Graded Exercise Test Research Articles

The Effect of High Intensity Interval Exercise on Platelet Engraftment in Autologous Bone Marrow Transplantation (BMT).

Background: Thrombocytopenia is a frequent complication after hematopoietic stem cell transplantation (HSCT). Although platelet transfusion is the most used treatment for severe thrombocytopenia, it is associated with well-established risks. High-intensity interval exercise (HIIE) results in thrombocytosis. Therefore, this study aimed to reduce thrombocytopenia by increasing platelet count through exercise. Materials and Methods: Twenty lymphoma and multiple myeloma patients were divided into HIIE and control groups. To determine the maximal exercise capacity, patients in the HIIE group performed a graded exercise test. All patients received granulocyte colony-stimulating factor for 5 days,followed by a HIIE trial. After 5 min warm up at 10 to 20% of peak power, patients in the HIIE group performed an HIIE protocol that included 12 intervals of one-minute work at 100% peak power interspersed by one-minute active rest at 20% of peak power. Patients in the control group were seated for the same duration without any physical activity. Two blood samples were taken before and immediately after the trials and were analyzed for measuring complete blood count. Results: Platelet count on the day of platelet engraftment in the HIIE group was significantly higher than in the control group (P=0.02). Single-donor platelet transfusion was significantly lower in the HIIE group than in the control group (P=0.05). Conclusion: Based on the findings of the present study, a short bout of HIIE had a positive effect on platelet engraftment through thrombocytosis and reduced platelet transfusion and its complications, which could be a useful strategy for HSCT patients.

Sixweeks of localized passive heat therapy elicits some exercise-like improvements in resistance artery function.

The purpose of this study was to examine the effects of 6weeks of localized, muscle-focused (quadriceps femoris) passive heat therapy (PHT) on resistance artery function, exercise haemodynamics and exercise performance relative to knee extension (KE) exercise training (EX). We randomized 34healthy adults (ages 18-36; n=17 female, 17male) to receive either PHT or sham heating sessions (120min, 3days/week), or EX (40min, 3days/week) over 6weeks. Blood flow was assessed with Doppler ultrasound of the femoral artery during both passive leg movement (PLM) and a KE graded exercise test. Muscle biopsies were taken from the vastus lateralis at baseline and after 6weeks. Peak blood flow during PLM increased to the same extent in both the EX (∼10.5% increase, P=0.009) and PHT groups (∼8.5% increase, P=0.044). Peak flow during knee extension exercise increased in EX (∼19%, P=0.005), but did not change in PHT (P=0.523) and decreased in SHAM (∼7%, P=0.020). Peak vascular conductance during KE increased by ∼25% in EX (P=0.030) and PHT (P=0.012). KE peak power increased in EX by ∼27% (P=0.001) but did not significantly change in PHT and SHAM groups. Expression of endothelial nitric oxide synthase increased significantly in both EX (P=0.028) and PHT (P=0.0095), but only EX resulted in increased angiogenesis. In conclusion, 6weeks of localized PHT improved resistance artery function at rest and during exercise to the same extent as exercise training but did not yield significant improvements in performance. KEY POINTS: Many for whom exercise would be most beneficial are either unable to exercise or have a very low exercise tolerance. In these cases, an alternative treatment to combat declines in resistance artery function is needed. We tested the hypothesis that passive heat therapy (PHT) would increase resistance artery function, improve exercise haemodynamics and enhance exercise performance compared to a sham treatment, but less than aerobic exercise training. This report shows that 6weeks of localized PHT improved resistance artery function at rest and during exercise to the same extent as exercise training but did not improve exercise performance. Additionally, muscle biopsy analyses revealed that endothelial nitric oxide synthase expression increased in both PHT and exercise training groups, but only exercise resulted in increased angiogenesis. Our data demonstrate the efficacy of applying passive heat as an alternative treatment to improve resistance artery function for those unable to receive the benefits of regular exercise.

