Statins blunt cardiorespiratory fitness improvements after exercise training and may affect fat oxidation adaptations to training.

To determine if long-term statin use in dyslipidemic individuals restricts the improvements in fat oxidation typically observed after an intense exercise-training program.

A total of 106 metabolic syndrome individuals either chronically medicated with statins (ie, statin group; n = 46) or statin naive (ie, control group; n = 60) completed a 16-week supervised high-intensity interval training program. Maximal rates of oxygen consumption (O_2MAX), fat oxidation (FO_MAX), and the shape of the workload-fat oxidation curve were assessed before and 48 hours after training in an overnight fasted state.

Starting from a similar value at baseline, both groups increased O_2MAX after training, but the increase was larger in the control than in the statin group (19.4% vs 12.6%; P = .013). Before training, FO_MAX in the statin group was lower (0.19 ± 0.08 vs 0.23 ± 0.07 g·min⁻¹; P = .023) and took place at a lower workload (33 ± 21 vs 37 ± 19 W; P = .015) than in the control group. After training, FO_MAX improved similarly in both groups (0.06 ± 0.08; 95% CI, 0.03-0.08 g·min⁻¹ and 0.05 ± 0.09; 95% CI, 0.03-0.07 g·min⁻¹, for statin and control groups, respectively; (P < .001). Still, after training, FO_MAX occurred at a 28% lower workload in the statin group (38 ± 26 vs 53 ± 32 W; P = .048). The O₂-workload slope decreased after training in both groups (both P < .001) along with reductions in the respiratory exchange ratio-workload slope. Fat oxidation increased at all workloads after training regardless of the use of statins.

Long-term statin treatment is associated with blunted exercise fat oxidation before exercise training. However, statin use does not attenuate the improvements in exercise fat oxidation (FO_MAX) derived from intense aerobic exercise training. This finding should encourage statin users to exercise-train to benefit from increased fat oxidation once their fitness level improves.