Exercise response and the effect of supplemental oxygen during interval training on O2 uptake kinetics, blood lactate levels, and endurance performance in patients with mild, moderate and severe cystic fibrosis

Background: Exercise performance is reduced in individuals with moderate to severe cystic fibrosis (CF). A ventilatory mechanical limitation, arterial hypoxemia, cardiovascular abnormalities, alteration in O2 uptake kinetics and reduced muscle strength may contribute to the reduced exercise performance in individuals with CF patients. The purpose of this research was to compare the exercise response in patients with different CF severities using non- invasive methods, and examine the effect of exercise training with and without O2 supplementation on exercise performance. Methods: Study 1: Adults (n=33) with different severities of CF and healthy controls (n=34) had their body composition, and pulmonary function assessed, and performed a peak exercise test. Study 2: Adults (n=28) with different severities of CF and healthy controls (n=19) had their muscle strength, pulmonary function, body composition and V̇O2peak assessed, and performed a submaximal exercise tests. Study 3: Adults with different severities of CF who were randomly assigned to a placebo (n=6) or O2 supplemental (O2Suppl) (n=5) group undertook interval training on a cycle ergometer 2 days/week for 8 weeks (single blind). Body composition, pulmonary function, V̇O2peak, muscle strength, time to complete a 6 minute walk and performance during a constant work load submaximal tests were assessed before and after the training study. Results: Peak exercise capacity and muscle strength were reduced and O2 uptake kinetics was slower in CF patients than healthy controls. The provision of supplemental O2 during training improved O2 uptake kinetics and resulted in a decrease in ventilation, respiratory rate and blood lactate levels during exercise. Conclusion: Depending on disease severity, the reduction in exercise capacity in CF patients is related to a reduced lean body mass, reduced gas exchange, ventilatory limitation, and an altered cardiovascular response. The provision of supplemental O2 during exercise training may improve endurance capacity in patients with CF

A wearable electrochemical sensor for the real-time measurement of sweat sodium concentration

We report a new method for the real-time quantitative analysis of sodium in human sweat, consolidating sweat collection and analysis in a single, integrated, wearable platform. This temporal data opens up new possibilities in the study of human physiology, broadly applicable from assessing high performance athletes to monitoring Cystic Fibrosis (CF) sufferers. Our compact Sodium Sensor Belt (SSB) consists of a sodium selective Ion Selective Electrode (ISE) integrated into a platform that can be interfaced with the human body during exercise. No skin cleaning regime or sweat storage technology is required as the sweat is continually wicked from the skin to a sensing surface and from there to a storage area via a fabric pump. Our results suggest that after an initial equilibration period, a steady-state sodium plateau concentration was reached. Atomic Absorption Spectroscopy (AAS) was used as a reference method, and this has confirmed the accuracy of the new continuous monitoring approach. The steady-state concentrations observed were found to fall within ranges previously found in the literature, which further validates the approach. Daily calibration repeatability (n 1⁄4 4) was +/- 3.0% RSD and over a three month period reproducibility was +/- 12.1% RSD (n 1⁄4 56). As a further application, we attempted to monitor the sweat of Cystic Fibrosis (CF) sufferers using the same device. We observed high sodium concentrations symptomatic of CF ($60 mM Na+) for two CF patients, with no conclusive results for the remaining patients due to their limited exercising capability, and high viscosity/low volume of sweat produced

A Machine Learning Approach to the Interpretation of Cardiopulmonary Exercise Tests: Development and Validation

Objective. At present, there is no consensus on the best strategy for interpreting the cardiopulmonary exercise test’s (CPET) results. This study is aimed at assessing the potential of using computer-aided algorithms to evaluate CPET data for identifying chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD). Methods. Data from 234 CPET files from the Pulmonary Institute, at Sheba Medical Center, and the Givat-Washington College, both in Israel, were selected for this study. The selected CPET files included patients with confirmed primary CHF (n=73), COPD (n=75), and healthy subjects (n=86). Of the 234 CPETs, 150 (50 in each group) tests were used for the support vector machine (SVM) learning stage, and the remaining 84 tests were used for the model validation. The performance of the SVM interpretive module was assessed by comparing its interpretation output with the conventional clinical diagnosis using distribution analysis. Results. The disease classification results show that the overall predictive power of the proposed interpretive model ranged from 96% to 100%, indicating very high predictive power. Furthermore, the sensitivity, specificity, and overall precision of the proposed interpretive module were 99%, 99%, and 99%, respectively. Conclusions. The proposed new computer-aided CPET interpretive module was found to be highly sensitive and specific in classifying patients with CHF or COPD, or healthy. Comparable modules may well be applied to additional and larger populations (pathologies and exercise limitations), thereby making this tool powerful and clinically applicable

A Wearable Electrochemical Sensor for the Real-Time Measurement of Sweat Sodium Concentration

