice weekly PLYO (n = 15) or CYC (n = 15) HIIT. Body composition (four-compartment model), VO2peak, countermovement jump performance, muscle size, and echo intensity (muscle quality), as well as strength and power of the knee extensors and plantar flexors were measured before and after training. Both groups showed a similar decrease in body fat percentage (p < 0.001; η p 2   = 0.409) and echo intensity (p < 0.001; η p 2 = 0.558), and an increase in fat-free mass (p < 0.001; η p 2   = 0.367) and VO2peak (p = 0.001; η p 2 = 0.318). Muscle size was unaffected (p > 0.05), whereas peak torque was reduced similarly in both groups (p = 0.017; η p 2 = 0.188) and rapid torque capacity was diminished only for the knee extensors after CYC (p = 0.022; d = -0.67). These results suggest that PLYO and CYC HIIT are similarly effective for improving body composition, aerobic capacity, and muscle quality, whereas muscle function may express moderate decrements in recreationally active females. ClinicalTrials.gov (NCT05821504).

Respiratory function in healthy long-term meditators: A cross-sectional comparative study.

Purpose: Respiratory function is thought to improve with long-term meditation. This study aimed to assess respiratory function in a cohort of healthy long-term meditators and non-meditators in Sri Lanka. Methods: Respiratory function of healthy, skilled long-term meditators (n = 20) practicing Buddhist meditation consistently >3 years, and age-sex matched non-meditators (n = 20) were assessed by assessing resting respiratory rate, spirometry, breath-holding time and six-minute-walk distance. Data were analyzed with SPSS-23 statistical software. Results: The long-term meditators; 45% male, mean (SD) total lifetime meditation experience 12.8 (6.5) years, aged 45.8 (8.74) years, BMI 23.68 (2.23) kgm-2, and non-meditators; 45% male, mean (SD) age 45.3 (8.05) years, BMI 23.68 (3.28) kgm-2, were comparable. Long-term meditators had slower resting respiratory rates [mean (SD); 13.35 (1.9) vs. 18.37 (2.31) breaths/minute; p < 0.001], higher peak expiratory flow rates [mean (SD); 9.89 (2.5) vs. 8.22 (2.3) L/s; p = 0.03], and higher inspiratory breath-holding times [mean (SD); 74 (29.84) vs. 53.61 (26.83) seconds, p = 0.038] compared to non-meditators. There was no significant difference in the six-minute-walk distance and estimated maximal oxygen consumption between the two groups.Resting respiratory rate of long-term meditators, showed a significant negative correlation with total lifetime meditation practice in years (r = -0.444, p = 0.049), and the average length of a meditation session per day (r = -0.65, p = 0.002). The long-term meditators with longer duration of retreat participation demonstrated lower resting respiratory rate (r = -0.522, p = 0.018) and higher tidal volumes (r = 0.474, p = 0.04). Conclusions: Long-term meditators had significantly slower resting respiratory rates and longer breath-holding times, with better spirometry parameters than non-meditators. Greater practice duration and retreat experience appear to be associated with improved resting respiratory function in long-term meditators.

Added Breathing Resistance during Exercise Impairs Pulmonary Ventilation and Exaggerates Exercise-Induced Hypoxemia Leading to Impaired Aerobic Exercise Performance.

Protective masks impose variable breathing resistance (BR) on the wearer and may adversely affect exercise performance, yet existing literature shows inconsistent results under different types of masks and metabolic demands. The present study was undertaken to determine whether added BR impairs cardiopulmonary function and aerobic performance during exercise. Sixteen young healthy men completed a graded exercise test on a cycle ergometer under the four conditions of BR using a customized breathing resistor at no breathing resistance (CON), 18.9 (BR1), 22.2 (BR2), and 29.9 Pa (BR3). The results showed that BR significantly elevates respiratory pressure (p < 0.001) and impairs ventilatory response to graded exercise (reduced VE; p < 0.001) at a greater degree with an increased level of BR which caused mild to moderate exercise-induced hypoxemia (final mean SpO2: CON = 95.6%, BR1 = 94.4%, BR2 = 91.6%, and BR3 = 90.6%; p < 0.001). Especially, such a marked reduction in SpO2 was significantly correlated with maximal oxygen consumption at the volitional fatigue (r = 0.98, p < 0.001) together with exaggerated exertion and breathing discomfort (p < 0.001). In conclusion, added BR commonly experienced when wearing tight-fitting facemasks and/or respirators could significantly impair cardiopulmonary function and aerobic performance at a greater degree with an increasing level of BR.

