Impact of nocturnal hypoxia on glycaemic control, appetite, gut microbiota and inflammation in adults with type 2 diabetes mellitus: A single-blind cross-over trial

High altitude residents have a lower incidence of type 2 diabetes mellitus (T2DM). Therefore, we examined the effect of repeated overnight normobaric hypoxic exposure on glycaemic control, appetite, gut microbiota and inflammation in adults with T2DM. Thirteen adults with T2DM [glycated haemoglobin (HbA1c): 61.1 ± 14.1 mmol mol-1; aged 64.2 ± 9.4 years; four female] completed a single-blind, randomised, sham-controlled, cross-over study for 10 nights, sleeping when exposed to hypoxia (fractional inspired O2 [F I O 2 ${{F}_{{\mathrm{I}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$ ] = 0.155; ∼2500 m simulated altitude) or normoxic conditions (F I O 2 ${{F}_{{\mathrm{I}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$  = 0.209) in a randomised order. Outcome measures included: fasted plasma [glucose]; [hypoxia inducible factor-1α]; [interleukin-6]; [tumour necrosis factor-α]; [interleukin-10]; [heat shock protein 70]; [butyric acid]; peak plasma [glucose] and insulin sensitivity following a 2 h oral glucose tolerance test; body composition; appetite indices ([leptin], [acyl ghrelin], [peptide YY], [glucagon-like peptide-1]); and gut microbiota diversity and abundance [16S rRNA amplicon sequencing]. During intervention periods, accelerometers measured physical activity, sleep duration and efficiency, whereas continuous glucose monitors were used to assess estimated HbA1c and glucose management indicator and time in target range. Overnight hypoxia was not associated with changes in any outcome measure (P > 0.05 with small effect sizes) except fasting insulin sensitivity and gut microbiota alpha diversity, which exhibited trends (P = 0.10; P = 0.08 respectively) for a medium beneficial effect (d = 0.49; d = 0.59 respectively). Ten nights of overnight moderate hypoxic exposure did not significantly affect glycaemic control, gut microbiome, appetite, or inflammation in adults with T2DM. However, the intervention was well tolerated and a medium effect-size for improved insulin sensitivity and reduced alpha diversity warrants further investigation. KEY POINTS: Living at altitude lowers the incidence of type 2 diabetes mellitus (T2DM). Animal studies suggest that exposure to hypoxia may lead to weight loss and suppressed appetite. In a single-blind, randomised sham-controlled, cross-over trial, we assessed the effects of 10 nights of hypoxia (fractional inspired O2 ∼0.155) on glucose homeostasis, appetite, gut microbiota, inflammatory stress ([interleukin-6]; [tumour necrosis factor-α]; [interleukin-10]) and hypoxic stress ([hypoxia inducible factor 1α]; heat shock protein 70]) in 13 adults with T2DM. Appetite and inflammatory markers were unchanged following hypoxic exposure, but an increased insulin sensitivity and reduced gut microbiota alpha diversity were associated with a medium effect-size and statistical trends, which warrant further investigation using a definitive large randomised controlled trial. Hypoxic exposure may represent a viable therapeutic intervention in people with T2DM and particularly those unable or unwilling to exercise because barriers to uptake and adherence may be lower than for other lifestyle interventions (e.g. diet and exercise).

Cardiopulmonary Exercise Testing Provides Prognostic Information in Advanced Cystic Fibrosis Lung Disease

Rationale: Cardiopulmonary exercise testing (CPET) provides prognostic information in cystic fibrosis (CF); however, its prognostic value for patients with advanced CF lung disease is unknown. Objectives: To determine the prognostic value of CPET on the risk of death or lung transplant (LTX) within 2 years. Methods: We retrospectively collected data from 20 CF centers in Asia, Australia, Europe, and North America on patients with a forced expiratory volume in 1 second (FEV1) ⩽ 40% predicted who performed a cycle ergometer CPET between January 2008 and December 2017. Time to death/LTX was analyzed using mixed Cox proportional hazards regression. Conditional inference trees were modeled to identify subgroups with increased risk of death/LTX. Results: In total, 174 patients (FEV1, 30.9% ± 5.8% predicted) were included. Forty-four patients (25.5%) died or underwent LTX. Cox regression analysis adjusted for age, sex, and FEV1 revealed percentage predicted peak oxygen uptake ([Formula: see text]o2peak) and peak work rate (Wpeak) as significant predictors of death/LTX: adjusted hazard ratios per each additional 10% predicted were 0.60 (95% confidence interval, 0.43-0.90; P = 0.008) and 0.60 (0.48-0.82; P < 0.001). Tree-structured regression models, including a set of 11 prognostic factors for survival, identified Wpeak to be most strongly associated with 2-year risk of death/LTX. Probability of death/LTX was 45.2% for those with a Wpeak ⩽ 49.2% predicted versus 10.9% for those with a Wpeak > 49.2% predicted (P < 0.001). Conclusions: CPET provides prognostic information in advanced CF lung disease, and Wpeak appears to be a promising marker for LTX referral and candidate selection.

The development and internal pilot trial of a digital physical activity and emotional well-being intervention (Kidney BEAM) for people with chronic kidney disease

This trial assessed the feasibility and acceptability of Kidney BEAM, a physical activity and emotional well-being self-management digital health intervention (DHI) for people with chronic kidney disease (CKD), which offers live and on-demand physical activity sessions, educational blogs and videos, and peer support. In this mixed-methods, multicentre randomised waitlist-controlled internal pilot, adults with established CKD were recruited from five NHS hospitals and randomised 1:1 to Kidney BEAM or waitlist control. Feasibility outcomes were based upon a priori progression criteria. Acceptability was primarily explored via individual semi-structured interviews (n = 15). Of 763 individuals screened, n = 519 (68%, 95% CI 65 to 71%) were eligible. Of those eligible, n = 303 (58%, 95% CI 54-63%) did not respond to an invitation to participate by the end of the pilot period. Of the 216 responders, 50 (23%, 95% CI 18-29%) consented. Of the 42 randomised, n = 22 (10 (45%) male; 49 ± 16 years; 14 (64%) White British) were allocated to Kidney BEAM and n = 20 (12 (55%) male; 56 ± 11 years; 15 (68%) White British) to the waitlist control group. Overall, n = 15 (30%, 95% CI 18-45%) withdrew during the pilot phase. Participants completed a median of 14 (IQR 5-21) sessions. At baseline, 90-100% of outcome data (patient reported outcome measures and a remotely conducted physical function test) were completed and 62-83% completed at 12 weeks follow-up. Interview data revealed that remote trial procedures were acceptable. Participants' reported that Kidney BEAM increased their opportunity and motivation to be physically active, however, lack of time remained an ongoing barrier to engagement with the DHI. An randomised controlled trial of Kidney BEAM is feasible and acceptable, with adaptations to increase recruitment, retention and engagement.Trial registration NCT04872933. Date of first registration 05/05/2021.

Standards for the care of people with cystic fibrosis; establishing and maintaining health

This is the second in a series of four papers updating the European Cystic Fibrosis Society (ECFS) standards for the care of people with CF. This paper focuses on establishing and maintaining health. The guidance is produced using an evidence-based framework and with wide stakeholder engagement, including people from the CF community. Authors provided a narrative description of their topic and statements, which were more directive. These statements were reviewed by a Delphi exercise, achieving good levels of agreement from a wide group for all statements. This guidance reinforces the importance of a multi-disciplinary CF team, but also describes developing models of care including virtual consultations. The framework for health is reinforced, including the need for a physically active lifestyle and the strict avoidance of all recreational inhalations, including e-cigarettes. Progress with cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy is reviewed, including emerging adverse events and advice for dose reduction and interruption. This paper contains guidance that is pertinent to all people with CF regardless of age and eligibility for and access to modulator therapy.

