Cycle Ergometer Exercise Test Research Articles

Comparison between treadmill and bicycle ergometer exercise tests in mild-to-moderate hypertensive Nigerians.

BackgroundComparative cardiovascular responses to treadmill and bicycle ergometer (bike) exercise tests in hypertensive Nigerians are not known. This study compared cardiovascular responses to the two modes of exercise testing in hypertensives using maximal exercise protocols.MethodsOne hundred and ten male subjects with mild-to-moderate hypertension underwent maximal treadmill and bike test one after the other at a single visit in a simple random manner. Paired-sampled t-test was used to compare responses to both exercise tests while chi-squared test was used to compare categorical variables.ResultsThe maximal heart rate (P<0.001), peak systolic blood pressure (P=0.02), rate pressure product (P<0.001), peak oxygen uptake (P<0.001), and exercise capacity (P<0.001) in metabolic equivalents were signifcantly higher on the treadmill than on the bike.ConclusionHigher cardiovascular responses on treadmill in Nigerian male hypertensives in this study, similar to findings in non-hypertensives and non-Nigerians in earlier studies, suggest that treadmill may be of better diagnostic utility in our population.

Associations of cardiorespiratory fitness, physical activity, and adiposity with arterial stiffness in children.

Associations of cardiorespiratory fitness (CRF), physical activity (PA), sedentary behavior, and body fat percentage (BF%) with arterial stiffness and dilation capacity were investigated in 160 prepubertal children (83 girls) 6-8 years of age. We assessed CRF (watts/lean mass) by maximal cycle ergometer exercise test, total PA, structured exercise, unstructured PA, commuting to and from school, recess PA and total and screen-based sedentary behavior by questionnaire, BF% using dual-energy X-ray absorptiometry, and arterial stiffness and dilation capacity using pulse contour analysis. Data were adjusted for sex and age. Poorer CRF (standardized regression coefficient β = -0.297, P < 0.001), lower unstructured PA (β = -0.162, P = 0.042), and higher BF% (β = 0.176, P = 0.044) were related to higher arterial stiffness. When CRF, unstructured PA, and BF% were in the same model, only CRF was associated with arterial stiffness (β = -0.246, P = 0.006). Poorer CRF was also related to lower arterial dilation capacity (β = 0.316, P < 0.001). Children with low CRF (< median) and high BF% (≥ median; P = 0.002), low CRF and low unstructured PA (< median; P = 0.006) or children with low unstructured PA and high BF% (P = 0.005) had higher arterial stiffness than children in the opposite halves of these variables. Poor CRF was independently associated with increased arterial stiffness and impaired arterial dilation capacity among children.

Estrogen Receptor-beta Gene Polymorphism Affects Cardiorespiratory Fitness In Japanese Women

Estrogen affects energy metabolism via upregulation of mitochondrial biogenesis and angiogenesis in muscular tissue. Recently, it was reported that TT genotype of rs1271572 of estrogen receptor-beta (ESR2) gene resulted in reduction of the transcription activity in the ESR2. Therefore, the ESR2 gene polymorphism may have potential impacts on cardiorespiratory fitness. However, the effect of the ESR2 genotype (rs1271572) on the cardiorespiratory fitness and gender difference of influence with the genotype remain unclear. PURPOSE: To determine the effect of ESR2 gene polymorphism (rs1271572) on cardiorespiratory fitness and gender difference of influence with the genotype in the Japanese adults. METHODS: Two hundred sixty Japanese men (19-85 yrs, average age; 45.6±17.2 yrs, mean±SD) and six hundred six women (18-84 yrs, average age; 48.7±16.4 yrs) participated in a cross-sectional study. ESR2 (rs1271572, G>T; transposition in the promoter region) polymorphism was determined by real-time PCR with Taqman probe. As an index of cardiorespiratory fitness, we measured peak oxygen uptake (VO2peak) during an incremental cycle ergometer exercise test. RESULTS: No significant differences in the allelic frequencies of the polymorphism was detected between the genders (men: G allele=0.57; women: G allele=0.60), and these frequencies also did not deviate from the predicted Hardy-Weinberg equilibrium. In women, the VO2peak of individuals with the TT genotype of rs1271572 were significantly lower than those of other genotypes (GG; 32.0±7.5, GT; 30.8±6.9, TT; 29.8±7.5 ml/kg/min., mean ±SD) after adjustment for confounders such as smoking status, drug-taking status and %fat. However, no differences of VO2peak among the genotypes were observed in men (GG; 37.0±10.7, GT; 36.6±9.6, TT; 36.6±8.8 ml/kg/min.). CONCLUSIONS: TT genotype of ESR2 gene (rs1271572) is associated with lower cardiorespiratory fitness in Japanese women but is not associated in men. These results suggest that the effect of the ESR2 genotype on the cardiorespiratory fitness is differed between genders.

