Effect of Exercise Training on Prognosis in Community-acquired Pneumonia: A Randomized Controlled Trial.

OBJECTIVE: To investigate the effect of standard care (SoC) combined with supervised in-bed cycling (Bed-Cycle) or booklet exercises (Book-Exe) versus SoC in community-acquired pneumonia (CAP). METHODS: In this randomized controlled trial, 186 patients with CAP were assigned to SoC (n = 62), Bed-Cycle (n = 61), or Book-Exe (n = 63). Primary outcome length of stay (LOS) was analyzed with analysis of covariance. Secondary outcomes, 90-day readmission, and 180-day mortality were analyzed with Cox proportional hazard regression and readmission days with negative-binominal regression. RESULTS: LOS was -2% (95% CI: -24 to 25) and -1% (95% CI: -22 to 27) for Bed-Cycle and Book-Exe, compared with SoC. Ninety-day readmission was 35.6% for SoC, 27.6% for Bed-Cycle, and 21.3% for Book-Exe. Adjusted hazard ratio (aHR) for 90-day readmission was 0.63 (95% CI: .33-1.21) and 0.54 (95% CI: .27-1.08) for Bed-Cycle and Book-Exe compared with SoC. aHR for 90-day readmission for combined exercise was 0.59 (95% CI: .33-1.03) compared with SoC. aHR for 180-day mortality was 0.84 (95% CI: .27-2.60) and 0.82 (95% CI: .26-2.55) for Bed-Cycle and Book-Exe compared with SoC. Number of readmission days was 226 for SoC, 161 for Bed-Cycle, and 179 for Book-Exe. Incidence rate ratio for readmission days was 0.73 (95% CI: .48-1.10) and 0.77 (95% CI: .51-1.15) for Bed-Cycle and Book-Exe compared with SoC. CONCLUSIONS: Although supervised exercise training during admission with CAP did not reduce LOS or mortality, this trial suggests its potential to reduce readmission risk and number of readmission days. CLINICAL TRIALS REGISTRATION: NCT04094636.

Exercise adaptations in COPD: the pulmonary perspective.

In chronic obstructive pulmonary disease (COPD), the progressive loss of lung tissue is widely considered irreversible. Thus, various treatment and rehabilitation schemes, including exercise-based pulmonary rehabilitation (PR) are thought to slow down but not reverse or halt the disease. Nonetheless, the adult lung conceals the intrinsic capacity for de novo lung tissue formation in the form of abundant progenitor/stem cell populations. In COPD, these maintain their differentiation potential but appear to be halted by a state of cellular senescence in the mesenchyme, which normally functions to support and coordinate their function. We propose that notably high-intensity interval training may improve pulmonary gas exchange during exercise in patients with COPD by interrupting mesenchymal senescence, thus reestablishing adaptive angiogenesis. By means of this, the downward spiral of dyspnea, poor quality of life, physical inactivity, and early death often observed in COPD may be interrupted. If this is the case, the perception of the regenerative capacity of the lungs will be fundamentally changed, which will warrant future clinical trials on various exercise schemes and other treatments targeting the formation of new lung tissue in COPD.

Body composition, physical capacity, and immuno-metabolic profile in community-acquired pneumonia caused by COVID-19, influenza, and bacteria: a prospective cohort study.