Complexity and pitfalls in maximal exercise testing for persons with multiple sclerosis.

BACKGROUND AND PURPOSE: Valid measurements of cardiorespiratory fitness in persons with multiple sclerosis (pwMS) are essential during inpatient rehabilitation for a precise evaluation of the current health status, for defining appropriate exercise intensities, and for evaluation of exercise intervention studies. We aim (i) to examine the proportion of pwMS who attain the American College of Sports Medicine (ACSM) criteria for maximal effort during graded cardiopulmonary exercise testing (CPET) and (ii) to provide insight into participant characteristics that limit maximal exercise performance. METHODS: This cross-sectional study comprises a retrospective examination of ACSM criteria for maximal effort during graded CPET of n = 380 inpatient pwMS (mean age = 48 ± 11 years, 66% female). Chi-squared or Fisher's exact tests were conducted to compare differences in the distribution of criteria achieved. Participants' characteristics were examined as potential predictors using binary logistic regression. RESULTS: Only 60% of the overall sample attained a respiratory exchange ratio ≥ 1.10. With regard to the definition applied, only 24% or 40% of the participants achieved an oxygen consumption plateau, and 17% or 50% attained the heart rate criterion. Forty-six percent met at least two of three criteria. Disability status, gender, disease course, and body mass index were associated with the attainment of maximal effort. CONCLUSIONS: Our findings suggest that a relevant proportion of inpatient pwMS do not attain common criteria utilized to verify maximal oxygen consumption. Identified predictors for criteria attainment can be used to create models to predict cardiorespiratory fitness and to optimize CPET protocols in restrictive groups of pwMS.

Chronic Effects of Different Intensities of Interval Training on Hemodynamic, Autonomic and Cardiorespiratory Variables of Physically Active Elderly People.

Interval training (IT) is a very efficient method. We aimed to verify the chronic effects of IT with different intensities on hemodynamic, autonomic and cardiorespiratory variables in the elderly. Twenty-four physically active elderly men participated in the study and were randomized into three groups: Training Group A (TGA, n = 8), Training Group B (TGB, n = 8) and control group (CG, n = 8). The TGA and TGB groups performed 32 sessions (48 h interval). TGA presented 4 min (55 to 60% of HRmax) and 1 min (70 to 75% of HRmax). The TGB training groups performed the same protocol, but performed 4 min at 45 to 50% HRmax and 1 min at 60 to 65% HRmax. Both training groups performed each set six times, totaling 30 min per session. Assessments were performed pre (baseline) after the 16th and 32nd intervention session. The CG performed only assessments. Hemodynamic, autonomic and cardiorespiratory (estimated VO2max) variables were evaluated. There were no significant differences between protocols and times (p > 0.05). However, the effect size and percentage delta indicated positive clinical outcomes, indicating favorable responses of IT. IT may be a strategy to improve hemodynamic, autonomic and cardiorespiratory behavior in healthy elderly people.