Metabolic Syndrome, Brachial Artery Diameter and Cardiorespiratory Fitness - The DR’s EXTRA Study

The metabolic syndrome (MetS) is characterized by a systemic arterial remodeling which can be proved by a large brachial artery diameter (BAD). The arterial enlargement may result, however, also from long-term endurance-type physical activity (PA). PURPOSE: To study whether the association of a large BAD with prevalence of MetS can be further defined by allowing for the cardiorespiratory fitness as a proxy variable for long-term endurance-type PA. METHODS: The subjects were a population-based sample of 593 men and 583 women aged 57-78 years who participated in the DR’s EXTRA Study. Metabolic syndrome was determined by the NCEP criteria. The end-diastolic BAD was assessed by ultrasound and cardiorespiratory fitness as peak oxygen uptake (VO2peak) achieved in a maximal cycle ergometer exercise test. Age-adjusted linear regression analysis was used to compare the means of BAD in those with or without MetS. For the main analyses, sex-spesific tertiles of BAD and VO2peak were pooled in age-adjusted logistic regression analyses and the association was explored after the highest tertile of BAD (>4.25 mm in men, >3.36 mm in women) was further categorized according to tertiles of VO2peak (low ≤23.3 and high >28.9 ml/kg/min in men; low ≤18.4 and high >22.8 ml/kg/min in women). RESULTS: Mean BAD was higher in 323 (27%) subjects with MetS compared to those without MetS (3.80 vs. 3.63 mm, p<0.001 for difference between groups). Subjects (n=141) with a large BAD and a low VO2peak had an increased risk of having MetS (OR 5.1 [95% confidence interval, CI, 3.5-7.6], p<0.001) compared to subjects with narrower BAD (the two lowest tertiles). Additionally, 123 subjects with a large BAD but a high VO2peak had a decreased risk of having MetS (OR 0.4 [95% CI 0.2-0.8], p=0.004) compared to subjects with narrower BAD. The results were similar when assessed separately in men and women. CONCLUSION: The group with a large BAD includes subjects with unfavourable vascular risk factor profile judged by an increased risk of having MetS, but also subjects with a decreased risk of having MetS. These groups can be identified based on cardiorespiratory fitness. A large BAD should not be interpreted unambiguously as an unfavourable finding from viewpoint of vascular health without considering whether it may result from long-term endurance-type PA as well.

Obtaining a formula that improves maximum oxygen consumption estimation in cycle ergometer exercise tests

ObjectivesTo evaluate if the estimation of the maximal oxygen consumption (MO2C) in METs (metabolic equivalents) by means of the table proposed in the guidelines of the Spanish Society of Cardiology is a sufficiently reliable method when applied to the bicycle exercise test. Material and methodsThe MO2C in METs was obtained by gas-exchange analysis on bicycle ergometer tests in 97 healthy subjects (group I). It was compared with the estimate of METs using the table in which only watts and patient's weight were included. A better-adjusted formula was validated in 289 subjects with normal exercise myocardial perfusion gated-SPECT (group II) using the introduction of clinical and ergometric variables. ResultsIn group I individuals a good correlation between METs estimated with the table and those obtained through gas-exchange analysis (CCI: 0.93) was observed. However, the best adjusted formula to estimate METs in group II subjects included watts, body mass index (BMI), age and gender (METS=11.820−0.054×age−0.189×BMI+1.031×gender+0.020×watts) (women: 0, men: 1). This formula allowed the reclassification of 46.9% of group ii subjects into the category <5METs versus the estimation by table. ConclusionsEstimating the METs with the conventional table is reliable. However, the best adjustment in subjects with normal bicycle exercise SPECT was obtained when, in addition to watts and BMI, age and gender were also considered.