BACKGROUND: Different pathogens can cause community-acquired pneumonia (CAP); however, the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) has re-emphasized the vital role of respiratory viruses as a cause of CAP. The aim was to explore differences in metabolic profile, body composition, physical capacity, and inflammation between patients hospitalized with CAP caused by different etiology. METHODS: A prospective study of Danish patients hospitalized with CAP caused by SARS-CoV-2, influenza, or bacteria. Fat (FM) and fat-free mass (FFM) were assessed with bioelectrical impedance analysis. Physical activity and capacity were assessed using questionnaires and handgrip strength. Plasma (p)-glucose, p-lipids, hemoglobin A1c (HbA1c), p-adiponectin, and cytokines were measured. RESULTS: Among 164 patients with CAP, etiology did not affect admission levels of glucose, HbA1c, adiponectin, or lipids. Overall, 15.2% had known diabetes, 6.1% had undiagnosed diabetes, 51.3% had pre-diabetes, 81% had hyperglycemia, and 60% had low HDL-cholesterol, with no difference between groups. Body mass index, FM, and FFM were similar between groups, with 73% of the patients being characterized with abdominal obesity, although waist circumference was lower in patients with COVID-19. Physical capacity was similar between groups. More than 80% had low handgrip strength and low physical activity levels. Compared to patients with influenza, patients with COVID-19 had increased levels of interferon (IFN)-γ (mean difference (MD) 4.14; 95% CI 1.36-12.58; p = 0.008), interleukin (IL)-4 (MD 1.82; 95% CI 1.12-2.97; p = 0.012), IL-5 (MD 2.22; 95% CI 1.09-4.52; p = 0.024), and IL-6 (MD 2.41; 95% CI 1.02-5.68; p = 0.044) and increased IFN-γ (MD 6.10; 95% CI 2.53-14.71; p < 0.001) and IL-10 (MD 2.68; 95% CI 1.53-4.69; p < 0.001) compared to patients with bacterial CAP, but no difference in IL-1ß, tumor necrosis factor-α, IL-8, IL-18, IL-12p70, C-reactive protein, and adiponectin. CONCLUSION: Despite higher inflammatory response in patients with COVID-19, metabolic profile, body composition, and physical capacity were similar to patients with influenza and bacterial CAP.

The role of lactate in sepsis and COVID-19: Perspective from contracting skeletal muscle metabolism.

NEW FINDINGS: What is the topic of this review? Lactate is considered an important substrate for mitochondria in the muscles, heart and brain during exercise and is the main gluconeogenetic precursor in the liver and kidneys. In this light, we review the (patho)physiology of lactate metabolism in sepsis and coronavirus disease 2019 (COVID-19). What advances does it highlight? Elevated blood lactate is strongly associated with mortality in septic patients. Lactate seems unrelated to tissue hypoxia but is likely to reflect mitochondrial dysfunction and high adrenergic stimulation. Patients with severe COVID-19 exhibit near-normal blood lactate, indicating preserved mitochondrial function, despite a systemic hyperinflammatory state similar to sepsis. ABSTRACT: In critically ill patients, elevated plasma lactate is often interpreted as a sign of organ hypoperfusion and/or tissue hypoxia. This view on lactate is likely to have been influenced by the pioneering exercise physiologists around 1920. August Krogh identified an oxygen deficit at the onset of exercise that was later related to an oxygen 'debt' and lactate accumulation by A. V. Hill. Lactate is considered to be the main gluconeogenetic precursor in the liver and kidneys during submaximal exercise, but hepatic elimination is attenuated by splanchnic vasoconstriction during high-intensity exercise, causing an exponential increase in blood lactate. With the development of stable isotope tracers, lactate has become established as an important energy source for muscle, brain and heart tissue, where it is used for mitochondrial respiration. Plasma lactate > 4 mM is strongly associated with mortality in septic shock, with no direct link between lactate release and tissue hypoxia. Herein, we provide evidence for mitochondrial dysfunction and adrenergic stimulation as explanations for the sepsis-induced hyperlactataemia. Despite profound hypoxaemia and intense work of breathing, patients with severe coronavirus disease 2019 (COVID-19) rarely exhibit hyperlactataemia (> 2.5 mM), while presenting a systemic hyperinflammatory state much like sepsis. However, lactate dehydrogenase, which controls the formation of lactate, is markedly elevated in plasma and strongly associated with mortality in severe COVID-19. We briefly review the potential mechanisms of the lactate dehydrogenase elevation in COVID-19 and its relationship to lactate metabolism based on mechanisms established in contracting skeletal muscle and the acute respiratory distress syndrome.

Effect of 6 wk of high-intensity one-legged cycling on functional sympatholysis and ATP signaling in patients with heart failure.

