Photobiomodulation Therapy with Cardiac Rehabilitation in HFrEF/HFmrEF: Promise, Parameters, and the Primacy of Exercise

Exercise intolerance in heart failure (HF) is not solely a central pump problem. Peripheral mechanisms, such as impaired skeletal-muscle oxygen extraction and mitochondrial dysfunction, are major limiting factors and correlate with early fatigue and poorer outcomes. On this basis, low-level light/laser photobiomodulation therapy (PBMT) has attracted interest as an adjunct to rehabilitation: by targeting cytochrome-c oxidase, PBMT may boost mitochondrial ATP generation, modulate redox signaling, and enhance microvascular perfusion.

In this edition, the article by Busin et al. evaluates whether the addition of PBMT to either continuous moderate-intensity training (CMT) or high-intensity interval training (HIIT) augments gains in peak oxygen uptake (VO₂peak) and other CPET indices among symptomatic, clinically stable HFrEF/HFmrEF patients. In a non-randomized, five-arm design (CMT, HIIT, CMT+PBMT, HIIT+PBMT, and a control group) with 49 participants, the authors observed significant improvements in exercise tolerance across all intervention groups, but no additional benefit from PBMT on VO₂peak, ventilatory efficiency (VE/VCO₂ slope), or oxygen uptake efficiency slope (OUES). Numerical trends favored some PBMT arms, yet between-group differences were not statistically significant. The HIIT arms performed particularly well, but PBMT (applied only before sessions and at a modest dose) did not yield additional improvements.

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