The Effect of Habitual Physical Training on Left Ventricular Function During Exercise Assessed by Three-Dimensional Echocardiography.

Stroke volume (SV) in trained athletes continuously increases with progressive exercise intensity. We studied whether physical training affected left ventricle (LV) function response to exercise using 3D echocardiography and tissue Doppler imaging (TDI). Eleven male university athletes and 12 male university nonathletes were enrolled in this study. After baseline data were collected, subjects performed a symptom-limited supine bicycle ergometer exercise test. Initial workload was 25Watts (W) and increased 25W every 3minutes. At rest and every exercise stage, LV end-systolic and diastolic volume index (LVEDVI and LVESVI), SV index (SVI), cardiac index (CI), LV ejection fraction (LVEF), and early lateral mitral flow velocity (Ea) were evaluated. Heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) were continuously recorded. Nonathletes showed a slow increase in CI, and SVI reached a plateau value at a HR of 90beats per minute (bpm). In contrast, CI and SVI increased progressively and continuously in athletes. Both CI and SVI were significantly higher in athletes than in nonathletes at HRs of 100, 110, and 120bpm. LVEDVI kept increasing in athletes while it plateaued in nonathletes. In contrast, LVESV decreased continuously during exercise in both groups. There was no significant difference in LVEF, Ea, SBP, or DBP at rest and during exercise between the two groups. LV responses to exercise in athletes were different from those of in nonathletes; thus, habitual physical training may play an important role in the increase in both SVI and CI in young individuals.

Sex differences in heart rate responses to sub-maximal exercise in young adults

There is paucity of scientific information on sex differences in heart rate (HR) responses during and after a sub-maximal exercise test in young adults. We assessed sex differences in normal HR responses during and after a sub-maximal-effort cycle ergometer exercise test in apparently healthy young adults. One hundred young adults (50 males and 50 females) participated in the study. Subjects performed a sub-maximal exercise at an intensity that produced 60–85% of a pre-determined age-predicted maximum HR. Measurements of subjects’ HR were done at rest, during exercise and post exercise recovery periods. The present data indicated that after adjusting for covariates, greater (P&lt;0.05) HR responses (delta HR 2 min, delta HR 5 min, delta peak HR) were observed in men relative to women. Males also indicated significantly higher (P&lt;0.05) %HRmax and %HRreserve compared to females. Variables of HR response during post-exercise recovery did not differ between males and females. HR responses during exercise were greater in young adult males compared to females while HR responses at post-exercise recovery were similar between the two groups. The present findings may be useful in interpreting more accurately the significance of HR responses during and after exercise in healthy young adults according to sex.

Abstract 19626: Muscle Weakness Induces Left Ventricular Hypertrophy via Frequent Elevation of Functional Arterial Stiffness During Exercise in Patients With Hypertension