Breathlessness during daily activities is the primary symptom in patients with heart failure (HF). Poor correlation between the hemodynamic parameters of left ventricular performance and perceived symptoms suggests that other factors, such as skeletal muscle function, play a role in determining exercise capacity. We investigated the effect of 6 wk of high-intensity, one-legged cycling (HIC; 8 × 4 at 90% one-legged cycling max) on 1) the ability to override sympathetic vasoconstriction (arterial infusion of tyramine) during one-legged knee-extensor exercise (KEE), 2) vascular function (arterial infusion of ACh, sodium nitroprusside, tyramine, and ATP), and 3) exercise capacity in HF patients with reduced ejection fraction ( n = 8) compared with healthy individuals ( n = 6). Arterial tyramine infusion lowered leg blood flow and leg vascular conductance at rest and during KEE before the training intervention in both groups ( P < 0.05) but not during KEE after the training intervention. There was no difference between groups. The peak vasodilatory response to ATP was blunted in HF patients ( P < 0.05), whereas there was no difference in ACh- and sodium nitroprusside-induced vasodilation between HF patients and healthy individuals. ACh-induced vasodilation increased in HF patients after the training intervention ( P < 0.05). HIC improved aerobic capacity in both groups ( P < 0.05), whereas only HF patients made improvements in the 6-min walking distance ( P < 0.05). These results suggest that exercise hyperemia and functional sympatholysis are not altered in HF patients and that functional sympatholysis is improved with HIC in both HF patients and healthy individuals. Moreover, these results suggest that the peak vasodilatory response to ATP is blunted in HF. NEW & NOTEWORTHY The ability to override sympathetic vasoconstrictor activity (by arterial tyramine infusion) during exercise is not different between heart failure patients and healthy individuals and is improved by high-intensity, one-legged cycling training. The peak vasodilatory response to ATP is reduced in heart failure patients.

Lower mortality after early supervised pulmonary rehabilitation following COPD-exacerbations: a systematic review and meta-analysis.

BACKGROUND: Pulmonary rehabilitation (PR), delivered as a supervised multidisciplinary program including exercise training, is one of the cornerstones in the chronic obstructive pulmonary disease (COPD) management. We performed a systematic review and meta-analysis to assess the effect on mortality of a supervised early PR program, initiated during or within 4 weeks after hospitalization with an acute exacerbation of COPD compared with usual post-exacerbation care or no PR program. Secondary outcomes were days in hospital, COPD related readmissions, health-related quality of life (HRQoL), exercise capacity (walking distance), activities of daily living (ADL), fall risk and drop-out rate. METHODS: We identified randomized trials through a systematic search using MEDLINE, EMBASE and Cocharne Library and other sources through October 2017. Risk of bias was assessed regarding randomization, allocation sequence concealment, blinding, incomplete outcome data, selective outcome reporting, and other biases using the Cochrane Risk of Bias tool. RESULTS: We included 13 randomized trials (801 participants). Our meta-analyses showed a clinically relevant reduction in mortality after early PR (4 trials, 319 patients; RR = 0.58 (95% CI: [0.35 to 0.98])) and at the longest follow-up (3 trials, 127 patients; RR = 0.55 (95% CI: [0.12 to 2.57])). Early PR reduced number of days in hospital by 4.27 days (1 trial, 180 patients; 95% CI: [- 6.85 to - 1.69]) and hospital readmissions (6 trials, 319 patients; RR = 0.47 (95% CI: [0.29 to 0.75])). Moreover, early PR improved HRQoL and walking distance, and did not affect drop-out rate. Several of the trials had unclear risk of bias in regard to the randomization and blinding, for some outcome there was also a lack of power. CONCLUSION: Moderate quality of evidence showed reductions in mortality, number of days in hospital and number of readmissions after early PR in patients hospitalized with a COPD exacerbation. Long-term effects on mortality were not statistically significant, but improvements in HRQoL and exercise capacity appeared to be maintained for at least 12 months. Therefore, we recommend early supervised PR to patients with COPD-related exacerbations. PR should be initiated during hospital admission or within 4 weeks after hospital discharge.

Corrigendum: Adiponectin as a predictor of mortality and readmission in patients with community-acquired pneumonia: a prospective cohort study.

[This corrects the article DOI: 10.3389/fmed.2024.1329417.].

Adiponectin as a predictor of mortality and readmission in patients with community-acquired pneumonia: a prospective cohort study.