The effect of repeated hot water immersion on insulin sensitivity, heat shock protein 70, and inflammation in individuals with type 2 diabetes mellitus

Repeated hot water immersion (HWI) can improve glycemic control in healthy individuals but data are limited for individuals with type 2 diabetes mellitus (T2DM). The present study investigated whether repeated HWI improves insulin sensitivity and inflammatory status and reduces plasma ([extracellular heat shock protein 70]) [eHSP70] and resting metabolic rate (RMR). Fourteen individuals with T2DM participated in this pre- versus postintervention study, with outcome measures assessed in fasted (≥12 h) and postprandial (2-h post-75 g glucose ingestion) states. HWI consisted of 1 h in 40°C water (target rectal temperature 38.5°C-39°C) repeated 8-10 times within a 14-day period. Outcome measures included insulin sensitivity, plasma [glucose], [insulin], [eHSP70], inflammatory markers, RMR, and substrate utilization. The HWI intervention increased fasted insulin sensitivity (QUICKI; P = 0.03) and lowered fasted plasma [insulin] (P = 0.04), but fasting plasma [glucose] (P = 0.83), [eHSP70] (P = 0.08), [IL-6] (P = 0.55), [IL-10] (P = 0.59), postprandial insulin sensitivity (P = 0.19), plasma [glucose] (P = 0.40), and [insulin] (P = 0.47) were not different. RMR was reduced by 6.63% (P < 0.05), although carbohydrate (P = 0.43) and fat oxidation (P = 0.99) rates were unchanged. This study shows that 8-10 HWIs within a 14-day period improved fasting insulin sensitivity and plasma [insulin] in individuals with T2DM, but not when glucose tolerance is challenged. HWI also improves metabolic efficiency (i.e., reduced RMR). Together these results could be clinically important and have implications for metabolic health outcomes and well-being in individuals with T2DM.NEW & NOTEWORTHY This is the first study to investigate repeated HWI to raise deep body temperature on insulin sensitivity, inflammation, eHSP70, and substrate utilization in individuals with T2DM. The principal novel findings were improvements in fasting insulin sensitivity and fasting plasma [insulin] but no change in fasting plasma [glucose], postprandial insulin sensitivity, plasma [insulin], or [glucose]. There was also no change in eHSP70, inflammatory status, or substrate utilization but there were reductions in RMR and oxygen consumption.

Heterogeneous Treatment Effects after Inspiratory Muscle Training during Recovery from Postacute COVID-19 Syndrome

PURPOSE

The objective of this study is to investigate whether heterogeneous treatment effects occur for changes in inspiratory muscle strength, perceived dyspnea, and health-related quality of life after 8 wk of unsupervised home-based inspiratory muscle training (IMT) in adults with postacute coronavirus disease 2019 (COVID-19) syndrome.

METHODS

In total, 147 adults with self-reported prior COVID-19 either completed an 8-wk home-based IMT intervention ( n = 111, 92 females, 48 ± 11 yr, 9.3 ± 3.6 months postacute COVID-19 infection) or acted as "usual care" wait list controls ( n = 36, 34 females, 49 ± 12 yr, 9.4 ± 3.2 months postacute COVID-19 infection).

RESULTS

Applying a Bayesian framework, we found clear evidence of heterogeneity of treatment response for inspiratory muscle strength: the estimated difference between standard deviations (SD) of the IMT and control groups was 22.8 cm H 2 O (75% credible interval (CrI), 4.7-37.7) for changes in maximal inspiratory pressure (MIP) and 86.8 pressure time units (75% CrI, 55.7-116.7) for sustained MIP (SMIP). Conversely, there were minimal differences in the SD between the IMT and the control group for changes in perceived dyspnea and health-related quality of life, providing no evidence of heterogeneous treatment effects. Higher cumulative power during the IMT intervention was related to changes in MIP ( β = 10.9 cm H 2 O (95% CrI, 5.3-16.8) per 1 SD) and SMIP ( β = 63.7 (32.2-95.3) pressure time units per 1 SD), clearly indicating an IMT dose response for changes in inspiratory muscle strength. Older age (>50 yr), a longer time postacute COVID-19 (>3 months), and greater severity of dyspnea at baseline were also associated with smaller improvements in inspiratory muscle strength.

CONCLUSIONS

Heterogeneous individual responses occurred after an 8-wk home-based IMT program in people with postacute COVID-19 syndrome. Consistent with standard exercise theory, larger improvements in inspiratory muscle strength are strongly related to a greater cumulative dose of IMT.

Guidance and standard operating procedures for functional exercise testing in cystic fibrosis

Regular exercise testing is recommended for all people with cystic fibrosis (PwCF). A range of validated tests, which integrate both strength and aerobic function, are available and increasingly being used. Together, these tests offer the ability for comprehensive exercise evaluation. Extensive research and expert consensus over recent years has enabled the adaptation and standardisation of a range of exercise tests to aid the understanding of the pathophysiology related to exercise limitation in PwCF and has led to the development of novel exercise tests which may be applied to PwCF. This article provides expert, opinion-based clinical practice guidance, along with test instructions, for a selection of commonly used valid tests which have documented clinimetric properties for PwCF. Importantly, this document also highlights previously used tests that are no longer suggested for PwCF and areas where research is mandated. This collaboration, on behalf of the European Cystic Fibrosis Society Exercise Working Group, represents expert consensus by a multidisciplinary panel of physiotherapists, exercise scientists and clinicians and aims to improve global standardisation of functional exercise testing of PwCF. In short, the standardised use of a small selection of tests performed to a high standard is advocated.

The effect of a novel, digital physical activity and emotional well-being intervention on health-related quality of life in people with chronic kidney disease: trial design and baseline data from a multicentre prospective, wait-list randomised controlled trial (kidney BEAM)

BACKGROUND

Physical activity and emotional self-management has the potential to enhance health-related quality of life (HRQoL), but few people with chronic kidney disease (CKD) have access to resources and support. The Kidney BEAM trial aims to evaluate whether an evidence-based physical activity and emotional wellbeing self-management programme (Kidney BEAM) leads to improvements in HRQoL in people with CKD.

METHODS

This was a prospective, multicentre, randomised waitlist-controlled trial, with health economic analysis and nested qualitative studies. In total, three hundred and four adults with established CKD were recruited from 11 UK kidney units. Participants were randomly assigned to the intervention (Kidney BEAM) or a wait list control group (1:1). The primary outcome was the between-group difference in Kidney Disease Quality of Life (KDQoL) mental component summary score (MCS) at 12 weeks. Secondary outcomes included the KDQoL physical component summary score, kidney-specific scores, fatigue, life participation, depression and anxiety, physical function, clinical chemistry, healthcare utilisation and harms. All outcomes were measured at baseline and 12 weeks, with long-term HRQoL and adherence also collected at six months follow-up. A nested qualitative study explored experience and impact of using Kidney BEAM.

RESULTS

340 participants were randomised to Kidney BEAM (n = 173) and waiting list (n = 167) groups. There were 96 (55%) and 89 (53%) males in the intervention and waiting list groups respectively, and the mean (SD) age was 53 (14) years in both groups. Ethnicity, body mass, CKD stage, and history of diabetes and hypertension were comparable across groups. The mean (SD) of the MCS was similar in both groups, 44.7 (10.8) and 45.9 (10.6) in the intervention and waiting list groups respectively.

CONCLUSION

Results from this trial will establish whether the Kidney BEAM self management programme is a cost-effective method of enhancing mental and physical wellbeing of people with CKD.

TRIAL REGISTRATION

NCT04872933. Registered 5th May 2021.