Background: Hypertension (HT) characterized by autonomic imbalance, is well known to induce an inappropriate elevation of arterial stiffness resulting in left ventricular hypertrophy (LVH). On the other hand, decreased muscle strength enhances autonomic imbalance by stimulating muscle sympathetic activity during exercise even at low- or moderate-intensity. However, it is unclear whether muscle weakness induces LVH via frequent elevation of functional arterial stiffness during exercise in patients with HT. The aim of this study was to investigate the relationships among muscle strength, autonomic activity during exercise, functional arterial stiffness and LVH in them. Methods: Fifty-five patients with HT aged 68±9 years, 32 males and 23 females, participated in this study. We measured plasma brain natriuretic peptide (BNP) and LV mass index (LVMI) on echocardiogram as parameters of LV overload and LVH, respectively, and knee extension muscle strength. Patients performed a treadmill exercise test to examine heart rate recovery (HRR). We assessed the changes from baseline values of plasma noradrenalin (NA) and brachial-ankle pulse wave velocity (PWV) to those measured just after a cycle ergometer exercise test that was performed at moderate-intensity ([[Unable to Display Character: &amp;#8895;]]NA and [[Unable to Display Character: &amp;#8895;]]PWV, respectively). The HRR, [[Unable to Display Character: &amp;#8895;]]NA and [[Unable to Display Character: &amp;#8895;]]PWV were used as parameters of parasympathetic and sympathetic activities and functional arterial stiffness, respectively. We analyzed the relationships among muscle strength, HRR, [[Unable to Display Character: &amp;#8895;]]NA, [[Unable to Display Character: &amp;#8895;]]PWV, BNP and LVMI. Results: Muscle strength was negatively correlated with [[Unable to Display Character: &amp;#8895;]]NA (r=-0.23, P&lt;0.05), [[Unable to Display Character: &amp;#8895;]]PWV (r=-0.24, P&lt;0.05), BNP (r=-0.23, P&lt;0.05) and LVMI (r=-0.23, P&lt;0.05). No significant relationship was observed between muscle strength and HRR. LVMI was positively correlated with [[Unable to Display Character: &amp;#8895;]]PWV (r=0.28, P&lt;0.05). Conclusion: Muscle weakness induced LVH via frequent elevation of functional arterial stiffness caused by autonomic imbalance during exercise in patients with HT.

A Gaussian Model-Based Probabilistic Approach for Pulse Transit Time Estimation.

In this paper, we propose a new probabilistic approach to pulse transit time (PTT) estimation using a Gaussian distribution model. It is motivated basically by the hypothesis that PTTs normalized by RR intervals follow the Gaussian distribution. To verify the hypothesis, we demonstrate the effects of arterial compliance on the normalized PTTs using the Moens-Korteweg equation. Furthermore, we observe a Gaussian distribution of the normalized PTTs on real data. In order to estimate the PTT using the hypothesis, we first assumed that R-waves in the electrocardiogram (ECG) can be correctly identified. The R-waves limit searching ranges to detect pulse peaks in the photoplethysmogram (PPG) and to synchronize the results with cardiac beats--i.e., the peaks of the PPG are extracted within the corresponding RR interval of the ECG as pulse peak candidates. Their probabilities of being the actual pulse peak are then calculated using a Gaussian probability function. The parameters of the Gaussian function are automatically updated when a new pulse peak is identified. This update makes the probability function adaptive to variations of cardiac cycles. Finally, the pulse peak is identified as the candidate with the highest probability. The proposed approach is tested on a database where ECG and PPG waveforms are collected simultaneously during the submaximal bicycle ergometer exercise test. The results are promising, suggesting that the method provides a simple but more accurate PTT estimation in real applications.

Cardiorespiratory fitness, respiratory function and hemodynamic responses to maximal cycle ergometer exercise test in girls and boys aged 9–11 years: the PANIC Study

We aimed to provide comprehensive data on and reference values for cardiorespiratory fitness, respiratory function and hemodynamic responses during and after maximal cycle ergometer test in children. The participants were a population sample of 140 children (69 girls) aged 9-11 years. Heart rate (HR) and systolic blood pressure (SBP) were measured from pre-exercise rest to the end of recovery. Respiratory gases were measured directly by the breath-by-breath method. Peak workload, HR changes, peak oxygen uptake (VO2), peak oxygen pulse (O2 pulse), peak respiratory exchange ratio (RER) and the lowest ratio of ventilation and carbon dioxide output (VE/VCO2) during the exercise test in girls and boys were presented according to their distributions in 5 categories. HR decreased more during 4-min recovery in boys than in girls (76 vs. 67 beats/min, p < 0.001), whereas SBP decrease was similar in boys and girls (30 vs. 22 mmHg, p = 0.66). Boys had a higher peak VO2 per weight [51.9 vs. 47.6 ml/kg/min, p < 0.001] and per lean mass [67.3 vs. 63.0 ml/kg/min, p < 0.001] than girls. Peak O2 pulse per lean mass was higher in boys than in girls (0.34 vs. 0.31 ml/kg/beat, p < 0.001). There was no difference in the lowest VE/VCO2 during the test between boys and girls (28 vs. 29, p = 0.18). The indicators of cardiorespiratory fitness were better in boys than in girls. These data enable the evaluation of cardiorespiratory function during and after maximal exercise test and the detection of children with abnormal values.