Background: Adiponectin is secreted by adipocytes and is inversely associated with obesity. Given the association between low body mass index (BMI) and higher mortality risk after community-acquired pneumonia (CAP), we hypothesized that high adiponectin levels are associated with a higher risk of adverse clinical outcomes in patients with CAP. Methods: In a prospective cohort study of 502 patients hospitalized with CAP, adiponectin was measured in serum at admission. The associations between adiponectin and clinical outcomes were estimated with logistic regression analyses adjusted for age, sex, and measures of obesity (BMI, waist circumference or body fat percentage). Results: Adiponectin was associated with higher 90-day mortality for each 1 µg/mL increase [OR 1.02, 95% CI (1.00, 1.04), p = 0.048] independent of age and sex. Likewise, adiponectin was associated with a higher risk of 90-day readmission for each 1 µg/mL increase [OR 1.02, 95% CI (1.01, 1.04), p = 0.007] independent of age and sex. The association between adiponectin and 90-day mortality disappeared, while the association with 90-day readmission remained after adjusting for adiposity. Conclusion: Adiponectin was positively associated with mortality and readmission. The association with mortality depended on low body fat, whereas the association with readmission risk was independent of obesity.

Inflammatory and endothelial host responses in community-acquired pneumonia: exploring the relationships with HbA1c, admission plasma glucose, and glycaemic gap-a cross-sectional study.

Introduction: Diabetes is associated with dysregulated immune function and impaired cytokine release, while transient acute hyperglycaemia has been shown to enhance inflammatory cytokine release in preclinical studies. Although diabetes and acute hyperglycaemia are common among patients with community-acquired pneumonia (CAP), the impact of chronic, acute, and acute-on-chronic hyperglycaemia on the host response within this population remains poorly understood. This study investigated whether chronic, acute, and acute-on- chronic hyperglycaemia are associated with distinct mediators of inflammatory, endothelial, and angiogenic host response pathways in patients with CAP. Methods: In a cross-sectional study of 555 patients with CAP, HbA1c, admission plasma (p)-glucose, and the glycaemic gap (admission p-glucose minus HbA1c- derived average p-glucose) were employed as measures of chronic, acute, and acute-on-chronic hyperglycaemia, respectively. Linear regression was used to model the associations between the hyperglycaemia measures and 47 proteins involved in inflammation, endothelial activation, and angiogenesis measured at admission. The models were adjusted for age, sex, CAP severity, pathogen, immunosuppression, comorbidity, and body mass index. Adjustments for multiple testing were performed with a false discovery rate threshold of less than 0.05. Results: The analyses showed that HbA1c levels were positively associated with IL-8, IL-15, IL-17A/F, IL-1RA, sFlt-1, and VEGF-C. Admission plasma glucose was also positively associated with these proteins and GM-CSF. The glycaemic gap was positively associated with IL-8, IL-15, IL-17A/F, IL-2, and VEGF-C. Conclusion: In conclusion, chronic, acute, and acute-on-chronic hyperglycaemia were positively associated with similar host response mediators. Furthermore, acute and acute-on-chronic hyperglycaemia had unique associations with the inflammatory pathways involving GM-CSF and IL-2, respectively.

Pituitary-gonadal hormones associated with respiratory failure in men and women hospitalized with COVID-19: an observational cohort study.

Aim: To explore pituitary-gonadal hormone concentrations and assess their association with inflammation, severe respiratory failure, and mortality in hospitalized men and women with COVID-19, and compare these to hormone concentrations in hospitalized patients with bacterial community-acquired pneumonia (CAP) and influenza virus CAP and to concentrations in a reference group of healthy individuals. Methods: Serum concentrations of testosterone, estrone sulfate, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and interleukin-6 (IL-6) were measured within 4 days of admission. Associations were assessed by logistic regression analysis in patients with COVID-19, and results were reported as odds ratio with 95% CI per two-fold reduction after adjustment for age, comorbidities, days to sample collection, and IL-6 concentrations. Results: In total, 278 patients with COVID-19, 21 with influenza virus CAP, and 76 with bacterial CAP were included. Testosterone concentrations were suppressed in men hospitalized with COVID-19, bacterial and influenza virus CAP, and moderately suppressed in women. Reductions in testosterone (OR: 3.43 (1.14-10.30), P = 0.028) and LH (OR: 2.51 (1.28-4.92), P = 0.008) were associated with higher odds of mehanical ventilation (MV) in men with COVID-19. In women with COVID-19, reductions in LH (OR: 3.34 (1.02-10-90), P = 0.046) and FSH (OR: 2.52 (1.01-6.27), P = 0.047) were associated with higher odds of MV. Conclusion: Low testosterone and LH concentrations were predictive of severe respiratory failure in men with COVID-19, whereas low concentrations of LH and FSH were predictive of severe respiratory failure in women with COVID-19.