Survey of exercise testing and training in cystic fibrosis clinics in the UK: a decade of progress

OBJECTIVES

Regular exercise testing is recommended for people with cystic fibrosis (pwCF), as is the provision and regular review of exercise training programmes. A previous survey on exercise testing and training for pwCF in the UK was conducted over a decade ago. With the landscape of CF changing considerably during this time, this survey aimed to evaluate UK-based exercise testing and training practices for pwCF a decade on.

DESIGN

Cross-sectional, online survey.

PARTICIPANTS

A survey was distributed electronically to UK CF clinics and completed by the individual primarily responsible for exercise services. Descriptive statistics and qualitative analyses were undertaken.

RESULTS

In total, 31 CF centres participated, representing ~50% of UK specialist clinics. Of these, 94% reported using exercise testing, 48% of which primarily use cardiopulmonary exercise testing. Exercise testing mostly occurs at annual review (93%) and is most often conducted by physiotherapists (62%). A wide variation in protocols, exercise modalities, normative reference values and cut-offs for exercise-induced desaturation are currently used. All centres reportedly discuss exercise training with pwCF; 94% at every clinic appointment. However, only 52% of centres reportedly use exercise testing to inform individualised exercise training. Physiotherapists typically lead discussions around exercise training (74%).

CONCLUSIONS

These data demonstrate that the majority of respondent centres in the UK now offer some exercise testing and training advice for pwCF, representing a marked improvement over the past decade. However, continued efforts are now needed to standardise exercise practices, particularly regarding field testing practices and the translation of test results into personalised training programmes for pwCF.

Exploring patients' experiences of the impact of dialysis therapies on quality of life and wellbeing

BACKGROUND

When people with chronic kidney disease reach kidney failure, renal replacement therapy is usually required to improve symptoms and maintain life. Although in-centre haemodialysis is most commonly used for this purpose, other forms of dialysis are available, including home haemodialysis and peritoneal dialysis.

OBJECTIVES

We aimed to explore the experiences of adults living with chronic kidney disease who were either approaching the need for dialysis or had reached kidney failure and were receiving a form of dialysis. In particular, we explored how different forms of dialysis affect their quality of life, wellbeing, and physical activity.

METHODS

Individual semistructured interviews were conducted with 40 adults with kidney failure, comprising four groups (n = 10 each): those receiving in-centre haemodialysis, home haemodialysis or peritoneal dialysis, or predialysis. Interviews were transcribed verbatim, thematically analysed, and then composite vignettes were subsequently developed to present a rich narrative of the collective experiences of each group.

FINDINGS

Compared with adults who were predialysis, quality of life and wellbeing improved upon initiation of their home haemodialysis or peritoneal dialysis. Conversely, minimal improvement was perceived by those receiving in-centre haemodialysis. Low physical activity was reported across all four groups, although those receiving home haemodialysis and peritoneal dialysis reported a greater desire and ability to be physically active than those in-centre.

CONCLUSION

These findings highlight that dialysis modalities not requiring regular hospital attendance (i.e., home haemodialysis and peritoneal dialysis) improve independence, quality of life, wellbeing, and can facilitate a more physically active lifestyle.

Battling the unknown: Using composite vignettes to portray lived experiences of COVID-19 and long-COVID

Understanding the day-to-day lived experiences of individuals who have had or are still recovering from Coronavirus Disease-19 (COVID-19), whilst a complex challenge, presents the opportunity to listen and learn. Composite vignettes provide a novel approach to explore and present descriptive portrayals of the most commonly derived experiences and recovery journeys. The thematic analysis of 47 shared accounts (semi-structured interviews with adults aged ≥18 years; 40 females; 6-11 months post-COVID-19 infection) produced a series of four intricate character stories written through the lens of a single individual. Each vignette gives a voice to and captures a different experience trajectory. From the point of initial symptom development onwards, the vignettes depict how COVID-19 has affected everyday lives, focusing on the secondary non-biological socio-psychological effects and implications. The vignettes highlight in participants' own words: i) the potential negative implications of not addressing the psychological effects of COVID-19; ii) the lack of symptom and recovery linearity; iii) the ongoing 'lottery' of access to healthcare services; and iv) the highly variable, yet generally devastating, impacts that COVID-19 and consequent long-COVID has had across multiple facets of daily living.

Exercise as an Airway Clearance Technique in people with Cystic Fibrosis (ExACT-CF): rationale and study protocol for a randomised pilot trial

Background

Chest physiotherapy is an established cornerstone of care for people with cystic fibrosis (pwCF), but is often burdensome. Guidelines recommend at least one chest physiotherapy session daily, using various airway clearance techniques (ACTs). Exercise (with huffs and coughs) may offer an alternative ACT, however the willingness of pwCF to be randomised into a trial needs testing. The 'ExACT-CF: Exercise as an Airway Clearance Technique in people with Cystic Fibrosis' trial will test the feasibility of recruiting pwCF to be randomised to continue usual care (chest physiotherapy) or replace it with exercise ACT (ExACT) for 28-days. Secondary aims include determining the short-term clinical impact (and safety) of stopping routine chest physiotherapy and replacing it with ExACT, and effects on physical activity, sleep, mood, quality of life and treatment burden, alongside preliminary health economic measures and acceptability.

Methods

Multi-centre, two-arm, randomised (1:1 allocation using minimisation), pilot trial at two sites. Fifty pwCF (≥10 years, FEV 1 >40% predicted, stable on Elexacaftor/Tezacaftor/Ivacaftor (ETI)) will be randomised to an individually-customised ExACT programme (≥once daily aerobic exercise of ≥20-minutes duration at an intensity that elicits deep breathing, with huffs and coughs), or usual care. After baseline assessments, secondary outcomes will be assessed after 28-days, with additional home lung function and exacerbation questionnaires at 7, 14 and 21-days, physical activity and sleep monitoring throughout, and embedded qualitative and health-economic components. Feasibility measures include recruitment, retention, measurement completion, adverse events, interviews exploring the acceptability of trial procedures, and a trial satisfaction questionnaire.

Discussion

Co-designed with the UK CF community, the ExACT-CF pilot trial is the first multi-centre RCT to test the feasibility of recruiting pwCF stable on ETI into a trial investigating ExACT. This pilot trial will inform the feasibility, design, management, likely external validity for progression to a main phase randomised controlled trial.

Registration

Clinicaltrials.gov ( NCT05482048).

Perceptions of inspiratory muscle training in adults recovering from COVID-19

Post COVID-19 condition can occur following infection with SARS-CoV-2 and is characterised by persistent symptoms, including fatigue, breathlessness and cognitive dysfunction, impacting everyday functioning. This study explored how people living with post COVID-19 experienced an eight-week inspiratory muscle training (IMT) rehabilitation programme. Individualised semi-structured interviews with 33 adults (29 female; 49 ± 10 years; 6–11 months post-infection) explored expectations of IMT prior to the intervention, and post intervention interviews explored perceptions of IMT and its impact on recovery. Inductive thematic analysis was used to analyse the data. IMT helped many to feel proactive in managing their symptoms and was associated with perceived improvements in respiratory symptoms, exercise and work capacity, and daily functioning. IMT was well perceived and offers significant potential for use as part of a holistic recovery programme, although it is important to consider the complex, varied symptoms of post COVID-19, necessitating an individually tailored rehabilitation approach.

Elexacaftor-Tezacaftor-Ivacaftor improves exercise capacity in adolescents with cystic fibrosis

OBJECTIVE

Elexacaftor/Tezacaftor/Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) modulator with the potential to improve exercise capacity. This case series of three adolescents with CF aimed to investigate whether 6 weeks treatment with Elexacaftor/Tezacaftor/Ivacaftor could improve exercise capacity in CFTR modulator naive adolescents with CF.