Assessing the Validity of Two Non-Exercise Regression Equations for Predicting Maximal Oxygen Consumption

ABSTRACT Purpose: This study aimed to develop two regression equations to predict maximal oxygen consumption (VO2max) using non-exercise data from a substantial cohort of healthy Iranian adult males. Additionally, this study sought to examine the predictive accuracy of these equations across four different levels of physical activity. Methods: A total of 126 participants (age: 34.9 ± 11.3 years, body mass index [BMI]: 24.9 ± 2.7 kg/m², and body fat percentage [BF%]: 18.3 ± 4.9) completed a maximal graded exercise test to measure VO2max, with a mean of 45.0 ± 3.4 ml.kg−1.min−1. Participants also provided information on age, current physical activity rating (PA-R), and either BMI or BF% to estimate VO2max using Jackson and colleagues’ regression equations. The PA-R was assessed via a standardized questionnaire and categorized into four levels: sedentary, low, moderate, and high. Results: The key findings from this study indicate that both original models significantly underestimated actual VO2max in a large cohort of Iranian adults (both, p < .001 and mean differences exceeding 2.19 ml.kg−1.min−1). Nevertheless, these models provided accurate predictions for VO2max among individuals with moderate levels of physical activity (both, p > .08 and mean differences between 0.51 and 1.03 ml.kg−1.min−1). Furthermore, the models demonstrated moderate validity, as evidenced by an intraclass correlation coefficient (ICC) of 0.841 and a coefficient of variation averaging 10.9%, with a range from 8.5% to 13.6%. Conclusions: While Jackson’s two non-exercise models showed limited accuracy in predicting VO2max among Iranian healthy male adults, they exhibited reasonable precision, particularly among moderately active men.

The Age Factor in Cardiac Rehabilitation

Coronary artery disease (CAD) is a major global cause of death, and its risk increases with age. This study investigates the relationship between age, patient characteristics, and rehabilitation outcomes in the cardiac rehabilitation (CR) of CAD. A cross-sectional study analyzed 60 medical records of post-coronary artery bypass graft (CABG) or post-percutaneous coronary intervention (PCI) patients who underwent a 6-week CR program after a graded exercise test using the Modified Bruce Protocol. The CR consists of 90% male participants, with an average age of 59.25 ± 6.69 years and an overweight body mass index. CR increases metabolic equivalents in all subjects, while age has a weakly significant negative correlation with the result of CR, so it can be concluded that CR is advantageous for older post-CABG or post-PCI patients.

Practical Management: A Standardized Aerobic Exercise Program for Adolescents With Concussion in the Absence of Graded Exercise Testing: Erratum.

Practical Management: A Standardized Aerobic Exercise Program for Adolescents With Concussion in the Absence of Graded Exercise Testing: Erratum.

Antioxidant and neurodevelopmental gene polymorphisms in prematurely born individuals influence hypoxia-related oxidative stress

Preterm born (PTB) infants are at risk for injuries related to oxidative stress. We investigated the association between antioxidant and neurodevelopmental gene polymorphisms and oxidative stress parameters in PTB male young adults and their term-born counterparts at rest and during exercise. Healthy young PTB (N = 22) and full-term (N = 15) males underwent graded exercise tests in normobaric normoxic (FiO2 = 0.21) and hypoxic (FiO2 = 0.13) conditions. CAT rs1001179 was associated with decrease in nitrites in the whole group and in PTB individuals (P = 0.017 and P = 0.043, respectively). GPX1 rs1050450 was associated with decrease in ferric reducing antioxidant power in the whole group and in full-term individuals (P = 0.017 and P = 0.021, respectively). HIF1A rs11549465 was associated with decrease in nitrotyrosine and increase in malondialdehyde (P = 0.022 and P = 0.018, respectively). NOTCH4 rs367398 was associated with increase in advanced oxidation protein products and nitrites (P = 0.002 and P = 0.004, respectively) in hypoxia. In normoxia, NOTCH4 rs367398 was associated with increase in malondialdehyde in the whole group (P = 0.043). BDNF rs6265 was associated with decreased nitrites/nitrates in the whole group and in PTB individuals (P = 0.009 and P = 0.043, respectively). Polymorphisms in investigated genes and PTB might influence oxidative stress response after exercise in normoxic or hypoxic conditions far beyond the neonatal period in young male adults.