Diabetes Status, c-Reactive Protein, and Insulin Resistance in Community-Acquired Pneumonia-A Prospective Cohort Study.

C-reactive protein (CRP) is commonly used to guide community-acquired pneumonia (CAP) treatment. A positive association between admission glucose and CRP levels has been observed in patients with CAP. The associations between prediabetes, unknown diabetes, acute-on-chronic hyperglycaemia, and CRP levels, and between admission CRP levels and insulin resistance (IR) in CAP, remain unexplored. This study investigated the associations firstly between chronic, acute, and acute-on-chronic hyperglycaemia and CRP levels, and secondly between admission CRP levels and IR in CAP. In a prospective cohort study of adults with CAP, the associations between chronic, acute, and acute-on-chronic hyperglycaemia (admission glucose minus HbA1c-derived average glucose) and CRP levels until admission day 3 were modelled with repeated-measures linear mixed models. IR was estimated with the homeostasis model assessment of IR (HOMA-IR). The association between admission CRP levels and HOMA-IR was modelled with linear regression. In 540 patients, no association between chronic, acute, or acute-on-chronic hyperglycaemia and CRP levels was found. In 266 patients, every 50 mg/L increase in admission CRP was associated with a 7% (95% CI 1-14%) higher HOMA-IR. In conclusion, our findings imply that hyperglycaemia does not influence CRP levels in patients with CAP, although admission CRP levels were positively associated with IR.

Physical Inactivity and Sedentarism during and after Admission with Community-Acquired Pneumonia and the Risk of Readmission and Mortality: A Prospective Cohort Study.

BACKGROUND: Bed rest with limited physical activity is common during admission. The aim was to determine the association between daily step count and physical activity levels during and after admission with community-acquired pneumonia (CAP) and the risk of readmission and mortality. METHODS: A prospective cohort study of 166 patients admitted with CAP. Step count and physical activity were assessed with accelerometers during and after admission and were categorised as sedentary, light, or moderate-vigorous physical activity. Linear regression was used to assess the association between step count and length of stay. Logistic regression was used to assess the association between step count, physical activity level, and risk of readmission and mortality. RESULTS: Patients admitted with CAP were sedentary, light physically active, and moderate-to-vigorous physically active 96.4%, 2.6%, and 0.9% of their time, respectively, with 1356 steps/d. For every 500-step increase in daily step count on day 1, the length of stay was reduced by 6.6%. For every 500-step increase in daily step count during admission, in-hospital and 30-day mortality was reduced. Increased light and moderate-to-vigorous physical activity during admission were associated with reduced risk of in-hospital and 30-day mortality. After discharge, patients increased their daily step count to 2654 steps/d and spent more time performing light and moderate-to-vigorous physical activity. For every 500-step increase in daily step count after discharge, the risk of readmission was reduced. Higher moderate-to-vigorous physical activity after discharge was associated with a reduced risk of readmission. CONCLUSIONS: Increased physical activity during admission was associated with a reduced length of stay and risk of mortality, whereas increased physical activity after discharge was associated with a reduced risk of readmission in patients with CAP. Interventions focusing on increasing physical activity levels should be prioritised to improve the prognosis of patients admitted with CAP.

Association between Barthel Index, Grip Strength, and Physical Activity Level at Admission and Prognosis in Community-Acquired Pneumonia: A Prospective Cohort Study.