METHODS

Three adolescents (14.0 ± 1.4 years) with CF (FEV₁ % predicted: 62.5 ± 17.1; F508del/F508del genotype) completed an exhaustive maximal cardiopulmonary exercise test on a cycle ergometer to determine peak oxygen uptake ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> </mml:mrow> <mml:annotation>$\dot{{\rm{V}}}$</mml:annotation></mml:semantics> </mml:math> O_2peak ) and measure changes in gas exchange and ventilation during exercise at 6 weeks. We also analyzed wrist-worn device-based physical activity (PA) data in two of the three cases. Validated acceleration thresholds were used to quantify time spent in each PA intensity category.

RESULTS

Clinically meaningful improvements in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:mover><mml:mi>V</mml:mi> <mml:mo>̇</mml:mo></mml:mover> </mml:mrow> <mml:annotation>$\dot{{\rm{V}}}$</mml:annotation></mml:semantics> </mml:math> O_2peak were observed in all three cases (+17.6%, +52.4%, and +32.9%, respectively), with improvements greatest in those with more severe lung disease and lower fitness at baseline. Although lung function increased in all cases, inconsistent changes in markers of ventilatory and peripheral muscle efficiency likely suggest different mechanisms of improvement in this case group of adolescents with CF. Device-based analysis of PA was variable, with one case increasing and one case decreasing.

CONCLUSION

In this case series, we have observed, for the first time, improvements in exercise capacity following 6 weeks of treatment with Elexacaftor/Tezacaftor/Ivacaftor. Improvements were greatest in the presence of more severe CF lung disease and lower aerobic fitness at baseline. The mechanism(s) responsible for these changes warrant further investigation in larger trials.

Experiences of adults living with a kidney transplant-Effects on physical activity, physical function, and quality of life: A descriptive phenomenological study

BACKGROUND

Although kidney transplantation is the best treatment for kidney failure, scarce research has examined its effects on physical activity, physical function and quality of life.

OBJECTIVES

To investigate the experiences of a group of adults living with advanced kidney disease focusing on quality of life, physical activity and function and to see how findings differ in a group of kidney transplant recipients.

APPROACH

Individual semi-structured interviews were conducted with adults with advanced kidney disease (n = 10; 70.5 ± 8.9 years) and adults who had received a kidney transplant (n = 10; 50.7 ± 11.5 years; transplant age: 42.7 ± 20.9 months). Interviews were transcribed verbatim, thematically analysed and composite vignettes developed.

FINDINGS

Individuals with advanced kidney disease described a sense of loss and alteration to their life plans. Kidney transplant recipients reported increased freedom, independence and a return to near normality, with improved quality of life, physical activity and function compared with their pre-transplant lives. However, transplant recipients also described living with anxiety about the health of their transplant and fear it may fail.

CONCLUSION

Whilst adults living with advanced kidney disease often experience a reduced quality of life, physical activity and function, kidney transplantation can help facilitate a return to pre-disease levels of physical activity, physical function and quality of life. However, transplant recipients also reported living with anxiety around their new kidney failing. This study demonstrates the variability in the lived experiences of adults living with advanced kidney disease or a kidney transplant and highlights the need for patient-centred care.

The impact of COVID‐19 upon the delivery of exercise services within cystic fibrosis clinics in the United Kingdom

Objectives

The COVID‐19 pandemic has resulted in unprecedent changes to clinical practice, and as the impact upon delivery of exercise services for people with cystic fibrosis (CF) in the United Kingdom was unknown, this was characterised via a national survey.

Methods

An electronic survey was distributed to healthcare professionals involved in the exercise management of CF via established professional networks.

Results

In total, 31 CF centres participated. Findings included significant reductions in exercise testing and widespread adaptation to deliver exercise training using telehealth methods. Promisingly, 71% stated that they would continue using virtual methods of engaging patients in future practice.

Conclusion

These findings highlight adaptation to the COVID‐19 pandemic and the need to develop sustainable and standardised telehealth services to manage patients moving forwards.

Inspiratory Muscle Training Enhances Recovery Post COVID-19: A Randomised Controlled Trial

Background

Many people recovering from coronavirus disease 2019 (COVID-19) experience prolonged symptoms, particularly breathlessness. We urgently need to identify safe and effective COVID-19 rehabilitative strategies. The aim of the current study was to investigate the potential rehabilitative role of inspiratory muscle training (IMT).

Methods

281 adults (age 46.6±12.2 years; 88% female) recovering from self-reported COVID-19 (9.0±4.2 months post-acute infection) were randomised 4:1 to an 8-week IMT or a “usual care” waitlist control arm. Health-related quality-of-life and breathlessness questionnaires (King's Brief Interstitial Lung Disease (K-BILD) and Transition Dyspnoea Index (TDI)), respiratory muscle strength, and fitness (Chester Step Test) were assessed pre- and post-intervention. The primary end-point was K-BILD total score, with the K-BILD domains and TDI being key secondary outcomes.

Results

According to intention to treat, there was no difference between groups in K-BILD total score post-intervention (control: 59.5±12.4; IMT: 58.2±12.3; p<0.05) but IMT elicited clinically meaningful improvements in the K-BILD domains for breathlessness (control: 59.8±12.6; IMT: 62.2±16.2; p<0.05) and chest symptoms (control: 59.2±18.7; IMT: 64.5±18.2; p<0.05), along with clinically meaningful improvements in breathlessness according to TDI (control: 0.9±1.7 versus 2.0±2.0; p<0.05). IMT also improved respiratory muscle strength and estimated aerobic fitness.

Conclusions

IMT may represent an important home-based rehabilitation strategy for wider implementation as part of COVID-19 rehabilitative strategies. Given the diverse nature of long COVID, further research is warranted on the individual responses to rehabilitation; the withdrawal rate herein highlights that no one strategy is likely to be appropriate for all.

IMT can significantly improve breathlessness and respiratory muscle function in people with long COVID, and represents an effective, home-based rehabilitation strategy that could be widely implemented as part of COVID-19 recovery strategieshttps://bit.ly/3HiEyz0

The physiological and clinical importance of cardiorespiratory fitness in people with abdominal aortic aneurysm

New Findings

What is the topic of this review?

This review focuses on the physiological impact of abdominal aortic aneurysm (AAA) on cardiorespiratory fitness and the negative consequences of low fitness on clinical outcomes in AAA. We also discuss the efficacy of exercise training for improving cardiorespiratory fitness in AAA.

What advances does it highlight?

We demonstrate the negative impact of low fitness on disease progression and clinical outcomes in AAA. We highlight potential mechanistic determinants of low fitness in AAA and present evidence that exercise training can be an effective treatment strategy for improving cardiorespiratory fitness, postoperative mortality and disease progression.

Abstract

An abdominal aortic aneurysm (AAA) is an abnormal enlargement of the aorta, below the level of the renal arteries, where the aorta diameter increases by >50%. As an aneurysm increases in size, there is a progressive increase in the risk of rupture, which ranges from 25 to 40% for aneurysms >5.5 cm in diameter. People with AAA are also at a heightened risk of cardiovascular events and associated mortality. Cardiorespiratory fitness is impaired in people with AAA and is associated with poor (postoperative) clinical outcomes, including increased length of hospital stay and postoperative mortality after open surgical or endovascular AAA repair. Although cardiorespiratory fitness is a well‐recognized prognostic marker of cardiovascular health and mortality, it is not assessed routinely, nor is it included in current clinical practice guidelines for the management of people with AAA. In this review, we discuss the physiological impact of AAA on cardiorespiratory fitness, in addition to the consequences of low cardiorespiratory fitness on clinical outcomes in people with AAA. Finally, we summarize current evidence for the effect of exercise training interventions on cardiorespiratory fitness in people with AAA, including the associated improvements in postoperative mortality, AAA growth and cardiovascular risk. Based on this review, we propose that cardiorespiratory fitness should be considered as part of the routine risk assessment and monitoring of people with AAA and that targeting improvements in cardiorespiratory fitness with exercise training might represent a viable adjunct treatment strategy for reducing postoperative mortality and disease progression.