We report a new method for the real-time quantitative analysis of sodium in human sweat,consolidating sweat collection and analysis in a single, integrated, wearable platform. This temporaldata opens up new possibilities in the study of human physiology, broadly applicable from assessinghigh performance athletes to monitoring Cystic Fibrosis (CF) sufferers. Our compact Sodium Sensor Belt (SSB) consists of a sodium selective Ion Selective Electrode (ISE) integrated into a platform that can be interfaced with the human body during exercise. No skin cleaning regime or sweat storagetechnology is required as the sweat is continually wicked from the skin to a sensing surface and fromthere to a storage area viaa fabric pump. Our results suggest that after an initial equilibration period,a steady-state sodium plateau concentration was reached. Atomic Absorption Spectroscopy (AAS) wasused as a reference method, and this has confirmed the accuracy of the new continuous monitoring approach. The steady-state concentrations observed were found to fall within ranges previously foundin the literature, which further validates the approach

High-intensity interval training accelerates oxygen uptake kinetics and improves exercise tolerance for individuals with cystic fibrosis

Background: Exercise training provides benefits for individuals with cystic fibrosis; however, the optimal program is unclear. High-intensity interval training is safe and effective for improving ‘functional capacity’ in these individuals with peak rate of O2 uptake typically referenced. The ability to adjust submaximal rate of oxygen uptake (V̇O2 kinetics) might be more important for everyday function because maximal efforts are usually not undertaken. Moreover, the ability of high-intensity training to accelerate V̇O2 kinetics for individuals with cystic fibrosis could be enhanced with O2 supplementation during training. Methods: Nine individuals with cystic fibrosis completed incremental cycling to limit of tolerance followed by 8 weeks of high-intensity interval cycling (2 sessions per week x ~ 45 min per session) either with (n = 5; O2+) or without (AMB) oxygen supplementation (100%). Each session involved work intervals at 70% of peak work rate followed by 60s of recovery at 35%. For progression, duration of work intervals was increased according to participant tolerance. Results: Both groups experienced a significant increase in work-interval duration over the course of the intervention (O2+, 1736 ± 141 v. 700 ±154 s; AMB, 1463±598 v. 953±253s; P=0.000); however, the increase experienced by O2+ was greater (P=0.027). During low-intensity constant-work-rate cycling, the V̇O2 mean response time was shortened post compared to pre training (O2+, 34±11 v. 44±9s; AMB, 39±14 v. 45±17s; P= 0.000) while during high-intensity constant-work-rate cycling, time to exhaustion was increased (O2+, 1628 ± 163 v. 705 ±133s; AMB, 1073±633 v. 690±348s; P=0.002) and blood [lactate] response was decreased (O2+, 4.5±0.9 v. 6.3 ± 1.4 mmol. L−1; AMB, 4.5 ±0.6 v. 5.2 ±1.4mmol. L−1; P=0.003). These positive adaptations were similar regardless of gas inspiration during training

High-intensity interval training accelerates oxygen uptake kinetics and improves exercise tolerance for individuals with cystic fibrosis

Background: Exercise training provides benefits for individuals with cystic fibrosis; however, the optimal program is unclear. High-intensity interval training is safe and effective for improving 'functional capacity' in these individuals with peak rate of O2 uptake typically referenced. The ability to adjust submaximal rate of oxygen uptake (V̇O2 kinetics) might be more important for everyday function because maximal efforts are usually not undertaken. Moreover, the ability of high-intensity training to accelerate V̇O2 kinetics for individuals with cystic fibrosis could be enhanced with O2 supplementation during training. Methods: Nine individuals with cystic fibrosis completed incremental cycling to limit of tolerance followed by 8 weeks of high-intensity interval cycling (2 sessions per week x ~ 45 min per session) either with (n = 5; O2+) or without (AMB) oxygen supplementation (100%). Each session involved work intervals at 70% of peak work rate followed by 60 s of recovery at 35%. For progression, duration of work intervals was increased according to participant tolerance. Results: Both groups experienced a significant increase in work-interval duration over the course of the intervention (O2+, 1736 ± 141 v. 700 ± 154 s; AMB, 1463 ± 598 v. 953 ± 253 s; P = 0.000); however, the increase experienced by O2+ was greater (P = 0.027). During low-intensity constant-work-rate cycling, the V̇O2 mean response time was shortened post compared to pre training (O2+, 34 ± 11 v. 44 ± 9 s; AMB, 39 ± 14 v. 45 ± 17 s; P = 0.000) while during high-intensity constant-work-rate cycling, time to exhaustion was increased (O2+, 1628 ± 163 v. 705 ± 133 s; AMB, 1073 ± 633 v. 690 ± 348 s; P = 0.002) and blood [lactate] response was decreased (O2+, 4.5 ± 0.9 v. 6.3 ± 1.4 mmol. L- 1; AMB, 4.5 ± 0.6 v. 5.2 ± 1.4 mmol. L- 1; P = 0.003). These positive adaptations were similar regardless of gas inspiration during training. Conclusion: Eight weeks of high-intensity interval training for patients with cystic fibrosis accelerated V̇O2 kinetics and increased time to exhaustion. This provides some evidence that these patients may benefit from this type of exercise. Trial registration: This study was retrospectively registered in the ISRTCN registry on 22/06/2019 (#ISRCTN13864650).</p