Background: Impaired functional status is a risk factor for hospitalization in patients with community-acquired pneumonia (CAP). The aim was to determine the influence of functional status and physical activity level on severe outcomes, including length of stay, admission to the intensive care unit (ICU), readmission, and mortality in patients with CAP. Methods: A prospective cohort study among patients hospitalized with CAP. Functional status was assessed with the Barthel index and grip strength, and physical activity level was assessed using the international physical activity questionnaire. Linear regression was used to assess the association with length of stay, and logistic regression was used to assess the risk of severe outcomes. Results: Among 355 patients admitted with CAP, 18% had a low Barthel index (<80), 45% had a low grip strength, and 75% had a low physical activity level. Low Barthel index was associated with increased risk of ICU admission (OR 3.6, 95% CI 1.2−10.9), longer length of stay (27.9%, 95% CI 2.3−59.7%), readmission within 30, 90, and 180 days (OR 2.1−2.4, p < 0.05), and mortality within 90 and 180 days (OR 4.2−5.0, p < 0.05). Low grip strength was associated with increased risk of 90 days readmission (OR 1.6, 95% CI 1.0−2.6, p < 0.05) and mortality within 30, 90, and 180 days (OR 2.6−3.2, p < 0.05). Low physical activity level was associated with increased risk of readmission within 90 and 180 days (OR 1.8−2.1, p < 0.05) and mortality within 30, 90, and 180 days (OR 3.3−5.5, p < 0.05). Conclusions: Impaired functional status and low physical activity level were associated with a longer length of stay and increased risk of ICU admission, readmission, and mortality in patients hospitalized with CAP. Routine assessment of functional status and physical activity level in clinical care could enable early identification of individuals with excess risk for a poor prognosis. Trial registration: ClinicalTrials.gov, NCT03795662.

Biomarkers for iron metabolism among patients hospitalized with community-acquired pneumonia caused by infection with SARS-CoV-2, bacteria, and influenza.

Ferritin, the central iron storage protein, has attracted attention as a biomarker of severe COVID-19. Few studies have investigated regulators of iron metabolism in the context of COVID-19. The aim was to evaluate biomarkers for iron metabolism in the acute phase response to community-acquired pneumonia (CAP) caused by SARS-CoV-2 compared with CAP caused by bacteria or influenza virus in hospitalized patients. A cross-sectional study of 164 patients from the Surviving Pneumonia Cohort recruited between January 8, 2019 and May 26, 2020. Blood samples were collected at admission and analyzed for levels of C-reactive protein (CRP), ferritin, soluble transferrin receptor, erythroferrone, and hepcidin. Median (IQR) hepcidin was higher in SARS-CoV-2 with 143.8 (100.7-180.7) ng/mL compared with bacterial and influenza infection with 78.8 (40.1-125.4) and 53.5 (25.2-125.8) ng/mL, respectively. The median ferritin level was more than 2-fold higher in patients with SARS-CoV-2 compared with the other etiologies (p < 0.001). Patients with SARS-CoV-2 had lower levels of erythroferrone and CRP compared with those infected with bacteria. Higher levels of hepcidin and lower levels of erythroferrone despite lower CRP levels among patients with SARS-CoV-2 compared with those infected with bacteria indicate alterations in iron metabolism in patients with SARS-CoV-2 infection.

Are Undernutrition and Obesity Associated with Post-Discharge Mortality and Re-Hospitalization after Hospitalization with Community-Acquired Pneumonia?

Undernutrition is associated with increased mortality after hospitalization with community-acquired pneumonia (CAP), whereas obesity is associated with decreased mortality in most studies. We aimed to determine whether undernutrition and obesity are associated with increased risk of re-hospitalization and post-discharge mortality after hospitalization. This study was nested within the Surviving Pneumonia cohort, which is a prospective cohort of adults hospitalized with CAP. Patients were categorized as undernourished, well-nourished, overweight, or obese. Undernutrition was based on diagnostic criteria by the European Society for Clinical Nutrition and Metabolism. Risk of mortality was investigated using multivariate logistic regression and re-hospitalization with competing risk Cox regression where death was the competing event. Compared to well-nourished patients, undernourished patients had a higher risk of 90-day (OR 3.0, 95% CI 1.0; 21.4) mortality, but a similar 30-day and 180-day mortality risk. Obese patients had a similar re-hospitalization and mortality risk as well-nourished patients. In conclusion, among patients with CAP, undernutrition was associated with increased risk of mortality. Undernourished patients are high-risk patients, and our results indicate that in-hospital screening of undernutrition should be implemented to identify patients at mortality risk. Studies are required to investigate whether nutritional therapy after hospitalization with CAP would improve survival.

