High-Intensity Interval Training is Safe, Feasible and Efficacious in Nonalcoholic Steatohepatitis: A Randomized Controlled Trial
Question
Is 12 weeks of supervised HIIT safe, feasible, and efficacious for improving aerobic fitness and peripheral insulin sensitivity in adults with biopsy-proven NASH compared with a sham-exercise control?
Summary
In adults with biopsy-confirmed nonalcoholic steatohepatitis, 12 weeks of supervised 4 x 4 min HIIT produced no HIIT-related adverse events and met the authors' feasibility criteria among completers. Compared with a supervised stretching control, HIIT improved exercise capacity and peripheral insulin sensitivity, with favorable effect-size signals for BMI, waist circumference, abdominal fat, intrahepatic lipid, total cholesterol, and symptom-related quality of life. The study was very small and affected by COVID-era recruitment limits.
Methodology
- Adults with biopsy-proven nonalcoholic steatohepatitis.
- 14 participants.
- Treadmill running/walking preferred, with cycle/row/arm ergometer alternatives.
- Work intervals: 4 min at 85-95% HRmax.
- Recovery: 3 min at about 60% HRmax.
- Intensity: 85-95% HRmax and RPE around 15-19/20 during intervals.
- About 38 min.
- 3 sessions/week.
- 12 weeks.
- Prospectively registered randomized controlled trial comparing supervised HIIT with supervised stretching control.
- Safety and feasibility, Exercise capacity, Peripheral insulin sensitivity, and Liver and body composition outcomes were tracked.
Outcomes
Safety and feasibility
No HIIT-related adverse events occurred and HIIT met feasibility criteria among completers.
Program completion 75%; session adherence among completers 95.4 +/- 7.3%; intensity adherence 95.3 +/- 6.0%; duration adherence 96.8 +/- 2.4%.
Exercise capacity
HIIT improved exercise capacity versus stretching control.
Adjusted mean difference 134.2 s (95% CI 19.8 to 248.6), eta2=0.44, p=0.03.
Peripheral insulin sensitivity
Clamp-measured peripheral insulin sensitivity improved in HIIT and worsened in control.
Adjusted mean difference 3.4 mg/kgLegFFM/min (95% CI 0.9 to 6.8), eta2=0.32, p=0.046.
VO2peak
VO2peak did not improve versus control.
Adjusted mean difference -0.4 mL/kg/min, p=0.71.
Cardiometabolic and liver secondary outcomes
Effect sizes favored HIIT for BMI, waist circumference, abdominal adipose tissue, intrahepatic lipid, total cholesterol, and metabolic syndrome severity, but many were not statistically significant in this small trial.
Total cholesterol adjusted mean difference -0.8 mmol/L (95% CI -1.3 to -0.3), p=0.004; intrahepatic lipid p=0.08.
Insights
- For medically screened people with NASH, vigorous intervals can be feasible when supervised and progressed gradually.
- Exercise capacity and insulin sensitivity may improve even if VO2peak does not.
- Modality flexibility is important for users with obesity and musculoskeletal limitations.
Limitations
- Very small sample.
- COVID-19 restrictions affected recruitment.
- Some outcomes could not be collected in all participants.
- HIIT group had higher medication burden at baseline.
- Real-world maintenance after supervised training was not tested.
Safety
- No HIIT-related adverse events or serious adverse events.
- Blood pressure was monitored during intervals and recovery to remain within safe limits.
- Multiple modalities were available for musculoskeletal limitations.