Research Appraisals
Evidence-based critical appraisals of the latest medical research, systematically evaluated using Oxford CEBM methodology.
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JMIR formative research
Wearable- and Mobile App-Based Activity Pacing and Fatigue Management in Post-COVID-19 Condition: Exploratory Observational Study
BACKGROUND: Post-COVID-19 fatigue affects millions worldwide; yet, evidence-based management strategies remain limited. Activity pacing, regulating activity to match available energy and minimize symptom exacerbation, may support symptom management, although optimal pacing approaches remain unclear. OBJECTIVE: This study aimed to explore associations between activity pacing strategies delivered through a mobile app and daily fatigue levels in individuals with post-COVID-19 fatigue. METHODS: In this exploratory observational study, 19 adults with post-COVID-19 fatigue used wearable devices (Fitbit Inspire 3) for objective activity monitoring and a mobile app (FatigueSense) to self-report daily symptoms (fatigue and energy levels) and optionally select activity pacing goals (light, balanced, or active) over a period of 3 months. We examined associations between pacing strategies and symptom outcomes by using mixed-effects linear models with random intercepts. Same-day outcomes (fatigue and energy reported on the day of goal selection) were analyzed controlling for age and sex. Next-day outcomes (fatigue and energy reported the day following goal selection) were analyzed controlling for age, sex, and prior-day symptoms. RESULTS: Across 2182 observation days, participants self-selected pacing goals on 816 (37.4%) days, demonstrating symptom-responsive behavior with higher baseline fatigue on pacing days (mean score 1.74, SD 0.59 vs 1.58, SD 0.54 on nonpacing days on a 0-3 scale where 0="none" and 3="severe"; P=.004). On pacing days (584/816, 71.6% with complete data from 18 participants), active pacing was associated with reduced same-day fatigue (β=-0.34, 95% CI -0.49 to -0.19; P<.001) and increased same-day energy (β=8.8, 95% CI 4.7-12.9; P<.001) compared to light pacing. Balanced pacing also showed significant reductions in fatigue (β=-0.15; P=.008) and increases in energy (β=5.8; P<.001) compared to light pacing. Next-day effects were attenuated and nonsignificant (fatigue: β=-0.05, P=.53; energy: β=1.1, P=.61). Individual heterogeneity was substantial, with an intraclass correlation coefficient of 0.32, indicating that 32% of the variance was attributable to between-person differences. Among participants trying multiple strategies, 58.3% (7/12) showed meaningful responses (≥0.3-point fatigue reduction) to structured pacing strategies. CONCLUSIONS: Structured activity pacing strategies (active and balanced) were associated with improved same-day symptom management in individuals with post-COVID-19 fatigue. However, substantial confounding by indication (self-selection of pacing based on symptom state) and individual heterogeneity limit causal interpretation. These exploratory findings warrant testing in randomized controlled trials to establish efficacy and identify responder characteristics.
