Effect of High‐Intensity Interval Training on Visceral and Liver Fat in Cardiac Rehabilitation: A Randomized Controlled Trial

Objective

This study aimed to investigate the effect of exercise intensity on visceral adipose tissue (VAT) and liver fat reduction in patients with coronary artery disease (CAD) over 3 months and the maintenance of improvements over 12 months.

Methods

Forty‐two participants with CAD were randomized to three sessions/week of either 4 × 4‐minute high‐intensity interval training (HIIT) or 40 minutes of usual care moderate‐intensity continuous training (MICT) for a 4‐week supervised cardiac rehabilitation program, followed by three home‐based sessions/week for 11 months. Liver fat (as intrahepatic lipid) and VAT were measured via magnetic resonance techniques. Data are mean change (95% CI).

Results

HIIT and MICT significantly reduced VAT over 3 months (−350 [−548 to −153] cm3 vs. −456 [−634 to −278] cm3; time × group effect: P  = 0.421), with further improvement over 12 months (−545 [−818 to −271] cm3 vs. −521 [−784 to −258] cm3; time × group effect: P  = 0.577) and no differences between groups. Both groups improved liver fat over 3 months, with HIIT tending to show greater reduction than MICT (−2.8% [−4.0% to −1.6%] vs. −1.4% [−2.4% to −0.4%]; time × group effect: P  = 0.077). After 12 months, improvements were maintained to a similar degree. Higher exercise intensity predicted liver fat reduction (β = −0.3 [−0.7 to 0.0]; P  = 0.042).

Conclusions

HIIT and MICT reduced VAT over 3 and 12 months. For liver fat, HIIT tended to provide a slightly greater reduction compared with MICT. These findings support HIIT as a beneficial adjunct or alternative to MICT for reducing visceral and liver fat in patients with CAD.