Effects of an 8-weeks erythropoietin treatment on mitochondrial and whole body fat oxidation capacity during exercise in healthy males

The present investigation was performed to elucidate if the non-erythropoietic ergogenic effect of a recombinant erythropoietin treatment results in an impact on skeletal muscle mitochondrial and whole body fatty acid oxidation capacity during exercise, myoglobin concentration and angiogenesis. Recombinant erythropoietin was administered by subcutaneous injections (5000 IU) in six healthy male volunteers (aged 21 ± 2 years; fat mass 18.5 ± 2.3%) over 8 weeks. The participants performed two graded cycle ergometer exercise tests before and after the intervention where VO2max and maximal fat oxidation were measured. Biopsies of the vastus lateralis muscle were obtained before and after the intervention. Recombinant erythropoietin treatment increased mitochondrial O2 flux during ADP stimulated state 3 respiration in the presence of complex I and II substrates (malate, glutamate, pyruvate, succinate) with additional electron input from β-oxidation (octanoylcarnitine) (from 60 ± 13 to 87 ± 24 pmol · s−1 · mg−1 P < 0.01). β-hydroxy-acyl-CoA-dehydrogenase activity was higher after treatment (P < 0.05), whereas citrate synthase activity also tended to increase (P = 0.06). Total myoglobin increased by 16.5% (P < 0.05). Capillaries per muscle area tended to increase (P = 0.07), whereas capillaries per fibre as well as the total expression of vascular endothelial growth factor remained unchanged. Whole body maximal fat oxidation was not increased after treatment. Eight weeks of recombinant erythropoietin treatment increases mitochondrial fatty acid oxidation capacity and myoglobin concentration without any effect on whole body maximal fat oxidation.

Exercise testing and training in people with Huntington’s disease

Objective: To explore exercise response in people with Huntington’s disease (HD). Design: Experimental observational study with a randomly allocated subgroup before/after interventional study. Setting: Community. Subjects: People with HD (n=30) and a healthy comparator group (n=20). Thirteen people from the HD group were randomly allocated to an exercise training program. Main measures: Heart rate (HR) and perceived exertion on the Borg-CR10 scale (RPE) during a submaximal cycle ergometer exercise test (three minute unloaded and nine minute 65%-75%HRmaximum phase). Expired air and lactate measures were available for 8 people with HD during the exercise. Intervention: A 12 week gym and home walking exercise programme (n=13). Results: People with HD achieved a lower work rate at nine minutes (82±42(0-195) v 107±35(50 -185) Watts (p<0.05)), but higher RPE at both three (3±2(0-7) v 1±1(0-4)) and nine minutes (7±3(1-10) v 5± 2(2-9)) both p<0.01, compared to the healthy group and did not achieve a steady state HR during unloaded cycling. People with HD also demonstrated higher than expected lactate at three 2.5±2.5(1.1-8)mmo.L-1 and nine 3.8±1.9(1.2-6.6)mmo.L-1 minutes and respiratory exchange ratio at three 0.78±0.03 (0.74-0.81) and nine minutes 0.94±0.11(0.81-1.15). After exercise training there were no changes observed in HR or RPE responses during the exercise test. Conclusions: There was a large variability in the observed metabolic and physiological responses to exercise in people with HD. The observed exercise responses suggest that altered exercise prescription parameters may be required for people with HD and that exercise response and factors’ affecting this requires further investigation.

Oxygen Cost of Recreational Horse-Riding in Females.