The Exeter Activity Unlimited statement on physical activity and exercise for cystic fibrosis: methodology and results of an international, multidisciplinary, evidence-driven expert consensus

Background

The roles of physical activity (PA) and exercise within the management of cystic fibrosis (CF) are recognised by their inclusion in numerous standards of care and treatment guidelines. However, information is brief, and both PA and exercise as multi-faceted behaviours require extensive stakeholder input when developing and promoting such guidelines.

Method

On 30^th June and 1^st July 2021, 39 stakeholders from 11 countries, including researchers, healthcare professionals and patients participated in a virtual conference to agree an evidence-based and informed expert consensus about PA and exercise for people with CF. This consensus presents the agreement across six themes: (i) patient and system centred outcomes, (ii) health benefits, iii) measurement, (iv) prescription, (v) clinical considerations, and (vi) future directions. The consensus was achieved by a stepwise process, involving: (i) written evidence-based synopses; (ii) peer critique of synopses; (iii) oral presentation to consensus group and peer challenge of revised synopses; and (iv) anonymous voting on final proposed synopses for adoption to the consensus statement.

Results

The final consensus document includes 24 statements which surpassed the consensus threshold (>80% agreement) out of 30 proposed statements.

Conclusion

This consensus can be used to support health promotion by relevant stakeholders for people with CF.

CFTR limits F-actin formation and promotes morphological alignment with flow in human lung microvascular endothelial cells

Micro- and macrovascular endothelial dysfunction in response to shear stress has been observed in cystic fibrosis (CF), and has been associated with inflammation and oxidative stress. We tested the hypothesis that the cystic fibrosis transmembrane conductance regulator (CFTR) regulates endothelial actin cytoskeleton dynamics and cellular alignment in response to flow. Human lung microvascular endothelial cells (HLMVEC) were cultured with either the CFTR inhibitor GlyH-101 (20 µM) or CFTRinh-172 (20 µM), tumor necrosis factor (TNF)-α (10 ng/ml) or a vehicle control (0.1% dimethyl sulfoxide) during 24 and 48 h of exposure to shear stress (11.1 dynes/cm2 ) or under static control conditions. Cellular morphology and filamentous actin (F-actin) were assessed using immunocytochemistry. [Nitrite] and endothelin-1 ([ET-1]) were determined in cell culture supernatant by ozone-based chemiluminescence and ELISA, respectively. Treatment of HLMVECs with both CFTR inhibitors prevented alignment of HLMVEC in the direction of flow after 24 and 48 h of shear stress, compared to vehicle control (both p < 0.05). Treatment with TNF-α significantly increased total F-actin after 24 h versus control (p < 0.05), an effect that was independent of shear stress. GlyH-101 significantly increased F-actin after 24 h of shear stress versus control (p < 0.05), with a significant (p < 0.05) reduction in cortical F-actin under both static and flow conditions. Shear stress decreased [ET-1] after 24 h (p < 0.05) and increased [nitrite] after 48 h (p < 0.05), but neither [nitrite] nor [ET-1] was affected by GlyH-101 (p > 0.05). CFTR appears to limit cytosolic actin polymerization, while maintaining a cortical rim actin distribution that is important for maintaining barrier integrity and promoting alignment with flow, without effects on endothelial nitrite or ET-1 production.

'I Live a Kind of Shadow Life': Individual Experiences of COVID-19 Recovery and the Impact on Physical Activity Levels

Understanding of strategies to support individuals recovering from coronavirus disease 2019 (COVID-19) is limited. ‘Long COVID’ is a multisystem disease characterised by a range of respiratory, gastrointestinal, cardiovascular, neurological, and musculoskeletal symptoms extending beyond 12 weeks. The aim of this study was to explore individuals’ experiences of recovering from COVID-19 to provide a better understanding of the acute and long-term impact of the disease on physical activity (PA). Individualised semi-structured interviews were conducted with 48 adults recovering from COVID-19 at 6–11 months post-infection. An inductive thematic analysis approach was used, reaching saturation at 14 interviews (10 female; 47 ± 7 years). Four overarching themes were identified: (i) Living with COVID-19, including managing activities of daily living; (ii) Dealing with the Unknown and self-management strategies; (iii) Re-introducing physical activity; and (iv) Challenges of returning to work. The return to PA, whether through activities of daily living, work or exercise, is often associated with the exacerbation of symptoms, presenting a range of challenges for individuals recovering from COVID-19. Individually tailored support is therefore required to address the unique challenges posed by COVID-19.

Rethinking physical exercise training in the modern era of cystic fibrosis: A step towards optimising short-term efficacy and long-term engagement

Exercise is considered as an important component of the package of care delivered to people with cystic fibrosis (pwCF). However, despite the well-known short-term physiological and psychological benefits, training effects are heterogenous and the transfer of structured exercise programmes to the daily life of pwCF is challenging. Training concepts and strategies developed over the last decades must be adapted to consider the aging population of pwCF with associated comorbidities, and also a new generation of young pwCF that are healthier than ever. In the present review we propose a new framework for optimising the choice among available exercise training procedures and we provide a theoretical and scientifically justified rationale for considering and testing new exercise training modalities. We propose a multidisciplinary approach, considering various physiological, psychological and logistical factors, with the aim to increase effects of exercise training and build positive long-term exercise behaviour.

The impact of plasma 25-hydroxyvitamin D on pulmonary function and exercise physiology in cystic fibrosis: A multicentre retrospective study

BACKGROUND

A 25-hydroxyvitamin D (25OHD) may exert immunomodulatory effects on respiratory health, which may translate to improvements in exercise physiology. Thus, we aimed to investigate whether plasma 25OHD is associated with lung function and aerobic fitness in people with cystic fibrosis (pwCF).

METHODS

A multicentre retrospective review of pwCF (> 9 years old) attending the Royal Hospital for Sick Children (Edinburgh) or Wessex CF-Unit (Southampton) was performed between July 2017 and October 2019. Demographic and clinical data were collected. Plasma 25OHD measured closest in time to clinical cardiopulmonary exercise testing and/or spirometry [forced expiratory volume (FEV₁ )% predicted] was recorded. Pancreatic insufficiency was diagnosed based on faecal elastase of < 100 µg g^-1 . We performed multiple-regression analysis with aerobic fitness outcomes [peak oxygen uptake (VO_2 peak )] and FEV₁ % predicted as primary outcomes.

RESULTS

Ninety pwCF [mean ± SD age: 19.1 ± 8.6 years, 54 (60%) children, 48 (53%) males and 88 (98%) Caucasian] were included. 25OHD deficiency and insufficiency was 15 (17%) and 44 (49%), respectively. 25OHD deficiency and insufficiency was significantly associated with pancreatic insufficiency (χ²  = 4.8, p = 0.02). Plasma 25OHD was not significantly associated with FEV₁ % predicted (r²  = 0.06, p = 0.42, 95% CI = -0.09 to 0.19) or VO_2 peak (r²  = 0.04, p = 0.07, 95% CI = -011 to 0.005) in all pwCF. However, 25OHD was significantly associated with both FEV₁ % (r²  = 0.15, p = 0.02, 95% CI = 1.99-2.64) and VO_2 peak (r²  = 0.13, p = 0.05, 95% CI = -0.26 to -0.005) in the paediatric cohort.