30 May 2026
Read appraisal →Scientific reports
A randomized controlled trial of adjunctive speleotherapy in asthma, COPD and long COVID
Speleotherapy (underground climate therapy) is a non-pharmacological intervention for chronic respiratory diseases. This randomized controlled trial investigated whether a 3-week speleotherapy course (6 sessions, 2 h/week) improves respiratory outcomes in patients on standard background therapy with asthma, COPD, or Long COVID, and whether it affects blood CO2 levels. The control group did not receive speleotherapy but continued their standard therapy. A total of 208 patients (asthma: n = 107; COPD: n = 59; Long COVID: n = 42) were enrolled across nine centers in Germany, Austria, and Italy. Assessments were conducted pre-intervention (T1), post-intervention (T2), and at 3-month follow-up (T3). Outcome measures included airway inflammation (FeNO), pulmonary function parameters (FVC% predicted values, FEV₁% predicted values, FEV₁/FVC, PEF% predicted values), and respiratory muscle strength (MIP and MEP in absolute values). In addition the following validated questionnaires were administered: Asthma Control Test (ACT), Asthma Quality of Life Questionnaire (AQLQ), COPD Assessment Test (CAT), St. George's Respiratory Questionnaire (SGRQ), Nijmegen Questionnaire (NQ), and Fatigue Assessment Scale (FAS), along with the Long COVID questionnaire from the Median Clinic Group. CO2 levels were assessed via capillary blood (SpCO2) and end-tidal CO2 (PetCO2). Between-group comparisons used the Mann-Whitney U test; within-group changes were assessed with the Wilcoxon signed-rank test (Bonferroni-Holm corrected). In patients with asthma, the predefined primary endpoint (FeNO) showed no significant improvement. In contrast, patient-reported outcomes improved significantly, with clinically relevant gains in asthma control (ACT: p < 0.001) and asthma-related quality of life (total AQLQ: p = 0.005). Lung function parameters showed statistically significant but modest improvements at T2 (FVC: p = 0.011; PEF: p = 0.010; FEV₁ in participants < 70 years: p = 0.035). In patients with COPD, symptom burden improved according to CAT scores (p = 0.036), while no improvements in lung function were observed. Patients with Long COVID reported significant improvements in dysfunctional breathing (NQ: T2: p = 0.014), dyspnea (T2: p = 0.026; T3: p = 0.001), and "problems with stair climbing/muscle exertion" (T2: p = 0.042), as well as improvements in anxiety and sleep-related symptoms (T2: p = 0.021). No improvements in lung function were observed in this group. In the total cohort, the intervention group showed statistically significant improvements compared to controls in respiratory muscle strength (MIP: p = 0.002; MEP: p = 0.018) and dysfunctional breathing (NQ scores at T2: p = 0.007; T3: p = 0.017). In CO₂-rich speleotherapy centers, both SpCO₂ (p = 0.026) and PetCO₂ (p < 0.001) increased at T2. While speleotherapy did not improve FeNO, it was associated with clinically relevant improvements in patient-reported outcomes across disease groups. Changes in lung function and respiratory muscle strength were statistically significant but modest and should be interpreted with caution. Overall, speleotherapy may have direct effects on the airways and breathing regulation, with more consistent evidence for improvements in breathing patterns than for direct effects on the airways.Trial registration: DRKS00033365 (retrospectively registered).
24 May 2026
Read appraisal →Journal of rehabilitation medicine
Effect of inspiratory muscle training on inspiratory muscle strength in adults with post-COVID-19 condition and inspiratory muscle weakness: a randomized controlled trial
OBJECTIVE: Evaluate the effect of inspiratory muscle training in adults with post-COVID-19 condition (PCC) and inspiratory muscle weakness. DESIGN: Randomized controlled trial. SUBJECTS/PATIENTS: Adults with PCC and inspiratory muscle weakness. METHODS: Participants were randomized to inspiratory muscle training twice daily plus individualized exercise twice weekly or exercise alone, with weekly follow-ups over 8 weeks. PRIMARY OUTCOME: inspiratory muscle strength (Maximal Inspiratory Pressure). SECONDARY OUTCOMES: expiratory muscle strength (Maximal Expiratory Pressure); functional capacity (Six‑Minute Walk Test; One‑Minute Sit‑to‑Stand); lung function (spirometry); dyspnoea (mMRC); respiratory symptoms (chest tightness, impaired deep breathing, breathing‑related pain); cough frequency (CAAT cough item); fatigue (Fatigue Severity Scale); physical activity (Frändin-Grimby Activity Scale); activity limitations (Patient‑Specific Functional Scale); and health-related quality of life (EQ‑5D‑5L). Intention-to-treat analyses used imputed missing data. Estimated sample size: 90. RESULTS: Forty-four participants were included (median age 47; 82% women; n = 22/group). Between‑group differences favoured the intervention for inspiratory muscle strength (mean difference: 18%; 95% CI: 5-30; OR for clinically meaningful improvement: 7.08, 95% CI: 1.31-38.32) and cough frequency. No other between-group differences were observed. CONCLUSION: Inspiratory muscle training may improve inspiratory muscle strength and reduce cough frequency, but limited sample size and underrepresentation of the most severely affected warrant cautious interpretation.
23 Apr 2026
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