Valoración fisiológica y manejo de pacientes post-COVID con pruebas funcionales cardiopulmonares y de imagen normales

ObjectiveContributing to elucidate the pathophysiology of dyspnoea and exertion intolerance in post-COVID syndrome patients with normal cardiopulmonary imaging and functional tests at rest, while determining their fitness and level of endurance in order to individualize working parameters for physical rehabilitation. Material and methodsAfter an anamnesis and clinical examination at rest, 27 subjects (50±11.9 years) (14 women) with post-COVID syndrome of more than 6 months of evolution performed a continuous maximal-incremental graded cardiopulmonary exercise test (CPET) with breath-by-breath gas-exchange monitoring and continuous ECG registration, on an electromagnetically braked cycle ergometer. The values obtained were compared with those of reference, gender or controls, using the Chi-square, t-Student or ANOVA test. ResultsThe clinical examination at rest and the CPET were clinically normal and without adverse events. Reasons for stopping exercise were leg discomfort. It is only worth noting a BMI=29.9±5.8kg/m2 and a basal lactate concentration of 2.1±0.7mmol/L. The physiological assessment of endurance showed the following results relative to predicted VO2máx: 1)peakVO2=80.5±18.6%; 2)VO2 at ventilatory threshold1 (VO2VT1): 46.0±12.9%; 3)VO2VT2: 57.2±16.4%; 4)working time in acidosis: 5.6±3,0minutes; and 5)maximum lactate concentration: 5.1±2.2mmol/L. ConclusionsThe CPET identified limited aerobic metabolism and early increase in glycolytic metabolism as causes of dyspnoea and exercise intolerance, determined fitness for physical rehabilitation, and individualized it based on the level of endurance.

Evaluation of Nutrition and Performance Parameters in Division 1 Collegiate Athletes.

Testing and evaluating athletes is necessary and should include performance, body composition, and nutrition. The purpose of this study was to report assessments of dietary intake, V˙O2max, and body composition in D1 collegiate athletes and examine relationships between these assessments. Dietary intake was assessed with 3-day recalls and compared to recommendations, and body composition was assessed via bioelectrical impedance analysis (BIA) (n = 48). V˙O2max was evaluated using a graded exercise test (GXT) with a verification bout (n = 35). Reliability between "true" V˙O2max and verification was determined. Correlations and regressions were performed. Energy, carbohydrate, and micronutrient intake was lower than recommendations. Mean V˙O2max was 47.3 and 47.4 mL·kg-1·min-1 for GXT and verification, respectively. While correlations were apparent among dietary intake, V˙O2max, and body composition, percent fat-free mass (%FFM) predicted 36% of V˙O2max. Collegiate athletes are not meeting energy and carbohydrate recommendations and exceed fat recommendations. Vitamin D and magnesium were low in all sports, and iron and calcium were low in females. V˙O2max ranged from 35.6 to 63.0 mL·kg-1·min-1, with females below average and males meeting typical values for their designated sport. Assessing D1 athletes can provide guidance for sports dietitians, coaches, and strength and conditioning specialists to track and monitor nutrition in athletes.

