# Photobiomodulation Combined with Moderate or High-Intensity Interval Training on Oxygen Consumption and Exercise Tolerance in Patients with Heart Failure

PMID: 41538589
Journal: Arquivos brasileiros de cardiologia
Published: 2025 Nov
Authors: Busin D, Franzoni LT, Turella D, Tairova OS, Silveira ADD, Stein R, Amorim GL, Lago PD, Nunes RB

## Question

Does adding photobiomodulation to moderate continuous or high-intensity interval aerobic training improve VO2peak and exercise tolerance in patients with heart failure?

## Summary

In a nonrandomized heart-failure rehabilitation trial, 10 weeks of aerobic training improved treadmill tolerance measures, especially in the high-intensity interval training group, but adding photobiomodulation did not provide clear additional benefit. One participant did not complete the intervention for personal reasons; formal adverse-event details were not reported.

## Population

- Patients with clinical heart failure referred to a cardiac rehabilitation program.
- Sample size: 49
- Age: 62.73 +/- 10.05 years
- Sex: 67% men (33 of 49)
- Fitness level: Heart-failure rehabilitation population not participating in structured exercise programs.
- Health status: Heart failure with ejection fraction <49%, NYHA II-III, clinically stable at least 3 months, optimized medication, no hospitalizations in prior 6 months.

## Methodology

- Nonrandomized clinical trial with five groups
- 10 weeks
- Cardiac rehabilitation program at CECLIN, University of Caxias do Sul
- Controlled study design.

## Protocol

- HIIT cardiac rehabilitation.
- Modality: Treadmill.
- Work intervals: 4 min at 90%-95% HRR.
- Recovery: 3 min active recovery with light walking.
- Sets or repetitions: 4 intervals.
- Intensity: 90%-95% HRR.
- Session duration: At least 38 min including warm-up; full cooldown not clearly reported.
- Frequency: 3 sessions/week.
- Program length: 10 weeks.
- Progression: Real-time adjustment to maintain target HR zone.
- Moderate continuous training and control comparators.
- Modality: Treadmill or no training.
- Intensity: MCT at 70%-75% HRR; control no rehabilitation intervention.
- Session duration: MCT 47 min.
- Frequency: 3 sessions/week for MCT.
- Program length: 10 weeks.
- Progression: Real-time adjustment to target HRR for training groups.

## Outcomes

### Exercise tolerance
Status: improved
Training groups improved treadmill speed and grade, especially HIIT.

Abstract: time-to-exhaustion performance speed p=0.05 and grade p<0.01.

### VO2peak
Status: mixed
HIIT showed an oxygen-consumption increase in abstract, but full-text group comparisons were not significant.

Abstract HIIT mean difference 1.80 +/- 0.59 mL/kg/min, p=0.002; full text states no significant between-group VO2peak differences.

### PBMT add-on
Status: no clear change
PBMT did not add relevant benefit to training.

Post-hoc comparisons did not reveal significant differences between groups with and without PBMT.

## Practical Insights

- Clinical 4 x 4 HIIT can be delivered with HRR targets in stable HF rehabilitation.
- PBMT should not be assumed to add benefit without better randomized evidence.
- Consumer apps should treat this as clinical-background evidence, not a direct prescription.

## Limitations

- Nonrandomized design
- Small groups
- No sham PBMT group
- No PBMT-only group
- Control group selection bias
- Trial not publicly registered
- Adverse-event reporting unclear

## Safety And Adherence

- Formal adverse events were not reported.
- One participant in the HIIT-PBMT group did not complete the intervention for personal reasons.
- Participants were clinically stable heart-failure patients in a cardiac rehabilitation program with continuous heart-rate monitoring and real-time intensity adjustment.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/41538589/) (pubmed)
- [DOI](https://doi.org/10.36660/abc.20250086) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12711225/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.