High-intensity interval training versus progressive high-intensity circuit resistance training on endothelial function and cardiorespiratory fitness in heart failure: A preliminary randomized controlled trial
Question
Do high-intensity interval training and progressive high-intensity circuit resistance training improve endothelial function and cardiorespiratory fitness, and secondarily muscle strength and physical performance, in stable heart failure patients?
Summary
In a small preliminary randomized trial of stable heart failure patients, 36 supervised sessions of aerobic HIIT and progressive high-intensity circuit resistance training improved cardiorespiratory fitness versus control, but neither training mode improved brachial artery flow-mediated dilation. HIIT showed broader improvements in cycling peak power, isokinetic strength-related measures, and global physical performance, while CRT improved chair-stand time. No medical complications occurred during training.
Methodology
- Stable heart failure patients on optimal medical therapy, including reduced, mid-range, and preserved ejection fraction classifications.
- 23 participants.
- Treadmill and cycle ergometer alternated by session.
- Work intervals: 3 minutes high intensity.
- Recovery: 4 minutes moderate intensity.
- Intensity: High intensity based on CPET-derived HR zones: above the moderate upper limit by up to 10%; moderate intensity around VT1.
- Approximately 50 minutes, including 10 minutes moderate aerobic work before 28-minute HIIT block.
- 3 sessions/week.
- 36 sessions.
- Preliminary longitudinal parallel randomized controlled trial with three groups: HIIT, circuit-resistance training, and control.
- Flow-mediated dilation, Peak oxygen uptake, METs max, and Isokinetic muscle strength were tracked.
Outcomes
Endothelial function
Neither HIIT nor CRT improved FMD compared with baseline or control.
FMD change: HIIT -0.36 (95% CI -5.05 to 4.33), CRT +0.42 (-3.86 to 4.70), control +0.90 (-4.35 to 6.14); between-group differences not significant.
VO2 peak
VO2 peak improved within both HIIT and CRT, while control did not improve.
HIIT +2.2 mL/kg/min (95% CI 0.2 to 4.1), CRT +3.1 (0.8 to 5.3), control -0.1 (-2.0 to 1.9); abstract reports time*group p<0.05.
Cycling peak power and strength
HIIT improved cycling peak power output and several strength-related measures; CRT had smaller or nonsignificant strength changes.
HIIT cycling peak power +18.1 W (95% CI 4.4 to 31.9); HIIT isokinetic torque peak/body weight +12.1% (1.8 to 22.4); average power +20.8 W (4.7 to 36.8).
Physical performance
CRT improved chair-stand completion time, and HIIT improved global physical performance according to authors.
CRT chair stand seconds -3.3 (95% CI -6.5 to -0.2); total SPPB time/group result p=0.008.
Safety
No medical complications were reported during supervised training sessions.
Insights
- In stable HF, high-intensity interval work can be feasible when medically screened, monitored, and supervised.
- A familiarization period may be important before requiring target high-intensity intervals in clinical populations.
- Fitness benefits should not be assumed to imply vascular endothelial benefits.
Limitations
- Preliminary small trial stopped early because of COVID-19.
- Missing outcome data for FMD, SPPB, and muscle strength.
- Only one center provided data despite multicenter adaptation.
- Results are not directly generalizable to unsupervised consumer HIIT or unstable HF.
Safety
- No medical complications occurred during training sessions.
- Physiotherapists monitored BP, HR, RPE, excessive tiredness, sweating, paleness, palpitations, and chest pain.
- A cardiologist was available in case of health concerns.