The purpose of this study was to characterize the physiological demands of a riding session comprising different types of recreational horse riding in females. Sixteen female recreational riders (aged 17 to 54 years) completed an incremental cycle ergometer exercise test to determine peak oxygen consumption (VO₂peak) and a 45-minute riding session based upon a British Horse Society Stage 2 riding lesson (including walking, trotting, cantering and work without stirrups). Oxygen consumption (VO₂), from which metabolic equivalent (MET) and energy expenditure values were derived, was measured throughout. The mean VO₂ requirement for trotting/cantering (18.4 ± 5.1 ml·kg⁻¹·min⁻¹; 52 ± 12% VO₂peak; 5.3 ± 1.1 METs) was similar to walking/trotting (17.4 ± 5.1 ml·kg⁻¹·min⁻¹; 48 ± 13% VO₂peak; 5.0 ± 1.5 METs) and significantly higher than for work without stirrups (14.2 ± 2.9 ml·kg⁻¹·min⁻¹; 41 ± 12% VO₂peak; 4.2 ± 0.8 METs) (P = .001). The oxygen cost of different activities typically performed in a recreational horse riding session meets the criteria for moderate intensity exercise (3-6 METs) in females, and trotting combined with cantering imposes the highest metabolic demand. Regular riding could contribute to the achievement of the public health recommendations for physical activity in this population.

Prediction of VO2 peak using OMNI Ratings of Perceived Exertion from a submaximal cycle exercise test.

The primary aim of this study was to develop statistical models to predict peak oxygen consumption (VO2 peak) using OMNI Ratings of Perceived Exertion measured during submaximal cycle ergometry. Male (M = 20.9 yr., SE = 0.4) and female (M = 21.6 yr., SE = 0.5) participants (N = 81) completed a load-incremented maximal cycle ergometer exercise test. Simultaneous multiple linear regression was used to develop separate VO2 peak statistical models using submaximal ratings of perceived exertion for the overall body, legs, and chest/breathing as predictor variables. VO2 peak (L·min(-1)) predicted for men and women from ratings of perceived exertion for the overall body (3.02 ± 0.06; 2.03 ± 0.04), legs (3.02 ± 0.06; 2.04 ± 0.04), and chest/breathing (3.02 ± 0.05; 2.03 ± 0.03) were similar to measured VO2 peak (3.02 ± 0.10; 2.03 ± 0.06, ps > .05). Statistical models based on submaximal OMNI Ratings of Perceived Exertion provide an easily administered and accurate method to predict VO2 peak.

Associations of cardiorespiratory fitness with cardiovascular disease risk factors in middle-aged Chinese women: a cross-sectional study.

BackgroundHigh levels of physical activity (PA) and cardiorespiratory fitness (CRF) are each associated with a favorable cardiovascular disease (CVD) risk profile. However, the relationship between CRF and obesity is still inconsistent across studies, and there has been no thorough exploration of the independent contribution of CRF to different CVD risk factors in Chinese women. This study investigated the relationship between CRF and CVD risk factors in 40–49 year old women in Beijing.MethodsThe study included 231 urban-dwelling asymptomatic 40–49 year old women. Body mass index (BMI), body fat percentage (BF%), blood glucose, blood lipids, blood pressure, and pulse wave velocity (PWV) were measured at rest. Cycle ergometer exercise tests were conducted to assess CRF as indicated by maximal oxygen uptake (VO2max). Participants were categorized into three CRF levels (low, moderate and high).ResultsHigh CRF level was associated with significantly less BF%, lower PWV, and higher weekly physical activity compared with low and moderate CRF (P < 0.05). Compared to high CRF, the odds ratios for having ≥3 main CVD risk factors (overweight, hypertension, and dyslipidemia) in low and moderate CRF were 2.09 (95% CI: 1.48-2.94) and 1.84 (95% CI: 1.29-2.62), respectively. The proportion of participants with clinical ST segment depression and prolonged QTC interval during cycle ergometer testing was significantly higher in women with low CRF.ConclusionsOverall, Chinese middle-aged women demonstrated a moderate level of CRF. CRF was independently associated with CVD risk factors, including overweight, hypertension, dyslipidemia, arterial stiffness, and abnormal ECG during exercise, with the least fit women exhibiting the highest number of CVD risk factors.

