Category Archives: Publications

Physical activity and cardiorespiratory fitness – a ten year follow-up.

Bahls M; Ittermann T; Ewert R; Stubbe B; Völzke H; Friedrich N; Felix SB; Dörr M;

Scandinavian journal of medicine & science in sports [Scand J Med Sci Sports] 2020 Nov 18. Date of Electronic Publication: 2020 Nov 18.

Physical activity (PA) may influence cardio-respiratory fitness (CRF). Yet, PA takes place in different domains (i.e. sports related physical activity [SPA], leisure time related physical activity [LTPA] and work-related physical activity [WPA]) and not all domain-specific PA may help to maintain high CRF levels throughout life. We assessed the relationship between changes in domain specific PA and the age-related decline in CRF. We analyzed data of 353 men (median age 50 years; inter-quartile range [IQR] 40 to 60) and 335 women (median age 50 years; IQR 41 to 59) with data for domain-specific PA as well as CRF testing measured ten years apart. CRF was assessed with cardiorespiratory exercise testing. Domain specific PA was measured using the Baecke questionnaire. During the 10 year follow-up CRF decreased in men from 29.3 (IQR 25.0 to 34.7) ml/min/kg to 24.3 (IQR 20.8 to 27.3) ml/min/kg. In women CRF declined from 26.0 (IQR 21.0 to 30.9) to 21.4 (IQR 18.3 to 25.6) ml/min/kg. A one point higher SPA at baseline was related to a 1.14 (95% confidence interval [CI] -1.50 to -0.53) ml/min/kg greater decrease in VO 2peak . A one point greater SPA and LTPA over time was associated with a 1.68 (95% CI 1.06 to 2.29) ml/min/kg and 1.24 (95% CI 0.57 to 1.90) ml/min/kg lower decrease in VO 2peak , respectively. Neither baseline values nor changes of WPA were associated with CRF. Sports and leisure time related PA may attenuate the age related decline in CRF.

Central Command and the Regulation of Exercise Heart Rate Response in Heart Failure with Preserved Ejection Fraction.

Sarma S; Howden E; Lawley J; Samels M; Levine BD;

Circulation [Circulation] 2020 Nov 18. Date of Electronic Publication: 2020 Nov 18.

Background: Chronotropic incompetence (CI) is common in HFpEF and is linked to impaired aerobic capacity. Whether upstream autonomic signaling pathways responsible for raising exercise heart rate (HR) are impaired in HFpEF is unknown. We investigated the integrity of central command and muscle metaboreceptor function, two predominant mechanisms responsible for exertional increases in HR, in HFpEF and senior control subjects. Methods: Fourteen healthy, senior controls (7M,7F) and 20 carefully screened HFpEF patients (8M,12F) underwent cardiopulmonary exercise testing (peak VO 2 ) and static handgrip exercise at 40% of maximal voluntary contraction (MVC) to fatigue with post-exercise circulatory arrest (PECA) for 2 minutes to assess central command and metaboreceptor function respectively.
Results: Peak VO 2 (13.1 ± 3.4 vs 22.7 ± 4.0 ml/kg/min; p<0.001) and HR (122 ± 20 vs 155 ± 14 bpm; p<0.001) were lower in HFpEF than senior controls. There were no significant differences in peak HR response during static handgrip between groups (HFpEF vs controls: 90 ± 13 vs 93 ± 10 bpm; p=0.49). Metaboreceptor function defined as mean arterial blood pressure at the end of PECA was also not significantly different between groups.
Conclusions: Central command (vagally mediated) and metaboreceptor function (sympathetically mediated) in patients with HFpEF were not different from healthy senior controls despite significantly lower peak whole-body exercise heart rates. These results demonstrate key reflex autonomic pathways regulating exercise heart rate responsiveness are intact in HFpEF.

Impact of peak respiratory exchange ratio on the prognostic power of symptoms-limited exercise testing using Bruce protocol in patients with Fontan physiology.

Niu J; Godoy A; Kadish T; Das BB;

Cardiology in the young [Cardiol Young] 2020 Nov 19, pp. 1-8. Date of Electronic Publication: 2020 Nov 19.