Regulation of the microvasculature during small muscle mass exercise in chronic obstructive pulmonary disease vs. chronic heart failure.

Aim: Skeletal muscle convective and diffusive oxygen (O2) transport are peripheral determinants of exercise capacity in both patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). We hypothesised that differences in these peripheral determinants of performance between COPD and CHF patients are revealed during small muscle mass exercise, where the cardiorespiratory limitations to exercise are diminished. Methods: Eight patients with moderate to severe COPD, eight patients with CHF (NYHA II), and eight age- and sex-matched controls were studied. We measured leg blood flow (Q̇leg) by Doppler ultrasound during submaximal one-legged knee-extensor exercise (KEE), while sampling arterio-venous variables across the leg. The capillary oxyhaemoglobin dissociation curve was reconstructed from paired femoral arterial-venous oxygen tensions and saturations, which enabled the estimation of O2 parameters at the microvascular level within skeletal muscle, so that skeletal muscle oxygen conductance (DSMO2) could be calculated and adjusted for flow (DSMO2/Q̇leg) to distinguish convective from diffusive oxygen transport. Results: During KEE, Q̇leg increased to a similar extent in CHF (2.0 (0.4) L/min) and controls (2.3 (0.3) L/min), but less in COPD patients (1.8 (0.3) L/min) (p <0.03). There was no difference in resting DSMO2 between COPD and CHF and when adjusting for flow, the DSMO2 was higher in both groups compared to controls (COPD: 0.97 (0.23) vs. controls 0.63 (0.24) mM/kPa, p= 0.02; CHF 0.98 (0.11) mM/kPa vs. controls, p= 0.001). The Q̇-adjusted DSMO2 was not different in COPD and CHF during KEE (COPD: 1.19 (0.11) vs. CHF: 1.00 (0.18) mM/kPa; p= 0.24) but higher in COPD vs. controls: 0.87 (0.28) mM/kPa (p= 0.02), and only CHF did not increase Q̇-adjusted DSMO2 from rest (p= 0.2). Conclusion: Disease-specific factors may play a role in peripheral exercise limitation in patients with COPD compared with CHF. Thus, low convective O2 transport to contracting muscle seemed to predominate in COPD, whereas muscle diffusive O2 transport was unresponsive in CHF.

Risk factors for fatigue and impaired function eight months after hospital admission with COVID-19.

INTRODUCTION: We aimed to evaluate post-COVID-19 fatigue, change in functional capacity and health-related quality of life (HRQoL) eight months after discharge from hospital due to COVID-19. METHODS: A total of 83 patients (35 women) admitted to the Copenhagen University Hospital - North Zealand Hospital, Denmark, for COVID-19 during the period from March to June 2020 were evaluated eight months after discharge using validated questionnaires quantifying fatigue, HRQoL and post-COVID-19 functional status. Follow-up data were correlated with measures of pre-COVID-19 status (anthropometrics, comorbidities) and measures of severity of the acute infection. RESULTS: A total of 22 (65%) women and 12 (26%) men reported excessive fatigue. In all, 20 women (67%) and 17 men (37%) reported decreased physical function. Female sex was associated with fatigue. Loss of physical function was associated with pre-COVID-19 presence of heart disease and absence of lung disease. Severity of the acute COVID-19 infection was not associated with fatigue or change in functional status. Fatigue and functional status were correlated with both generic HRQoL and lung disease-specific HRQoL. CONCLUSIONS: Female sex was associated with a higher risk of fatigue eight months after hospitalisation with COVID-19 infection. Regarding loss of functional capacity after COVID-19, we found an apparently protective effect of pre-COVID-19 lung disease. Our findings underscore the urgent need for further research and the importance of evaluating those recovering from COVID-19 for symptoms of excessive fatigue and change in functional capacity irrespective of the severity of the initial infection. FUNDING: none. TRIAL REGISTRATION: not relevant.

