Pulmonology · Medical Literature
Re: Effects of resistance training with/without photobiomodulation on muscle and respiratory function in difficult-to-control asthma: a randomized trial.
Abstract
This letter discusses Costa et al.'s randomized trial of resistance training (RT) combined with photobiomodulation therapy (PBMT) for difficult-to-control asthma (DTCA). The triple-blind study shows RT+PBMT safely improves peripheral muscle strength and exercise capacity better than RT alone. PBMT has dose-dependent effects, but optimal parameters for chronic respiratory patients remain unclear. Some clinicians have proposed standalone PBMT for DTCA patients unable to complete resistance training, but this approach has not been validated in clinical trials. The absence of a PBMT-only group limits assessment for patients unable to tolerate RT. The intervention did not improve lung function or asthma control, acting only peripherally. RT+PBMT is a useful adjuvant therapy; future studies should optimize PBMT dosing, test standalone PBMT, and examine long-term outcomes, and compare different PBMT wavelengths, energy settings and irradiation sites to refine real-world treatment protocols.
Clinical relevance
In adults with difficult-to-control asthma (DTCA), does the addition of photobiomodulation therapy (PBMT) to a resistance training (RT) program produce superior improvements in peripheral muscle strength, exercise capacity, lung function, and asthma control compared with RT alone? __SNAPSHOT__ {"studyDesign":"Letter to the editor critically appraising a randomized, triple-blind controlled trial (Costa et al., Lasers in Medical Science, PMID 42059974); only the letter abstract is available for this citation","setting":"Not reported in the letter; the underlying RCT (Costa et al.) was conducted in adults with difficult-to-control asthma — institutional setting not reported in the available abstract","sampleSize":"n=30 (as reported for the underlying Costa et al. RCT); group-level allocation not reported in the letter abstract","population":"Adults with difficult-to-control asthma (DTCA); further inclusion/exclusion criteria not reported in the letter abstract","intervention":"Resistance training combined with photobiomodulation therapy (RT+PBMT); LED-based PBMT device as described in the underlying trial","comparator":"Resistance training alone (RT); a PBMT-only (standalone) arm was not included","primaryOutcome":"Peripheral muscle strength and exercise capacity; specific instruments and thresholds not reported in the letter abstract","followUp":"Not reported in the letter abstract","fundingSource":"Not reported"}
Key findings
According to the letter author's characterization of the Costa et al. RCT, RT+PBMT safely produced greater improvements in peripheral muscle strength and exercise capacity compared with RT alone. No quantitative effect sizes, confidence intervals, p-values, or absolute between-group differences are reported in the letter abstract; these values must be sought in the primary Costa et al. publication (PMID 42059974). NNT and NNH cannot be calculated from the available data. Crucially, the combination intervention did not improve lung function or asthma control scores, indicating the observed benefits were confined to peripheral musculoskeletal and exercise capacity domains. The letter notes that PBMT exhibits dose-dependent effects, but no specific dosimetric data or safety event frequencies are presented. No clinically important adverse events attributable to RT+PBMT are described.
Practice implications
The letter establishes that, within the Costa et al. triple-blind RCT, adding PBMT to resistance training appears to confer incremental benefit over RT alone for peripheral muscle strength and exercise capacity in patients with DTCA. However, the intervention did not modify airway physiology: neither lung function parameters nor asthma control scores improved, meaning RT+PBMT should be framed as a peripheral adjuvant strategy, not as a disease-modifying or bronchodilatory treatment. The absence of a PBMT-only arm is a material gap: clinicians who care for DTCA patients unable to tolerate resistance training cannot determine from this trial whether standalone PBMT would be beneficial or safe for that subgroup. The letter also highlights that optimal PBMT dosing parameters (wavelength, energy, irradiation site) for patients with chronic respiratory disease remain undefined. Generalizability is uncertain given the small sample (n=30) and the absence of reported demographic details. Because this summary is based solely on a letter abstract, readers are strongly encouraged to consult the full primary trial (Costa et al., PMID 42059974) before drawing clinical conclusions. __LIMITATIONS__ This citation is a letter to the editor, not the primary trial; no primary data, statistics, or methods are directly verifiable from this abstract alone.,Small sample size (n=30 in the underlying RCT) markedly limits statistical power and precision of effect estimates.,Absence of a PBMT-only arm precludes evaluation of standalone PBMT for patients unable to perform resistance training.,Optimal PBMT dosimetric parameters (wavelength, energy density, irradiation sites, session frequency) for chronic respiratory populations remain unstandardized.,No long-term follow-up data reported; durability of muscle strength and exercise capacity gains is unknown.,Failure to improve lung function or asthma control raises questions about clinical meaningfulness of peripheral gains in this population.,Blinding integrity (triple-blind) is asserted but not independently verifiable from the letter abstract.,Funding source and potential conflicts of interest are not reported, limiting assessment of sponsorship bias.,Generalizability to other asthma phenotypes (e.g., eosinophilic, allergic, corticosteroid-naïve) is not established.,The letter's characterization of the trial findings may introduce a layer of interpretive bias not present in the primary publication. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ RT+PBMT appears to offer incremental improvements in peripheral muscle strength and exercise capacity over RT alone in difficult-to-control asthma, but does not improve lung function or asthma control, limiting its role to a peripheral adjuvant. Given the very small sample, absence of a PBMT-only arm, unresolved dosimetric questions, and lack of long-term outcome data, this combination cannot yet be recommended as standard-of-care adjuvant therapy. Clinicians interested in applying RT+PBMT should await larger trials with optimized dosing protocols and longer follow-up before routine implementation.