Objectives: We evaluated the impact of peak respiratory exchange ratio on the prognostic values of cardiopulmonary exercise variables during symptoms-limited incremental exercise tests in patients with Fontan physiology.
Methods: Retrospective single-centre chart review study of Fontan patients who underwent exercise testing using the Bruce protocol between 2014 and 2018 and follow-up.
Results: A total of 34 patients (age > 18 years) had a Borg score of ≥7 on the Borg 10-point scale, but only 50% of patients achieved a peak respiratory exchange ratio of ≥ 1.10 (maximal test). Peak oxygen consumption, percent-predicted peak oxygen consumption, and peak oxygen consumption at the ventilatory threshold was reduced significantly in patients with a peak respiratory exchange ratio of < 1.10. Peak oxygen consumption and percent-predicted peak oxygen consumption was positively correlated with peak respiratory exchange ratio values (r = 0.356, p = 0.039). After a median follow-up of 21 months, cardiac-related events occurred in 16 (47%) patients, with no proportional differences in patients due to their respiratory exchange ratio (odds ratio, 0.62; 95% CI: 0.18-2.58; p = 0.492). Multivariate Cox proportional hazard analysis showed percent-predicted peak oxygen consumption, peak heart rate, and the oxygen uptake efficient slope were highly related to the occurrence of events in patients only with a peak respiratory exchange ratio of ≥ 1.10.
Conclusions: The value of peak cardiopulmonary exercise variables is limited for the determination of prognosis and assessment of interventions in Fontan patients with sub-maximal effort. Our findings deserve further research and clinical application.

Longitudinal changes in exercise capacity among adult cystic fibrosis patients.

Boutou AK; Manika K; Hajimitrova M; Pitsiou G; Giannakopoulou P; Sourla E; Kioumis I;

Advances in respiratory medicine [Adv Respir Med] 2020; Vol. 88 (5), pp. 420-423.

Introduction: Longitudinal data regarding changes in exercise capacity among adult cystic fibrosis (CF) patients are currently scarce. The aim of this brief report was to assess changes in exercise capacity among adult CF patients with stable and mild-to-moderate disease eight years after their initial evaluation.
Material and Methods: Maximum cardiopulmonary exercise testing (CPET) was utilized. Other assessments included Doppler echocardiography, the 6-minute walking test, spirometry, and lung volume evaluation.
Results: Eleven (6 male, 5 female) patients completed both evaluations (initial and after eight years). During follow-up, indices of ventilatory impairment (such as ventilatory reserve; p=0.019, and ventilatory equivalent for carbon dioxide; p = 0.047) deterio-rated significantly following a decline in respiratory function measurements. Peak oxygen uptake (VO2), both as an absolute (26.6 ± 8.46 vs 23.89 ± 6.16 mL/kg/min; p = 0.098) and as a % of predicted value (71.21 ± 16.54 vs 70.60 ± 15.45; p = 0.872), did not deteriorate. This is also true for oxygen pulse (p = 0.743), left heart ejection fraction (p = 0.574), and pulmonary artery systolic pressure (p = 0.441). However, the anaerobic threshold, both as an absolute (p = 0.009) and as a % of predicted value (p = 0.047), was significantly lower during follow-up.
Conclusion: In adult CF patients with stable, mild-to-moderate disease, a peak VO2 may be preserved for several years. However, even in these patients, deconditioning is present.

Prediction Equations for Maximal Aerobic Capacity on Cycle Ergometer for the Spanish Adult Population.

Puente-Maestú L; Ortega F; Pedro JG; Rodríguez-Nieto MJ; Gómez-Seco J; Gáldiz B; Ojanguren I; Muñoz X; Blanco I; Burgos F; Rodríguez-Chiaradía DA; Gea J; García-Rio F;

Archivos de bronconeumologia [Arch Bronconeumol] 2020 Oct 10. Date of Electronic Publication: 2020 Oct 10.

Background: Frequently used reference values for clinical exercise testing have been derived from non-random samples and some with poorly defined maximal criteria. Our objective was to obtain population based reference values for peak oxygen uptake (V˙O 2 ) and work rate (WR) for cardiopulmonary exercise testing in a representative sample of Caucasian Spanish men and women.
Methods: 182 men and women, 20-85 years old, were included and exercised on cycle-ergometer to exhaustion. (V˙O 2 ) and WR were measured. The equations obtained from this sample were validated in an independent cohort of 69 individuals, randomly sampled form the same population. Then a final equation merging the two cohorts (=251) was produced.
Results: Height, sex and age resulted predictive of both V˙O 2 peak and WR. Weight and physical activity added very little to the accuracy to the equations. The formulas V˙O 2 peak=0.017⋅height(cm)-0.023⋅age(years)+0.864⋅sex(female=0/male=1)±179lmin -1 , and peak WR=1.345 · height (cm) – 2.074 · age (years)+76.54 · sex (female=0/male=1)±21.2W were the best compromise between accuracy and parsimony.
Conclusions: This study provides new and accurate V˙O 2 peak and WR rate reference values for individuals of European Spanish descent.