Association of different risk factors with exercise and resting blood pressure in 532 subjects aged 12-17 years

High blood pressure (BP) values in adolescents are caused by a variety of risk factors. In this group, the reproducibility of resting office BP is poor due to emotional and situational factors. With adults, it is the case that exercise BP is more closely associated with cardiovascular prognosis. However, it is unclear whether exercise BP in children and adolescents has a higher prognostic relevance than resting BP. In the present study, the association of resting vs. exercise BP values with classic risk factors was compared in order to evaluate the importance of BP during exercise. In the Kiel EX.PRESS. (EXercise and PRESSure) study, resting and exercise BP of 532 young subjects (aged 12-17 years) was determined. Systolic exercise BP was measured at 1.5 Watt / kg body weight using a standardized cycle ergometer exercise test. Age, height, body weight and waist circumference of all participants were collected. The physical working capacity at heart rate of 170/min (PWC 170) was used as a fitness parameter. The volume of moderate-to-vigorous physical activity (MVPAindex) and screen time (h / day) were determined using questionnaires. In addition, family history of hypertension, parental smoking and educational level were included in the study. The association of resting vs. exercise BP values with these variables was calculated and compared. After adjustment for age, sex and height, there were significant correlations of both resting and exercise BP with BMI (r1⁄40.289 vs. r1⁄40.312, p 2h / day, fit vs. unfit, high ( 5 days / week) vs. low (< 5 days / week) MVPA, non-smoking vs. smoking parents, active vs. inactive parents and high vs. low educational level, mean systolic exercise BP was significantly higher in the latter variable, respectively. However, no significant difference was found concerning resting BP. Group differences for mean systolic exercise BP values were between 3.7 and 5.2 mmHg. In contrast, groups with high vs. normal BMI or waist circumference and positive vs. negative family history of hypertension had higher exercise and resting BP values. In conclusion, exercise BP in this group of 12-17 year-old subjects was closely related to a variety of classic risk factors mainly concerning fitnessand activity-related parameters. In addition, a number of other lifestyleand family-related parameters demonstrated a correlation with exercise BP at least as closely as with resting BP. Our data support the importance of exercise BP in young subjects. Thus, the determination of BP during exercise in clinical practice might be of prognostic significance not only in adults.

Breathing heliox reduces expiratory flow limitation and improves exercise performance in adult survivors of extreme preterm birth (882.4)

Extreme preterm birth (&lt;32 weeks gestational age) results in arrested development of the lung characterized by abnormal alveologenesis and pulmonary vasculogenesis causing obstructive lung disease that persists into adulthood. We have recently shown that adults with a history of extreme preterm birth (PRE) have reduced aerobic exercise capacity relative to full term controls (CONT) that is not explained by pulmonary gas exchange inefficiency during exercise. These PRE subjects also have significant exercise‐induced flow limitation (EIFL), which has been suggested to be associated with a reduction in exercise capacity in healthy humans and in COPD subjects. Therefore, we hypothesized that reducing EIFL by breathing heliox (21% O2, 79% He) would improve exercise performance. Both PRE (n = 4) and CONT (n = 4) subjects performed two cycle ergometer exercise tests to exhaustion at 80% of their maximum power output; one breathing room air and one breathing heliox. Measurements breathing heliox were compared to those breathing room air at iso‐time. Flow‐volume loops were measured at rest and during both exercise tests to quantify EIFL. EIFL significantly decreased in PRE from room air (57% of tidal volume; VT) to heliox (9% VT), while CONT did not exhibit EIFL in either condition. Time to exhaustion significantly increased in PRE (38%), but not CONT (9%), breathing heliox compared to room air. These data suggest that excessive EIFL, may lead to an excessive work of breathing and/or mechanical constraints to increasing tidal volume during exercise, thereby significantly limiting exercise performance in PRE subjects.Grant Funding Source: Supported by AHA Scientist Development Grant and OHSU Early Clinical Investigator Grant

Higher cardiorespiratory fitness attenuates the risk of atherosclerosis associated with ADRB3 Trp64Arg polymorphism