Comparison of time-motion, heart rate responses, and training load measurement in Brazilian jiu-jitsu heavyweight and lightweight fighters: a cross-sectional study

ABSTRACT This study compares technical-tactical and physiological parameters between lightweight and heavyweight male Brazilian Jiu-Jitsu (BJJ) fighters. We included 11 adult BJJ fighters (lightweight: age = 28 ± 7 years; body mass = 73 ± 2 kg; height = 1.72 ± 0.7 m; body mass index = 25 ± 2 kg/m2; heavyweight: age = 27 ± 3 years; body mass = 95 ± 6 kg; height = 1.87 ± 0.6 m; body mass index = 27 ± 2 kg/m2). Six participants were considered lightweight (71 to 77 kg) and five heavyweight divisions (88 to 101 kg). Initially, sample characteristics and a graded exercise test determined the physiological parameters. A simulated competition (10 minutes maximum) assessed technical-tactical characteristics, Heart Rate (HR), Rate of Perceived Exertion (RPE), TRaining IMPulse based on HR, session-RPE, and time at HR intensity zones (Z1, Z2, and Z3). A comparison test revealed that heavyweight athletes exhibited a higher height, body mass, total time in low-intensity efforts per block, number of standing combat blocks, and less time in high-intensity efforts per block and lower VO2MAX than lightweight (p < 0.05). The HR showed a nonlinear increase throughout each minute of the fights, with the heavyweight division demonstrating predominantly higher HR values. All fighters accumulated more time in training zone 3. The physiological and temporal differences between divisions suggest that BJJ training must be designed specifically for lightweight or heavyweight divisions.

Order effect of an 8-week concurrent training program on the maximal fat oxidation

BackgroundConcurrent training (CT) is a common method used in health-oriented training programs. However, its design needs to be explored in order to inform practitioners about the most effective methods to improve different health-related markers (e.g., maximal fat oxidation [MFO]). Thus, this study aims to determine the order effect of an 8 week CT on the MFO of recreationally trained young adults.MethodsTwenty participants were allocated in two different groups to perform the CT differing only in the exercise sequence. The endurance training (ET) consisted of 4 to 6 repetitions of 30 s all-out running sprints with 4 min of active recovery. The resistance training (RT) consisted of 4 to 6 sets at 60 to 80% of the one-repetition maximum with 5 to 1 repetition in reserve of back squat and bench press exercises. 15 min of rest were established between exercise modes. Previous and after the CT program, participants performed a graded exercise test where MFO was determined.ResultsThere was a significant time effect on MFO (p = 0.044). A moderate increase was observed in both ET + RT (Mean change: 0.11 [− 0.02 to 0.25] g/min; Effect size: 0.61 [− 0.12 to 1.35]) and RT + ET (Mean change: 0.07 [− 0.01 to 0.16] g/min; Effect size: 0.62 [− 0.12 to 1.36]) groups. No significant interaction was observed (p = 0.658).ConclusionsThe 8 week CT program improved the muscle oxidative capacity of recreationally trained young adults regardless of the exercise sequence.

Timing matters: diurnal variation of maximal fat oxidation and substrate oxidation rates in metabolic syndrome-a randomized crossover study.

The aim of this study was to investigate if diurnal oscillation in maximal fat oxidation (MFO) and substrate oxidation rates during exercise exists in subjects with metabolic syndrome (MetS). In a randomized crossover design, 14 MetS patients were assigned to two graded exercise tests conditions performed in the morning (between 7:00 and 9:00 a.m) and in the afternoon (between 4:00 and 5:00 p.m). MFO was defined as the highest absolute value of fat oxidation obtained from the average of last 2-min stages during an indirect calorimetry test. MFO increased by 20.6% from morning to afternoon (p = 0.0002, Cohen's d = 0.52). There was a significant time of day, (p < 0.0001, η2p = 0.76) and intensity effect (p = 0.002, η2p = 0.32) in fat oxidation (Fatox) rates indicating that Fatox was higher in the afternoon than in the morning. Our study extends previous findings on the existence of diurnal variation in maximal fat oxidation to MetS patients, highlighting the afternoon as a more favorable time for fat utilization during exercise. These findings have practical implications for optimizing training timing in MetS patients. PACTR202306776991260.

Optimizing Short Sprint Interval Training for Young Soccer Players: Unveiling Optimal Rest Distributions to Maximize Physiological Adaptations.