Elevated exercise ventilation in mild COPD is not linked to enhanced central chemosensitivity.

Phillips DB; Domnik NJ; Elbehairy AF; Preston ME; Milne KM; James MD; Vincent SG; Ibrahim-Masthan M; Neder JA; O’Donnell DE;

Respiratory physiology & neurobiology [Respir Physiol Neurobiol] 2020 Nov 05, pp. 103571. Date of Electronic Publication: 2020 Nov 05.

Background: The purpose of this study was to determine if altered central chemoreceptor characteristics contributed to the elevated ventilation relative to carbon dioxide production (V̇ E /V̇CO 2 ) response during exercise in mild chronic obstructive pulmonary disease (COPD).
Methods: Twenty-nine mild COPD and 19 healthy age-matched control participants undertook lung function testing followed by symptom-limited incremental cardiopulmonary exercise testing (CPET). On a separate day, basal (non-chemoreflex) ventilation (V̇ EB ), the central chemoreflex ventilatory recruitment threshold for CO 2 (VRTCO 2 ), and central chemoreflex sensitivity (V̇ ES ) were assessed using the modified Duffin’s CO 2 rebreathing method. Resting arterialized blood gas data were also obtained.
Results: At standardized exercise intensities, absolute V̇ E and V̇ E /V̇CO 2 were consistently elevated and the end-tidal partial pressure of CO 2 was relatively decreased in mild COPD versus controls (all p < 0.05). There were no between-group differences in resting arterialized blood gas parameters, basal V̇ E , VRTCO 2 , or V̇ ES (all p > 0.05).
Conclusion: These data have established that excessive exercise ventilation in mild COPD is not explained by altered central chemosensitivity.

Using heart rate to estimate the minute ventilation and inhaled load of air pollutants.

Guo Q; Zhao Y; Shao J; Cao S; Wang Q; Wu W;

The Science of the total environment [Sci Total Environ] 2020 Oct 19, pp. 143011. Date of Electronic Publication: 2020 Oct 19.

Background: The health effects of air pollution are associated with the concentration of pollutants and ventilation (VE). VE is difficult to measure directly and has been predicted by heart rate (HR). However, it is unclear whether equations between HR and VE obtained from a laboratory cardiopulmonary exercise test (CPET) can be extended to external groups and there is still a gap in their relationship for a Chinese population.
Objective: To establish an association between HR and VE in young Chinese individuals and verify the external validity of the model.
Methods: Eighty non-smoking participants aged 16-21 years underwent incremental tests using a bicycle ergometer, where the HR and minute VE were measured simultaneously. Linear mixed models were constructed with data obtained from a CPET. Ten individuals were chosen randomly as the external validation group. The predictive performance was assessed using an eight-fold cross-validation procedure. Air pollution concentration was monitored during the CPET and the inhaled load was calculated.
Results: The overall estimation of the intercept and slope for all participants was 0.585 ± 0.013 and 0.007 ± 0.00002, respectively. The overall fitted R squared (R 2 ) was 0.84. The median difference between the measured VE and the predicted VE was 0.3 L/min, and the difference between the inhaled load based on the fitted VE and the measured VE was 0.0-0.3 μg across all the participants. The eight folds cross-validation R 2 value was 0.78, suggesting high predictive accuracy.
Conclusion: This is the first study to derive a novel equation for the relationship between HR and VE in a young Chinese population and verify its external validity. This will be important in the assessment of the inhaled load in future epidemiology studies. However, inter-individual variations should also be considered when VE is estimated at an individual level.

Multidimensional breathlessness assessment during cardiopulmonary exercise testing in healthy adults.

Lewthwaite H; Jensen D;

European journal of applied physiology [Eur J Appl Physiol] 2020 Nov 03. Date of Electronic Publication: 2020 Nov 03.

Purpose: This study explored if healthy adults could discriminate between different breathlessness dimensions when rated immediately one after another (successively) during symptom-limited incremental cardiopulmonary cycle exercise testing (CPET) using multiple single-item rating scales.
Methods: Fifteen apparently healthy adults (60% male) aged 22 ± 2 years performed six incremental cycle CPETs separated by ≥ 48 h. During each CPET (at rest, every 2-min and at end exercise), participants rated different breathlessness sensations using the 0-10 modified Borg scale using one of six assessment protocols, randomized for order: (1) ‘BREATHLESS ALL ‘ = breathlessness sensory intensity (SI), breathlessness unpleasantness (UN), work/effort of breathing (SQ W/E ), and unsatisfied inspiration (SQ UI ) assessed; (2) SI and UN assessed; and (3-6) SI, UN, SQ W/E , and SQ UI each assessed alone. Physiological responses to CPET were also evaluated.
Results: Physiological and breathlessness responses to CPET were comparable across the six protocols, with the exception of SI rated lower at the highest submaximal power output (220 ± 56 watts) during the BREATHLESS ALL protocol (0-10 Borg units 4.2 ± 1.7) compared to SI + UN (5.2 ± 2.1, p = 0.03) and SI alone (5.1 ± 1.9, p = 0.04) protocols. Ratings of SI and SQ W/E were not significantly different when assessed in the same protocol, and were significantly higher than UN and SQ UI , which were comparable.
Conclusion: In healthy younger adults, use of two separate single-item rating scales to assess breathlessness during CPET is feasible and enables the distinct sensory intensity and affective dimensions of exertional breathlessness to be assessed.