Importancia del VO2máx y la capacidad de recuperación de los futbolistas

El consumo máximo de oxígeno se considera un indicador directamente relacionado con la resistencia aeróbica, por lo que dicha capacidad se hace determinante en el rendimiento del futbolista. Conocer los criterios teóricos nacionales que sustentaron la importancia del VO2máx en la capacidad de recuperación en el fútbol constituyó un paso previo hacia conformar estrategias prospectivas de intervención directa para la toma de decisiones. En tal sentido, se planteó como objetivo de la investigación determinar, por consulta de especialistas, los criterios existentes de la importancia del VO2máx en la capacidad de recuperación de los futbolistas. La investigación fue descriptiva-correlacional de orientación exploratoria; se encuestaron a 13 especialistas que emitieron criterios sobre cinco indicadores. La importancia de la resistencia aeróbica en el entrenamiento del fútbol obtuvo un puntaje de (X4.62) y en relación al resto de las capacidades físicas aplicadas al fútbol un (X3.23); la importancia del VO2máx en el proceso de dirección un (X4.46); la correlación entre VO2máx y la recuperación un (X4.54) y la necesidad de perfeccionar la resistencia aeróbica en el fútbol ecuatoriano un (X4). El índice de concordancia entre especialistas obtuvo un nivel aceptable (w=0.527). Todos los indicadores de análisis obtuvieron una cualificación entre alta y muy alta, por lo que la investigación resaltó la importancia teórica brindada por los especialistas sobre el consumo máximo de oxígeno como indicador directamente relacionado con la resistencia aeróbica y el vínculo entre este y la capacidad de recuperación de los futbolistas.

SÍNTESE O consumo máximo de oxigênio é considerado um indicador diretamente relacionado à resistência aeróbica, tornando esta capacidade um fator determinante no desempenho de um jogador de futebol. Conhecer os critérios teóricos nacionais que sustentavam a importância do VO2max na capacidade de recuperação no futebol foi um passo anterior para a formação de estratégias prospectivas de intervenção direta para a tomada de decisões. Neste sentido, o objetivo da pesquisa foi determinar, consultando especialistas, os critérios existentes sobre a importância do VO2max na capacidade de recuperação dos jogadores de futebol. A pesquisa foi descritivo-correlacional com uma orientação exploratória; 13 especialistas foram pesquisados e deram critérios sobre cinco indicadores. A importância da resistência aeróbica no treinamento de futebol obteve uma pontuação de (X4,62) e em relação ao resto das capacidades físicas aplicadas ao futebol a (X3,23); a importância do VO2max no processo de gerenciamento a (X4,46); a correlação entre VO2max e recuperação a (X4,54) e a necessidade de aperfeiçoar a resistência aeróbica no futebol equatoriano a (X4). O índice de concordância entre especialistas obteve um nível aceitável (w=0,527). Todos os indicadores de análise obtiveram uma qualificação entre alto e muito alto, portanto a pesquisa destacou a importância teórica dada pelos especialistas sobre o consumo máximo de oxigênio como um indicador diretamente relacionado à resistência aeróbica e a ligação entre esta e a capacidade de recuperação dos jogadores de futebol.

The maximum oxygen consumption is considered an indicator directly related to aerobic endurance, so this capacity becomes decisive in the performance of the soccer player. Knowing the national theoretical criteria that supported the importance of VO2max in the recovery capacity in soccer was a previous step towards shaping prospective strategies of direct intervention for decision making. In this sense, the objective of the research was to determine, by consulting specialists, the existing criteria of the importance of VO2max in the recovery capacity of soccer players. The research was descriptive-correlational with an exploratory orientation; 13 specialists were surveyed who issued criteria on five indicators. The importance of aerobic endurance in soccer training obtained a score of (X 4.62) and in relation to the rest of the physical capacities applied to soccer a (X3.23); the importance of VO2max in the direction process a X 4.46); the correlation between VO2max and recovery a (X 4.54) and the need to improve aerobic endurance in Ecuadorian soccer a (X 4). The concordance index between specialists obtained an acceptable level (w=0.527). All the analysis indicators obtained a qualification between high and very high, so the research highlighted the theoretical importance provided by specialists on maximum oxygen consumption as an indicator directly related to aerobic endurance and the link between this and the ability to recovery of footballers.