β3-Adrenergic receptor (ADRB3) Trp64Arg polymorphism is associated with atherogenic risk factors that include weight gain, insulin resistance, and diabetes. Habitual exercise brings higher cardiorespiratory fitness and results in the amelioration of atherosclerotic risk factors. However, the effects of cardiorespiratory fitness level and ADRB3 Trp64Arg polymorphism on the risk of cardiovascular disease remain unclear. A cross-sectional investigation of 877 Japanese men and women (18-75 years old) was performed to clarify the effects of cardiorespiratory fitness on the relationship between ADRB3 Trp64Arg polymorphism and risk of cardiovascular disease. Common carotid intima-media thickness (ccIMT) and blood lipid profiles were assessed as surrogate markers of atherosclerosis. We measured peak oxygen uptake (V̇O(2peak)) during incremental cycle ergometer exercise testing. Subjects were divided into groups with high (High-Fit) and low (Low-Fit) levels of cardiorespiratory fitness based on the median value of V̇O(2peak) for sex and decade. Levels of body fat, triglycerides, and plasma glucose were lower and high-density lipoprotein cholesterol levels and V̇O(2peak) were higher in High-Fit subjects than Low-Fit subjects. ADRB3 Trp64Arg polymorphism did not significantly affect ccIMT or blood lipid profiles. In Low-Fit subjects, ccIMT was higher in individuals with the Arg/Arg genotype compared to the Trp/Trp and Trp/Arg genotypes (each P < 0.0001); however, ADRB3 polymorphism had no effect in High-Fit subjects. Higher levels of cardiorespiratory fitness may attenuate the risk of atherosclerosis associated with ADRB3 Trp64Arg polymorphism.

DIFFERENTIAL DIAGNOSIS OF HYPERTROPHIC CARDIOMYOPATHY AND HYPERTENSIVE HEART DISEASE BY EXERCISE TESTING

Aim. To assess the effectiveness of a bicycle ergometer exercise test in differentiation of hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD). Material and methods. 42 patients with HCM (mean age 49,8±15,3-28 male) and 25 patients with HHD (mean age 47,0±12,4-16 male) were studied. All patients underwent upright bicycle ergometer exercise test after withdrawal of drug therapy. Results. It is well-known that abnormal blood pressure response (ABPR) and ST depression with angina during exercise are the criteria for the termination of test (RTT) and are the HCM attributes (after ruling out the coronary atherosclerosis by coronarography). With the use of nonparametric statistics we found significant difference between HCM and HHD in systolic blood pressure (SBP) at the end of the test (174,6±30,8 and 210,4±21,1 mmHg; p=0,000006), time recovery after test (TR) (10,0±4,0 and 7,1±1,6 min; p=0,007), breathlessness as a RTT (38,4% and 4%, p=0,022); extrasystole as a RTT (12,5% and 0%). With the use of logistic regression we found a dependency for differential diagnosis of HCM and HHD: Diagnosis = 0,41*SBPe-40,79-3,65*TR-13,34*BR-41,87*EXT-1000*0 TH . Where SBPe is SBP at the end of the test; TR equals 1 if breathlessness was the RTT and 0 otherwise; EXT equals 1 if extrasystole was the RTT and 0 otherwise; OTH equals 1 if ABPR, ST depression or stenocardia were the RTT and 0 otherwise. Diagnosis is greater than 0 for HHD and less than 0 for HCM patients. For all patients included in our study the dependency provides correct result. Conclusion. The exercise testing gives useful information and can be applied for differential diagnosis of HCM and HDD.

Cardiovascular fitness and haemodynamic responses to maximal cycle ergometer exercise test in children 6–8 years of age

We investigated cardiovascular fitness and haemodynamic responses to maximal cycle ergometer exercise test in children. The participants were a population sample of 425 children (204 girls, 221 boys) aged 6–8 years. Heart rate (HR) and systolic blood pressure (SBP) were measured from the beginning of pre-exercise rest to the end of recovery period. We provided reference values for peak workload and changes in HR and SBP during and after maximal exercise test in girls and boys. Girls had a lower cardiovascular fitness, indicated by peak workload per body weight [mean (2 s) 2.7 (0.9) vs. 3.1 (1.0) W · kg–1, P < 0.001] and lean mass [mean (2 s) 3.5 (0.9) vs. 3.8 (1.0) W· kg–1, P < 0.001] than boys. Plateau or decline in SBP close to the end of the test was found in about third of children and was considered a normal SBP response. Girls had a slower HR decrease within 2 min after the test than boys [mean (2 s) 53 (18) vs. 59 (22) beats · min–1, P < 0.001]. The results are useful for physicians and exercise physiologists to evaluate cardiovascular fitness and haemodynamic responses to exercise in children and to detect children with low exercise tolerance or abnormal haemodynamic responses to exercise.