Impact of exercise training and supplemental oxygen on submaximal exercise performance in patients with COPD.

Neunhäuserer D; Reich B; Mayr B; Kaiser B; Lamprecht B; Ermolao A; Studnicka M; Niebauer J;

Scandinavian journal of medicine & science in sports [Scand J Med Sci Sports] 2020 Nov 05. Date of Electronic Publication: 2020 Nov 05.

Functional impairment caused by chronic obstructive pulmonary disease (COPD) impacts on activities of daily living and quality of life. Indeed, patients’ submaximal exercise capacity is of crucial importance. It was the aim of this study to investigate the effects of an exercise training intervention with and without supplemental oxygen on submaximal exercise performance. This is a secondary analysis of a randomized, controlled, double-blind, crossover trial. 29 COPD patients (63.5±5.9 years; FEV 1 46.4±8.6%) completed two consecutive 6-week periods of high intensity interval cycling and strength training, which was performed three times/week with either supplemental oxygen or medical air (10 L/min). Submaximal exercise capacity as well as the cardiocirculatory, ventilatory and metabolic response were evaluated at isotime (point of termination in the shortest cardiopulmonary exercise test), at physical work capacity at 110 bpm of heart rate (PWC 110), at the anaerobic threshold (AT), and at the lactate-2 mmol/L threshold. After 12 weeks of exercise training, patients improved in exercise tolerance, shown by decreased cardiocirculatory (heart rate, blood pressure) and metabolic (respiratory exchange ratio, lactate) effort at isotime; ventilatory response was not affected. Submaximal exercise capacity was improved at PWC 110, AT and the lactate-2 mmol/L threshold, respectively. Although supplemental oxygen seems to affect patients’ work rate at AT and the lactate-2 mmol/L threshold, no other significant effects were found. The improved submaximal exercise capacity and tolerance might counteract patients’ functional impairment. Although cardiovascular and metabolic training adaptations were shown, ventilatory efficiency remained essentially unchanged. The impact of supplemental oxygen seems less important on submaximal training effects.

Evaluation of Fontan failure by classifying the severity of Fontan-associated liver disease: a single-centre cross-sectional study

Anastasia Schleiger  Peter Kramer  Madeleine Salzmann  Friederike Danne Stephan Schubert Christian Bassir Tobias Müller Frank Tacke  Hans-Peter Müller Felix Berger   Joachim Photiadis Stanislav Ovroutsk

Objectives: Fontan-associated liver disease (FALD) is a hallmark of the failing Fontan circulation, but no general classification of FALD severity exists. In this study, we propose a scoring system to grade the severity of FALD and analyse its applicability for evaluation of Fontan failure.
Methods: From 2017 to 2019, a total of 129 successive Fontan patients received a comprehensive hepatic assessment. The FALD score was based on results from laboratory testing, hepatic ultrasound and transient elastography by assigning scoring points for each abnormality detected. FALD severity was graded mild, moderate and severe. Haemodynamic assessment was performed using echocardiography, cardiopulmonary exercise testing and catheterization.

Results: FALD was graded absent/ mild, moderate and severe in 53, 26 and 50 patients, respectively. Cardiopulmonary capacity was significantly impaired in patients with severe FALD compared to patients with absent/mild FALD (P = 0.001). The FALD score significantly correlated with pulmonary artery pressure (P = 0.001), end-diastolic ventricular pressure (P < 0.001), hepatic venous pressure (P = 0.004) and wedged hepatic venous pressure (P = 0.009). Fontan failure was present in 21 patients. FALD was graded moderate in 2 and severe in 19 of these patients. The FALD score accurately discriminated patients with and without Fontan failure (sensitivity 90.5%, specificity 71.3%).
Conclusions: The FALD score significantly correlates with impaired Fontan haemodynamics. A cut-off value ≥6.0 has a high diagnostic accuracy in detecting Fontan failure.