Cardiorespiratory responses to high-intensity skeletal muscle metaboreflex activation in chronic obstructive pulmonary disease.

BACKGROUND: Augmented skeletal muscle metaboreflex activation may accompany chronic obstructive pulmonary disease (COPD). The maintained metaboreflex control of mean arterial pressure (MAP) that has been reported may reflect limited evaluation using only one moderate bout of static handgrip (HG) and following postexercise ischaemia (PEI). OBJECTIVE: We tested the hypothesis that cardiovascular and respiratory responses to high-intensity static HG and isolated metaboreflex activation during PEI are augmented in COPD patients. METHODS: Ten patients with moderate to severe COPD and eight healthy age- and BMI-matched controls performed two-minute static HG at moderate (30% maximal voluntary contraction; MVC) and high (40% MVC) intensity followed by PEI. RESULTS: Despite similar ratings of perceived exertion, arm muscle mass and strength, COPD patients demonstrated lower MAP responses during both HG intensities compared with controls (time × group interaction, p < .05). Indeed, during high-intensity HG at 40% MVC, peak MAP responses were significantly lower in COPD patients (ΔMAP: COPD 41 ± 9 mmHg vs. controls 56 ± 14 mmHg, p < .05). Notably, no group differences in MAP were observed during PEI (e.g. 40% MVC PEI: ΔMAP COPD 33 ± 9 mmHg vs. controls 33 ± 6 mmHg, p > .05). We found no between-group differences in heart rate, respiratory rate, or estimated minute ventilation during HG or PEI. CONCLUSION: These results suggest that the pressor response to high-intensity HG is blunted in COPD patients. Moreover, despite inducing a strong cardiovascular and respiratory stimulus, skeletal muscle metaboreflex activation evoked similar responses in COPD patients and controls.

The impact of physical training on length of hospital stay and physical function in patients hospitalized with community-acquired pneumonia: protocol for a randomized controlled trial.

BACKGROUND: Community-acquired pneumonia (CAP) is a leading cause of hospitalization worldwide. Bed rest with low levels of physical activity is common during periods of hospitalization and leads to functional decline as well as increased risk of complications. The aim of this study is to assess the effect of supervised physical training during hospitalization with CAP compared with standard usual care for CAP on length of hospital stay, risk of readmission, mortality risk, physical capacity, muscle and fat mass, muscle strength, metabolic function, systemic inflammation, health-related quality of life, and physical activity level. METHODS: This study is a randomized controlled trial with three parallel experimental arms. Based on a sample size calculation, a total of 210 patients admitted with CAP at Nordsjællands Hospital, Hillerød, Denmark, will be recruited. Patients will be randomly allocated (1:1:1) to either (1) standard usual care, (2) standard usual care combined with in-bed cycling, or (3) standard usual care combined with exercises from a booklet. The primary outcome is differences in length of hospital stay between groups, with secondary outcomes being differences between groups in time to (1) 90-day readmission and (2) 180-day mortality. Further secondary outcomes are differences in changes from baseline between groups in (3) lean mass, (4) fat mass, (5) fat-free mass, (6) physical capacity, (7) health-related quality of life, (8) systemic inflammation, and (9) physical activity level after discharge. Data on length of hospital stay, readmission, and mortality will be collected from patient files, while total lean, fat, and fat-free mass will be quantitated by dual-energy x-ray absorptiometry and bioelectrical impedance analysis. Physical function will be assessed using grip strength, 30-s chair stand tests, and Barthel Index-100. Health-related quality of life will be assessed with the EQ-5D-5L questionnaire. Systemic inflammation will be assessed in blood samples, while accelerometers are used for measuring physical activity. DISCUSSION: If a simple physical training program appears to diminish the impact of critical illness and hospitalization on clinical outcome, mobility, and health-related quality of life, it may lead to novel therapeutic approaches in the treatment of patients hospitalized with CAP. TRIAL REGISTRATION: ClinicalTrials.gov NCT04094636 . Registered on 1 April 2019.