CONCLUSIONS

We showed that 25OHD is associated with improved lung function and aerobic fitness in children and adolescents with CF. Mechanistic and high-quality prospective studies including both lung function and aerobic fitness as primary outcomes are now warranted.

Timing of acute passive heating on glucose tolerance and blood pressure in people with type 2 diabetes: a randomized, balanced crossover, control trial

Type 2 diabetes mellitus (T2DM) is characterized by chronic hyperglycemia and progressive insulin resistance, leading to macro and microvascular dysfunction. Passive heating has potential to improve glucose homeostasis and act as an exercise mimetic. We assessed the effect of acute passive heating before or during an oral glucose tolerance test (OGTT) in people with T2DM. Twelve people with T2DM were randomly assigned to the following three conditions: 1) 3-h OGTT (control), 2) 1-h passive heating (40°C water) 30 min before an OGTT (HOT-OGTT), and 3) 1-h passive heating (40°C water) 30 min after commencing an OGTT (OGTT-HOT). Blood glucose concentration, insulin sensitivity, extracellular heat shock protein 70 (eHSP70), total energy expenditure (TEE), heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were recorded. Passive heating did not alter blood glucose concentration [control: 1,677 (386) arbitrary units (AU), HOT-OGTT: 1,797 (340) AU, and OGTT-HOT: 1,662 (364) AU, P = 0.28], insulin sensitivity (P = 0.15), or SBP (P = 0.18) but did increase eHSP70 concentration in both heating conditions [control: 203.48 (110.81) pg·mL^-1; HOT-OGTT: 402.47 (79.02) pg·mL^-1; and OGTT-HOT: 310.00 (60.53) pg·mL^-1, P < 0.001], increased TEE (via fat oxidation) in the OGTT-HOT condition [control: 263 (33) kcal, HOT-OGTT: 278 (40) kcal, and OGTT-HOT: 304 (38) kcal, P = 0.001], increased HR in both heating conditions (P < 0.001), and reduced DBP in the OGTT-HOT condition (P < 0.01). Passive heating in close proximity to a glucose challenge does not alter glucose tolerance but does increase eHSP70 concentration and TEE and reduce blood pressure in people with T2DM.NEW & NOTEWORTHY This is the first study to investigate the timing of acute passive heating on glucose tolerance and extracellular heat shock protein 70 concentration ([eHSP70]) in people with type 2 diabetes. The principal novel findings from this study were that both passive heating conditions: 1) did not reduce the area under the curve or peak blood glucose concentration, 2) elevated heart rate, and 3) increased [eHSP70], which was blunted by glucose ingestion, while passive heating following glucose ingestion, 4) increased total energy expenditure, and 5) reduced diastolic blood pressure.

Understanding the Impact of Initial COVID-19 Restrictions on Physical Activity, Wellbeing and Quality of Life in Shielding Adults with End-Stage Renal Disease in the United Kingdom Dialysing at Home versus In-Centre and Their Experiences with Telemedicine

Early in the coronavirus-2019 (COVID-19) containment strategy, people with end-stage renal disease (ESRD) were identified as extremely clinically vulnerable and subsequently asked to 'shield' at home where possible. The aim of this study was to investigate how these restrictions and the transition to an increased reliance on telemedicine within clinical care of people living with kidney disease impacted the physical activity (PA), wellbeing and quality of life (QoL) of adults dialysing at home (HHD) or receiving in-centre haemodialysis (ICHD) in the UK. Individual semistructured telephone interviews were conducted with adults receiving HHD (n = 10) or ICHD (n = 10), were transcribed verbatim and, subsequently, thematically analysed. As result of the COVID-19 restrictions, PA, wellbeing and QoL of people with ESRD were found to have been hindered. However, widespread support for the continued use of telemedicine was strongly advocated and promoted independence and satisfaction in patient care. These findings highlight the need for more proactive care of people with ESRD if asked to shield again, as well as increased awareness of safe and appropriate PA resources to help with home-based PA and emotional wellbeing.

Oxygen transport and utilisation during exercise in cystic fibrosis: contributors to exercise intolerance

NEW FINDINGS

What is the topic of this review? This review highlights the central and peripheral mechanisms that alter oxygen transport and utilisation and thereby contribute to exercise limitation in people with cystic fibrosis, considering also viable therapeutic targets for intervention. What advances does it highlight? Although traditionally considered a respiratory condition, pathological intramuscular and cardiovascular changes in people with cystic fibrosis appear to be key determinants of exercise intolerance up until the later stages of respiratory disease. Even young, habitually active patients with normal lung function experience multisystemic abnormalities, which play a role in exercise intolerance.

ABSTRACT

Cystic fibrosis (CF) is a complex condition, commonly associated with exercise limitation. The mechanisms responsible for this in CF are of interest, given that lower aerobic fitness is associated with an increased risk of being hospitalised with pulmonary exacerbation, a poorer quality of life and a poorer prognosis. Pathophysiological changes in lung function are considered central to CF, and may contribute to exercise limitation. However, it is now clear that the pathogenesis of exercise limitation in this population is multifactorial, with alterations in cardiovascular, muscle and pulmonary function contributing. Whilst some of these changes are attributable to respiratory disease per se, the CF transmembrane conductance regulator protein is also found in skeletal muscle and the vascular endothelium and can directly alter central and localised oxygen delivery, as well as the ability to effectively extract and utilise oxygen at the myocyte level. Since intense exercise poses considerable challenges to arterial oxygen content and/or blood flow and its supply to the working skeletal muscle, evaluating the exercise physiology of people with CF has helped us understand the mechanisms underlying exercise intolerance. Through several investigations over recent years, we have collectively demonstrated that people with CF exhibit reduced skeletal muscle oxygen extraction and utilisation during exercise, with a lesser contribution from haemodynamic or chronotropic mechanisms. Taken together, our findings highlight the importance of targeting mechanisms of skeletal muscle oxygen utilisation in CF to improve exercise tolerance and we offer potential therapeutic interventional strategies.

Circulating biomarkers of antioxidant status and oxidative stress in people with cystic fibrosis: A systematic review and meta-analysis

Introduction

Oxidative stress may play an important role in the pathophysiology of cystic fibrosis (CF). This review aimed to quantify CF-related redox imbalances.

Methods

Systematic searches of the Medline, CINAHL, CENTRAL and PsycINFO databases were conducted. Mean content of blood biomarkers from people with clinically-stable CF and non-CF controls were used to calculate the standardized mean difference (SMD) and 95% confidence intervals (95% CI).

Results

Forty-nine studies were eligible for this review including a total of 1792 people with CF and 1675 controls. Meta-analysis revealed that protein carbonyls (SMD: 1.13, 95% CI: 0.48 to 1.77), total F₂-isoprostane 8-iso-prostaglandin F_2α (SMD: 0.64, 95% CI: 0.23 to 1.05) and malondialdehyde (SMD: 1.34, 95% CI: 0.30 to 2.39) were significantly higher, and vitamins A (SMD: −0.66, 95% CI -1.14 to −0.17) and E (SMD: −0.74, 95% CI: −1.28 to −0.20), β-carotene (SMD: −1.80, 95% CI: −2.92 to −0.67), lutein (SMD: −1.52, 95% CI: −1.83 to −1.20) and albumin (SMD: −0.98, 95% CI: −1.68 to −0.27) were significantly lower in the plasma or serum of people with CF versus controls.

Conclusions

This systematic review and meta-analysis found good evidence for reduced antioxidant capacity and elevated oxidative stress in people with clinically-stable CF.

•

Blood biomarkers of oxidative stress were elevated in stable CF vs non-CF controls.