Present study aimed to compare the effects of SSIT intervention with varying rest distributions on hormonal, physiological, and performance adaptations in soccer players. Thirty-six players were randomly divided into three SSIT groups, each performing 4 sets of 6-10 repetitions of 6-second all-out running with rest intervals at ratios of 1:3, 1:6, and 1:9. Prior to and following the 7-week training period, aerobic fitness indices and anaerobic power were evaluated using a graded exercise test with a gas collection system and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring vertical jump, 20-m sprint, and T-test change of direction speed, Yo-Yo IR1 and maximal kicking distance. Hormonal status was also monitored by evaluating testosterone and cortisol levels. Following the 7-week training period, all SSIT interventions resulted in significant enhancements (p < 0.05) in soccer-related performance, physiological parameters, and hormonal adaptations, exhibiting effect sizes that ranged from small to large. Comparative analysis indicated that the 1:9 SSIT results in greater adaptive responses (p < 0.05) in the vertical jump, peak power, testosterone, and cortisol compared to the 1:3 SSIT group. By contrast, the 1:3 SSIT group induced more adaptive responses (p < 0.05) in the mean power output, maximum oxygen consumption (V̇O2max), and Yo-Yo IR1 compared to the 1:9 SSIT group. Hence, for enhancing physical performance, especially vertical jump height, anaerobic peak power, and hormonal adaptations, the 1:9 SSIT ratio is preferable. Conversely, shorter rest intervals (specifically, the 1:3 SSIT ratio) are better suited for eliciting heightened adaptive responses in mean power output, V̇O2max, and Yo-Yo IR1 over the 7-week training period among young male soccer players.

Oxygen uptake efficiency slope in 8- to 12-year-old boys and girls.

Oxygen uptake efficiency slope (OUES) is an objective physiological measure that can be obtained from a standard graded exercise test. However, there is conflicting evidence regarding sex differences in OUES values in children. Therefore, this study investigated potential sex differences in absolute, ratio-scaled, and allometrically scaled OUES in 8.0- to 12.0-year-old children. Retrospective and prospective data of 18 boys and 22 girls were utilized. All participants had undergone familiarization before performing a maximal cycle ergometer test to determine OUES. These values were also ratio-scaled and allometrically scaled to mass and body surface area (BSA). Group differences were tested via independent sample t-tests (or Mann-Whitney U if not normally distributed). Absolute OUES values (VO<inf>2</inf> mL∙min-1/log<inf>10</inf>VE L∙min-1) were significantly higher in boys compared to girls (1860.8±359.3 vs. 1514.3±212.6). When scaled to mass (VO<inf>2</inf> mL∙kg-1∙min-1/log<inf>10</inf>VE L∙kg-1∙min-1), OUES was no longer significantly different between groups, but when scaled to BSA (VO<inf>2</inf> mL∙m-2∙min-1/log<inf>10</inf>VE L∙m-2∙min-1), OUES was significantly higher in the boys than the girls (1414.4±204.2 vs. 1268.9±134.6). When allometry was applied for mass (OUES/mass0.444) boys had significantly higher value than girls (350.8±46.7 vs. 305.0±31.5). The present study demonstrated that boys had greater OUES values scaled to BSA and allometrically scaled to body mass. These findings provide further evidence of sex differences with OUES values in preadolescent children and implies the need for sex-specific reference values prior to using OUES for the assessment of cardiorespiratory pathology in children.

남자 운동선수들의 최대운동부하검사에 따른 심박수 회복률 비교

남자 운동선수들의 최대운동부하검사에 따른 심박수 회복률 비교

Autonomic Rebound Following Maximal Exercise in Bodybuilders and Recreationally Active Participants.

The off-season for natural bodybuilders (BB) is characterized by increased training loads and fluctuations in caloric intake, which may lead to insufficient recovery. The autonomic nervous system (ANS) plays a pivotal role in recovery. The purpose of this study was to evaluate resting ANS activity and recovery following a maximal exercise bout in off-season BB and compare them to those of recreationally active individuals. Fifteen males participated; 7 recreationally active (RA) (24.6 ± 2.1 years, 81.1 ± 10.8 kg) and 8 BB (21.8 ± 2.9 years, 89.3 ± 13.0 kg). Each performed a graded exercise test. Heart rate variability (HRV) was measured at rest and during a 45 min recovery period. HRV was analyzed as: root mean square of successive differences (lnRMSSD), standard deviation of normal-to-normal sinus beats (lnSDNN), high frequency (lnHF), low frequency (lnLF), and the ratio of low frequency to high frequency (lnLF/lnHF). A one-way ANOVA showed no differences for any resting marker of HRV, HR, and HR recovery. A significant depression in all markers of HRV was observed in the BB group at the 15 min point, and no recovery was observed before 45 min when compared to RA. The results of this study demonstrated depressed HRV recovery following the graded exercise test in BB when compared to the RA group.

Metabolic equivalents intensity thresholds for physical activity classification in older adults

BackgroundAlthough the metabolic equivalents (METs) system is a common procedure to quantify the intensity of physical activity in older adults, it remains unclear whether the conventional METs intensity thresholds (CTs) used for this purpose are appropriate in this population. Therefore, this study aimed (i) to derive overall and fitness-specific METs intensity thresholds in older adults ≥ 60 years old (OATs) expressed both in standard METs (VO2/3.5 mL O2·kg−1·min−1) and older adults METs60+ (VO2/2.7 mL O2·kg−1·min−1), and (ii) to compare them with the CTs.MethodsA total of 93 subjects were assessed for cardiorespiratory fitness. Graded exercise test protocols using indirect calorimetry were performed to calculate individual VO2max and categorize subjects as "very poor/fair" or "good/superior" fitness. Overall and fitness-specific OATs expressed in standard METs (OATsstandard) and METs60+ (OATs60+) were derived based on the %VO2max and the ventilatory thresholds (VTs) physical intensity categories.ResultsSignificantly higher VO2max, VO2 at VT1 and VO2 at VT2 (p < 0.001) were obtained in the "good/superior" subgroup compared to the "very poor/fair" fitness subgroup. Accordingly, OATs were approximately 69% higher in individuals with a "good/superior" fitness compared to those with a "very poor/fair" fitness. Furthermore, this study showed that OATsstandard were approximately 21–24% lower than OATs60+, and 10–22% higher OATs were observed when following the VTs intensity categories (heavy-intensity physical activity [HPA] and severe-intensity physical activity [SPA]) compared to the %VO2max categories (moderate-intensity physical activity [MPA] and vigorous-intensity physical activity [VPA]). When compared with the CTs, similar or higher OATsstandard and OATs60+ for MPA, and HPA were obtained compared to the conventional MPA threshold (3.0 METs). Conversely, for VPA and SPA, lower, similar, or higher OATs were obtained depending on the METs derivation approach (OATsstandard or OATs60+) or the intensity categories (VO2max or VTs), compared to the conventional VPA threshold (6.0 METs).ConclusionsNone of the derived OATs were concurrently similar to the CTs, suggesting that fitness-specific METs intensity thresholds adapted to the METs derivation approach should be used in older adults.Trial registrationFenotipAGING (Non-health-care intervention study), PRO-Training (NCT05619250).

Identifying physiological determinants of 800 m running performance using post-exercise blood lactate kinetics