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Lipid peroxidation was positively correlated with age and immune cell count in CF.

•

Antioxidants vitamins A & E, β-carotene, lutein and albumin were lower in stable CF.

•

Antioxidants were positively correlated with body mass index and lung function in CF.

Practical Considerations for Assessing Pulmonary Gas Exchange and Ventilation During Flume Swimming Using the MetaSwim Metabolic Cart

Lomax, M, Mayger, B, Saynor, ZL, Vine, C, and Massey, HC. Practical considerations for assessing pulmonary gas exchange and ventilation during flume swimming using the MetaSwim metabolic cart. J Strength Cond Res 33(7): 1941-1953, 2019-The MetaSwim (MS) metabolic cart can assess pulmonary gas exchange and ventilation in aquatic environments. The aims of this study were: (a) to determine the agreement between minute ventilation (VE), pulmonary oxygen uptake (VO2), and carbon dioxide output (VCO2) using the MS and Douglas bag (DB) methods during flume swimming; and (b) to assess the repeatability of these and other MS-derived parameters. Sixteen trained swimmers completed a combined incremental and supramaximal verification cardiopulmonary swimming test to determine maximal VO2, 2 progressive intensity swimming tests during which MS and DB measurements were made (agreement protocol), and 3-4 constant-velocity submaximal swimming tests during which only the MS was used (repeatability protocol). Agreement was determined using limits of agreement (LoA), bias, random error, and 95% confidence intervals with systematic bias assessed using paired samples t-tests. Within-trial and between-trial repeatability were determined using the coefficient of variation (CV) and the repeatability coefficient (CR). Where data were heteroscedastic, LoA and CR were log-transformed, antilogged, and displayed as ratios. MetaSwim underestimated peak VO2 and VCO2 (≤0.39 L·min) and VE (9.08 L·min), whereas submaximal values varied between 2 and 5% for CV and ±1.09-1.22 for ratio CR. The test-retest CV during constant-velocity swimming for VE, tidal volume, breathing frequency, VO2, VCO2, and end-tidal pressures of O2 and CO2 was <9% (ratio CR of ±1.09-1.34). Thus, the MS and DB cannot be used interchangeably. Whether the MS is suitable for evaluating ventilatory and pulmonary responses in swimming will depend on the size of effect required.

Relationship between (non)linear phase II pulmonary oxygen uptake kinetics with skeletal muscle oxygenation and age in 11-15 year olds

NEW FINDINGS

What is the central question of this study? Do the phase II parameters of pulmonary oxygen uptake ( V ̇ O 2 ) kinetics display linear, first-order behaviour in association with alterations in skeletal muscle oxygenation during step cycling of different intensities or when exercise is initiated from an elevated work rate in youths. What is the main finding and its importance? Both linear and non-linear features of phase II V ̇ O 2 kinetics may be determined by alterations in the dynamic balance between microvascular O₂ delivery and utilization in 11-15 year olds. The recruitment of higher-order (i.e. type II) muscle fibres during 'work-to-work' cycling might be responsible for modulating V ̇ O 2 kinetics with chronological age.

ABSTRACT

This study investigated in 19 male youths (mean age: 13.6 ± 1.1 years, range: 11.7-15.7 years) the relationship between pulmonary oxygen uptake ( V ̇ O 2 ) and muscle deoxygenation kinetics during moderate- and very heavy-intensity 'step' cycling initiated from unloaded pedalling (i.e. U → M and U → VH) and moderate to very heavy-intensity step cycling (i.e. M → VH). Pulmonary V ̇ O 2 was measured breath-by-breath along with the tissue oxygenation index (TOI) of the vastus lateralis using near-infrared spectroscopy. There were no significant differences in the phase II time constant ( τ V ̇ O 2 p ) between U → M and U → VH (23 ± 6 vs. 25 ± 7 s; P = 0.36); however, the τ V ̇ O 2 p was slower during M → VH (42 ± 16 s) compared to other conditions (P < 0.001). Quadriceps TOI decreased with a faster (P < 0.01) mean response time (MRT; i.e. time delay + τ) during U → VH (14 ± 2 s) compared to U → M (22 ± 4 s) and M → VH (20 ± 6 s). The difference (Δ) between the τ V ̇ O 2 p and MRT-TOI was greater during U → VH compared to U → M (12 ± 7 vs. 2 ± 7 s, P < 0.001) and during M → VH (23 ± 15 s) compared to other conditions (P < 0.02), suggesting an increased proportional speeding of fractional O₂ extraction. The slowing of the τ V ̇ O 2 p during M → VH relative to U → M and U → VH correlated positively with chronological age (r = 0.68 and 0.57, respectively, P < 0.01). In youths, 'work-to-work' transitions slowed microvascular O₂ delivery-to-O₂ utilization with alterations in phase II V ̇ O 2 dynamics accentuated between the ages of 11 and 15 years.

"Beet" the cold: beetroot juice supplementation improves peripheral blood flow, endothelial function, and anti-inflammatory status in individuals with Raynaud's phenomenon

Raynaud's phenomenon (RP) is characterized by recurrent transient peripheral vasospasm and lower nitric oxide (NO) bioavailability in the cold. We investigated the effect of nitrate-rich beetroot juice (BJ) supplementation on 1) NO-mediated vasodilation, 2) cutaneous vascular conductance (CVC) and skin temperature (T_sk) following local cooling, and 3) systemic anti-inflammatory status. Following baseline testing, 23 individuals with RP attended four times, in a double-blind, randomized crossover design, following acute and chronic (14 days) BJ and nitrate-depleted beetroot juice (NDBJ) supplementation. Peripheral T_sk and CVC were measured during and after mild hand and foot cooling, and during transdermal delivery of acetylcholine and sodium nitroprusside. Markers of anti-inflammatory status were also measured. Plasma nitrite concentration ([nitrite]) was increased in the BJ conditions (P < 0.001). Compared with the baseline visit, thumb CVC was greater following chronic-BJ (Δ2.0 flux/mmHg, P = 0.02) and chronic-NDBJ (Δ1.45 flux/mmHg, P = 0.01) supplementation; however, no changes in T_sk were observed (P > 0.05). Plasma [interleukin-10] was greater, pan endothelin and systolic and diastolic blood pressure (BP) were reduced, and forearm endothelial function was improved, by both BJ and NDBJ supplementation (P < 0.05). Acute and chronic BJ and NDBJ supplementation improved anti-inflammatory status, endothelial function and blood pressure (BP). CVC following cooling increased post chronic-BJ and chronic-NDBJ supplementation, but no effect on T_sk was observed. The key findings are that beetroot supplementation improves thumb blood flow, improves endothelial function and anti-inflammatory status, and reduces BP in people with Raynaud's.NEW & NOTEWORTHY This is the first study to examine the effect of dietary nitrate supplementation in individuals with Raynaud's phenomenon. The principal novel findings from this study were that both beetroot juice and nitrate-depleted beetroot juice 1) increased blood flow in the thumb following a cold challenge; 2) enhanced endothelium-dependent and -independent vasodilation in the forearm; 3) reduced systolic and diastolic blood pressure, and pan-endothelin concentration; and 4) improved inflammatory status in comparison to baseline.