PurposeThe aims of the present study were to investigate blood lactate kinetics following high intensity exercise and identify the physiological determinants of 800 m running performance.MethodsFourteen competitive 800 m runners performed two running tests. First, participants performed a multistage graded exercise test to determine physiological indicators related to endurance performance. Second, participants performed four to six 30-s high intensity running bouts to determine post-exercise blood lactate kinetics. Using a biexponential time function, lactate exchange ability (γ1), lactate removal ability (γ2), and the quantity of lactate accumulated (QLaA) were calculated from individual blood lactate recovery data.Results800 m running performance was significantly correlated with peak oxygen consumption (r = −0.794), γ1 and γ2 at 800 m race pace (r = −0.604 and −0.845, respectively), and QLaA at maximal running speed (r = −0.657). V˙\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\dot{\ ext{V}}}$$\\end{document}O2peak and γ2 at 800 m race pace explained 83% of the variance in 800 m running performance.ConclusionOur results indicate that (1) a high capacity to exchange and remove lactate, (2) a high capacity for short-term lactate accumulation and, (3) peak oxygen consumption, are critical elements of 800 m running performance. Accordingly, while lactate has primarily been utilized as a performance indicator for long-distance running, post-exercise lactate kinetics may also prove valuable as a performance determinant in middle-distance running.

Neural mechanisms of the relationship between aerobic fitness and working memory in older adults: An fNIRS study

Abstract A growing number of studies have revealed that higher aerobic fitness is associated with better working memory (WM) performance in older adults. However, the underlying functional neural mechanisms of this association remain under debate. It has been reported that aging increases recruitment of the prefrontal cortex (PFC) during cognitive tasks, and that this is associated with task performance in a compensatory manner. Therefore, this study aimed to clarify the prefrontal activation pattern that is associated with the relationship between aerobic fitness and WM performance in older adults, focusing on age-related extended prefrontal recruitment. Forty-seven older adults (65–74 years, 29 females) and 49 younger adults (18–24 years, 23 female) performed verbal and spatial n-back tasks, which included 0-, 1-, and 2-back conditions. Reaction time (RT) and accuracy (ACC) were assessed as indices of task performance. Prefrontal activation during the experimental tasks was monitored using functional near-infrared spectroscopy (fNIRS) and analyzed using an adaptive GLM method. We compared task performance and prefrontal activation between age groups to find age-related prefrontal activation patterns. Only older adults underwent a graded exercise test (GXT) to determine their ventilation thresholds (VT) as a measure of aerobic fitness, and, subsequently, the relationships among aerobic fitness, n-back task performance, and prefrontal activation in older adults were examined using correlation analysis and mediation analysis controlling for possible covariates. A comparison of task performance between groups revealed that older adults had slower RT and lower ACC than did younger adults, especially in the higher WM load 2-back condition. Group comparisons of prefrontal activation showed that older adults exhibited additional or greater activation than younger adults mainly in the ventrolateral PFC (VLPFC) and front polar area (FPA) in both the verbal and spatial 2-back conditions. Correlation analysis showed a relationship between higher VT, shorter RT for the verbal 2-back condition, and greater prefrontal activation of the bilateral FPA and right VLPFC during verbal 2-back conditions in older adults. In addition, mediation analyses indicated the possibility of a mediation effect of the prefrontal activation on the relationship between VT and RT for the verbal 2-back condition. These results suggest that older adults with higher aerobic fitness levels recruited more extended PFC regions, possibly for compensatory activation, to enhance their performance of the verbal n-back task. This study sheds light on the neural mechanisms underpinning the relationship between aerobic fitness and cognitive function in older adults.

Are incremental exercise relationships between rating of perceived exertion and oxygen uptake or heart rate reserve valid during steady-state exercises?

Rating of perceived exertion (RPE) is considered a valid method for prescribing prolonged aerobic steady-state exercise (SSE) intensity due to its association with physiological indicators of exercise intensity, such as oxygen uptake (V̇O2) or heart rate (HR). However, these associations between psychological and physiological indicators of exercise intensity were found during graded exercise tests (GXT) but are currently used to prescribe SSE intensity even though the transferability and validity of the relationships found during GXT to SSE were not investigated. The present study aims to verify whether (a) RPE-HR or RPE-V̇O2 relations found during GXTs are valid during SSEs, and (b) the duration and intensity of SSE affect these relations. Eight healthy and physically active males (age 22.6 ± 1.2 years) were enrolled. On the first visit, pre-exercise (during 20 min standing) and maximal (during a GXT) HR and V̇O2 values were measured. Then, on separate days, participants performed 4 SSEs on the treadmill by running at 60% and 80% of the HR reserve (HRR) for 15 and 45 min (random order). Individual linear regressions between GXTs' RPE (dependent variable) and HRR and V̇O2 reserve (V̇O2R) values (computed as the difference between maximal and pre-exercise values) were used to predict the RPE associated with %HRR (RPEHRR) and %V̇O2R (RPEV̇O2R) during the SSEs. For each relation (RPE-%HRR and RPE-%V̇O2R), a three-way factorial repeated measures ANOVA (α=0.05) was used to assess if RPE (dependent variable) was affected by exercise modality (i.e., RPE recorded during SSE [RPESSE] or GXT-predicted), duration (i.e., 15 or 45 min), and intensity (i.e., 60% or 80% of HRR). The differences between RPESSE and GXT-predicted RPE, which were assessed by evaluating the effect of modality and its interactions with SSE intensity and duration, showed no significant differences between RPESSE and RPEHRR. However, when RPESSE was compared with RPEV̇O2R, although modality or its interactions with intensity were not significant, there was a significant (p=0.020) interaction effect of modality and duration yielding a dissociation between changes of RPESSE and RPEV̇O2R over time. Indeed, RPESSE did not change significantly (p=0.054) from SSE of 15 min (12.1 ± 2.0) to SSE of 45 min (13.5 ± 2.1), with a mean change of 1.4 ± 1.8, whereas RPEV̇O2R decreased significantly (p=0.022) from SSE of 15 min (13.7 ± 3.2) to SSE of 45 min (12.4 ± 2.8), with a mean change of -1.3 ± 1.5. The transferability of the individual relationships between RPE and physiological parameters found during GXT to SSE should not be assumed as shown by the results of this study. Therefore, future studies modelling how the exercise prescription method used (e.g., RPE, HR, or V̇O2) and SSE characteristics (e.g., exercise intensity, duration, or modality) affect the relationships between RPE and physiological parameters are warranted.

THE ACUTE EXERCISE-INDUCED INFLAMMATORY RESPONSES IN GASTROINTESTINAL DISORDERS

INTRODUCTION &amp; AIMS Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), are characterised by intestinal inflammation that presents severe symptoms and continued complications throughout the lifespan. These gastrointestinal (GI) disorders have a growing prevalence worldwide with no known cure. Management strategies often require a ‘trial and error’ process before an effective pharmacal/s is established; the successful interim varies considerably with prevalent adverse side-effects and gradual decline in the effectiveness of medication. Accordingly, alternative mechanisms to complement management options, reduce side-effects, and improve well-being warrant investigation. Physical activity is known to be beneficial for a variety of inflammatory conditions; the advantageous effects are associated with the exercise-induced inflammatory response directly from active muscle tissue. Despite this knowledge, minimal studies have attempted to quantify the inflammatory effect of exercise. This study investigates the inflammatory response of acute exercise. METHODS Participants were allocated into one of two groups: GI disorders (IBD &amp; IBS; n = 11) or apparently healthy control (AHC; n = 11). All participants completed three sessions: 1) initial familiarisation: questionnaires, anthropometry measures, DEXA scan, and a graded exercise test; 2) protocol 1: moderate-intensity continuous exercise; and 3) protocol 2: alternating high- and low-intensity exercise. Participants were randomly allocated to the acute exercise protocols. Each protocol had a fasted pre-exercise venous blood sample, 35-minutes cycle, fasted blood sample immediately post-, 2hrs post-, and 24hr post-exercise. RESULTS Significant differences were observed between groups in body mass index, waist and hip circumstances, percentage of fat mass, and VO2peak (p &amp;lt; .05). Analyses of venous blood samples will be presented. CONCLUSION With no known cure, lifestyle management is important for those with GI disorders. Exercise hosts several benefits; however, given the inflammatory nature of the condition, the acute responses of exercise are important for clinicians working with IBD/IBS patients.