Cardiopulmonary exercise testing with supramaximal verification produces a safe and valid assessment of V̇o2max in people with cystic fibrosis: a retrospective analysis

The validity and safety of using supramaximal verification (S_max) to confirm a maximal effort during cardiopulmonary exercise testing (CPET) in people with cystic fibrosis (CF) and/or those with severe disease has been questioned. Therefore, this study aimed to investigate these concerns in children, adolescents, and adults with mild-to-severe CF lung disease. Retrospective analysis of 17 pediatric and 28 adult participants with CF [age range: 9.2-62.9 y; forced expiratory volume in 1 s: 66.7% (range: 29.9%-102.3%); 30 men] who completed a routine ramp-incremental cycling test to determine peak oxygen uptake (V̇o_2peak) was studied. Maximal oxygen uptake (V̇o_2max) was subsequently confirmed by S_max at 110% of peak power output. All participants satisfied the criteria to verify a maximal effort during CPET. However, S_max-V̇o_2peak exceeded ramp-V̇o_2peak in 3/14 (21.4%) of pediatric and 6/28 (21.4%) adult exercise tests. A valid measurement of V̇o_2max was attained in 85.7% of pediatric and 96.4% of adult exercise tests, as S_max-V̇o_2peak did not exceed ramp-V̇o_2peak by >9%. Adults ( n = 9) experienced a ≥5% reduction in arterial O₂ saturation during CPET, 4 during both the ramp and S_max, 3 during only the ramp, and 2 during only S_max. S_max did not significantly worsen perceived breathing effort, chest tightness, throat narrowing, or exertion compared with ramp-incremental testing. Given the clinical importance of aerobic fitness in people with CF, incorporating S_max is recommended to provide a safe and valid measure of V̇o_2max in children, adolescents, and adults who span the spectrum of CF disease severity. NEW & NOTEWORTHY Incorporating supramaximal verification into cardiopulmonary exercise testing protocols did not increase the frequency of adverse events or perceived discomfort versus a single-phase incremental exercise test in people with mild-to-severe cystic fibrosis. Furthermore, a valid measure of maximal oxygen uptake (V̇o_2max) was obtained from 85.7% of pediatric and 96.4% of adult exercise tests, whereas peak oxygen uptake underestimated aerobic fitness in comparison with V̇o_2max in 21.4% of cases (by up to 24.4%).

Analysis of oxygen uptake efficiency parameters in young people with cystic fibrosis

PURPOSE

This study characterised oxygen uptake efficiency (OUE) in children with mild-to-moderate cystic fibrosis (CF). Specifically, it investigated (1) the utility of OUE parameters as potential submaximal surrogates of peak oxygen uptake ([Formula: see text]), and (2) the relationship between OUE and disease severity.

METHODS

Cardiopulmonary exercise test (CPET) data were collated from 72 children [36 CF, 36 age- and sex-matched controls (CON)], with OUE assessed as its highest 90-s average (plateau; OUEP), the gas exchange threshold (OUE_GET) and respiratory compensation point (OUE_RCP). Pearson's correlation coefficients, independent t tests and factorial ANOVAs assessed differences between groups and the use of OUE measures as surrogates for [Formula: see text].

RESULTS

A significant (p < 0.05) reduction in allometrically scaled [Formula: see text] and all OUE parameters was found in CF. Significant (p < 0.05) correlations between measurements of OUE and allometrically scaled [Formula: see text], were observed in CF (r = 0.49-0.52) and CON (r = 0.46-0.52). Furthermore, measures of OUE were significantly (p < 0.05) correlated with pulmonary function (FEV_1%predicted) in CF (r = 0.38-0.46), but not CON (r = -0.20-0.14). OUEP was able to differentiate between different aerobic fitness tertiles in CON but not CF.

CONCLUSIONS

OUE parameters were reduced in CF, but were not a suitable surrogate for [Formula: see text]. Clinical teams should, where possible, continue to utilise maximal CPET parameters to measure aerobic fitness in children and adolescents with CF. Future research should assess the prognostic utility of OUEP as it does appear sensitive to disease status and severity.

Exercise testing in cystic fibrosis: Who and why?

Annual review exercise testing is recommended by the Cystic Fibrosis (CF) Trust. Testing to date has focused on evaluating aerobic fitness, a key prognostic indicator. Tests available range from simple field tests, to comprehensive evaluations of aerobic exercise (dys)function - cardiopulmonary exercise testing (CPET). 'Field tests', although easy to perform are limited in the information they provide,whereas CPET, the 'gold standard' measure of aerobic fitness, is recommended as the first-choice exercise test by the European CF Society Exercise Working Group. CPET offers a precise cardiovascular, respiratory and metabolic evaluation of exercise capacity, including assessment of mechanism(s) of exercise limitation.

The oxygen uptake efficiency slope is not a valid surrogate of aerobic fitness in cystic fibrosis

BACKGROUND

Maximal cardiopulmonary exercise testing is recommended on an annual basis for children with cystic fibrosis (CF), due to clinically useful prognostic information provided by maximal oxygen uptake (V̇O_2max ). However, not all patients are able, or willing, to reach V̇O_2max , and therefore submaximal alternatives are required. This study explored the validity of the oxygen uptake efficiency slope (OUES) as a submaximal measure of V̇O_2max in children and adolescents with CF.

METHODS

Data were collated from 72 cardiopulmonary exercise tests (36 CF, 36 controls), with OUES determined relative to maximal and submaximal parameters of exercise intensity, time, and individual metabolic thresholds. Pearson's correlation coefficients, independent t-tests, and factorial ANOVAs were used to determine validity.

RESULTS

Significant (P < 0.05) correlations with V̇O_2max were observed for most expressions of OUES, but were consistently weaker in CF (r = 0.30-0.47) when compared to CON (r = 0.58-0.89). Mean differences for all OUES parameters between groups were not significant (P > 0.05). When split by V̇O_2max tertiles, minimal significant differences were found between, and within, groups for OUES, indicating poor discrimination of V̇O_2max .

CONCLUSIONS

The OUES is not a valid (sub) maximal measure of V̇O_2max in children and adolescents with mild-to-moderate CF. Clinicians should continue to use maximal markers (ie, V̇O_2max ) of exercise capacity.

The Effects of Aerobic and Resistance Exercise on Markers of Large Joint Health in Stable Rheumatoid Arthritis Patients: A Pilot Study

OBJECTIVE

Exercise is beneficial for people with rheumatoid arthritis (RA). However, patients and health professionals have expressed concern about the possible detrimental effects of exercise on joint health. The present study investigated the acute and chronic effects of high-intensity, low-impact aerobic and resistance exercise on markers of large joint health in RA.

METHODS

Eight RA patients and eight healthy, matched control (CTL) participants performed 30 minutes' high-intensity, low-impact aerobic and lower-body resistance exercise, one week apart. Primary outcome measures assessing joint health were serum cartilage oligomeric matrix protein (sCOMP) and knee joint synovial inflammation (Doppler ultrasound colour fraction; CF). These measures were taken at baseline, immediately after and 0.5, one, two, six and 24 hours post-exercise. In a separate study, nine RA patients completed eight weeks of progressive exercise training. The same outcome measures were reassessed at baseline, and at one hour post-exercise of training weeks 0, 1, 4 and 8.

RESULTS

RA patients showed higher overall sCOMP [RA: 1,347 ± 421, CTL: 1,189 ± 562 ng/mL; p < 0.05; effect size (ES) = 0.32] and CF when scanned longitudinally (RA: 0.489 ± 0.30 × 10(-3) , CTL: 0.101 ± 0.13 × 10(-3) ; p < 0.01; ES = 1.73) and transversely (RA: 0.938 ± 0.69 × 10(-3) , CTL: 0.199 ± 0.36 × 10(-3) ; p < 0.01; ES = 1.33) than CTL. However, no acute effects on joint health were observed post-exercise. Similarly, no chronic effects were observed over eight weeks of combined aerobic and resistance training in RA, with positive effects on physical fitness and function.

CONCLUSIONS

RA patients on stable treatment with low disease activity were able to perform an individually prescribed high-intensity, low-impact aerobic and resistance exercise without changes in markers of large joint health. Copyright © 2015 John Wiley & Sons, Ltd.